Heat pump sizing and brands?

Questions on how we spend our money and our time - consumer goods and services, home and vehicle, leisure and recreational activities
Topic Author
NYCaviator
Posts: 2334
Joined: Sat Apr 09, 2016 5:06 pm
Location: NYC

Heat pump sizing and brands?

Post by NYCaviator »

We’re getting quoted for a cold weather ducted heat pump. I’m really confused about sizing and want to get some opinions before I have the contractors out so I am somewhat informed.

Size
The space we need to heat and cool is around 2,800 sqft. For traditional AC, the online estimators said 5 ton unit. I looked at Mitsubishis ducted options, but it only goes up to 42,000 BTU and says “up to 2k sqft”. Many US homes are over 2k sqft these days, so are people using two heat pumps or are the Mitsubishi units only for smaller homes?

I plan to have the contractors run a manual J (if they will) but I’d like to go in with some idea of what to expect so I know if they’re full of it. I don’t want an oversized or undersized unit.

Brands
Aside from Mitsubishi, there are a ton of heat pump brands I’ve never heard of. Trane/Carrier/Lennox have heat pumps but they are harder to find info on. I’m skeptical about using cheap brands like Goodman, Rheem, “Mr. Cool,” or the myriad brands no one has heard of. How do you know what’s good and what’s not?

Warranty
I was really impressed with the Bosch literature. We have Bosch appliances and have been very happy with durability so I trust the company. Their heat pumps have a 10 year warranty, which looks like it’s the longest in the business. Are their units any good? Any other units that have good warranties?

Getting a heat pump is filled with potential pitfalls and misinformation. Contractors make it even more difficult to figure out what’s true/what’s correct because most of them seem to want to push you into a traditional unit.
WoostaGal
Posts: 279
Joined: Sat Feb 26, 2022 8:01 am

Re: Heat pump sizing and brands?

Post by WoostaGal »

After researching and getting estimates for about 8 months, I just signed a contract with Rycor, a NY company who reports they install more Mitsubishi units on the East coast than anyone else. My advice is to take your time and contact lots of contractors.

Estimates for my small house (1,000 ft2) varied widely from $18,000 to $40,000. The terms of each contract all varied widely. All the installers I contacted did a manual J to determine the capacity needed.

Mitsubishi 'Diamond Certified' installers (which Rycor is) can provide a 12 year warranty on parts and compressor. By signing a contract for installation during their off-season, Rycor offered a significant discount on my installation.

At my request, the sales person provided the Mitsubishi documentation that details the heating capacity of the product at various temperatures, the SEER, EER, HSPF, etc. It is a ENERGY STAR V6.1 Cold Climate model. You can look up different brands and models and compare their performance on the ASHP website:
https://ashp.neep.org/#!/

Factors that were important to me (not in any particular order):
1. Each indoor unit needs to be connected to an outdoor unit which does the work of heating/cooling. Some brands/configurations connect all of the indoor units to one outdoor unit. The Mitsubishi model I am getting has one outdoor unit for each indoor unit. If one of the outdoor units fails, I still have some heat/cooling from the others. If there is only one outdoor unit, then if it fails you lose all of your heating/cooling capacity.
2. The installation company I selected has been in business for a significant amount of time, has a large volume of heat pump business, and is a BBB member.
3. The installation company I selected handles getting permits. Another contractor did all of the installation and electrical work without getting a permit.
4. The installation company I selected takes care of all of the paperwork to get a significant rebate on the installation from my state. I pay only the balance after the state rebate has been applied. Some companies do not do the paperwork and/or front the money for the installation pending reimbursement from the state.
5. Reputation of the Mitsubishi heat pump product quality.
6. This installation company has a local branch in my city that can handle routine maintenance or repair.

Hope this helps a little and good luck! :happy
User avatar
SB1234
Posts: 1235
Joined: Sat Mar 10, 2018 6:41 pm
Location: Laniakea

Re: Heat pump sizing and brands?

Post by SB1234 »

In a heat pump you want to get one with the newer 'inverter technology". Those have a higher SEER.
You also want to avoid supplemental heating ( these are just electric heat coils and they will increase your electricity consumption). But depending on your weather avoiding supplemental heating may not be possible.

5T for 2800 sq ft sounds about right. But having multiple heat pumps is also popular in larger homes. So you could go with two systems. But I think that will be costlier.

Carrier and Bryant are same company and they both have highly rated heat pumps. Bryant have somewhat older technology and Carrier is considered flagship. I recently had a Bryant heat pump installed. I also had gotten quotes for Bosch, Lennox.

My suggestion is get at least 5 quotes. Each company will give you more info on what they can/cannot do. Each company will be specializing in one or two brands.
superstition: belief that market will one day come around to your concept of fair value
ScubaHogg
Posts: 3946
Joined: Sun Nov 06, 2011 2:02 pm

Re: Heat pump sizing and brands?

Post by ScubaHogg »

We did a remodel last winter. Our hvac guy, who we really like and has been in the business for 40 years, really loves the Bosch heat pumps. We had two installed for a two story, 4000’ sq ft home. A 5 ton and a 4 ton.

So far they have been great and have had zero problem keeping the house comfortable. I did install a natural gas furnace back up that kicks in at 20f, but that’s cause I’m paranoid. I am quite certain I didn’t need to do that.

We live in the usda zone 7 btw.
“Anyone may arrange his affairs so that his taxes shall be as low as possible; he is not bound to choose that pattern which best pays the treasury.” | ― Judge Learned Hand
rockstar
Posts: 6999
Joined: Mon Feb 03, 2020 5:51 pm

Re: Heat pump sizing and brands?

Post by rockstar »

ScubaHogg wrote: Mon Jun 03, 2024 11:26 am We did a remodel last winter. Our hvac guy, who we really like and has been in the business for 40 years, really loves the Bosch heat pumps. We had two installed for a two story, 4000’ sq ft home. A 5 ton and a 4 ton.

So far they have been great and have had zero problem keeping the house comfortable. I did install a natural gas furnace back up that kicks in at 20f, but that’s cause I’m paranoid. I am quite certain I didn’t need to do that.

We live in the usda zone 7 btw.
Interesting.

I talked to my buddy who has worked in HVAC for 20 years. He says he hates three things right now. First, heat pumps. Second, Carrier’s different blends of Freon. Third, smart thermostats. These all give him the most pain.

He basically told to me to stick with my gas furnace as long as I could, stick with the lowest SEER AC unit I could find, and he recommended only one smart thermostat worth getting. But the brand escapes me right now.
z0r
Posts: 272
Joined: Sat Nov 10, 2012 12:50 am

Re: Heat pump sizing and brands?

Post by z0r »

it's not too much trouble to do your own load calc ("manual j") - here's a free one. if you know your house well it might take a couple hours https://betterbuiltnw.com/hvac-sizing-tool

a house your size can benefit from two smaller systems, upstairs vs. downstairs, unless it's a giant ranch or something. it would depend on your existing ductwork though

if you have natural gas available then do some math on electricity vs. gas cost. there are only a few parts of the country with cheap enough electricity to make heat pumps competitive at low temps (I live in one!) - yes, even cold climate heat pumps, the type that I have, which might have cop of 2-3 in the temps where a large fraction of your annual heating load takes place. most places, natural gas is cheaper below some cutoff temp like 40 F or so. up to you if the complexity of dual fuel makes sense vs. the savings
Last edited by z0r on Mon Jun 03, 2024 11:40 am, edited 1 time in total.
mgensler
Posts: 383
Joined: Sun Aug 20, 2017 9:17 pm

Re: Heat pump sizing and brands?

Post by mgensler »

Op,

You are better off asking over at Green Building Advisor. It really depends on your climate, insulation, and air tightness of your home. If you are replacing a gas furnace or boiler you can do a fuel based calculation that will accurately size the equipment. Our house is 4,500 sq feet, above average amount of glass, and below to average insulation and air tightness. We're in climate zone 4a. We installed 4 Fujitsu mini splits for a total of 4 tons. It's been the perfect amount of heating/cooling even in extreme weather.
Pdxnative
Posts: 1039
Joined: Sat Nov 07, 2015 1:17 pm

Re: Heat pump sizing and brands?

Post by Pdxnative »

Mitsubishi, Bosch, Daikin are all good heat pump brands. Daikin tends to be the more moderately priced, generally the sweet spot in terms of value (not always).

The traditional US brands are generally playing catch up with heat pump technology but there are good options there too.

I’d find several good installers that specialize in the brands I listed and see what they say. A lot depends on your home and existing ductwork.

It’s true that some hvac contractors will steer people away from heat pumps. There are a lot of dinosaurs in the industry. If you can’t find good options from friends, sometimes local nonprofits focused on electrification can be a resource, or get a home energy audit and use that company as a resource. You can also check online reviews to see what these places are installing. Anyone not doing a large chunk of heat pump installs is worth avoiding.
User avatar
TomatoTomahto
Posts: 17579
Joined: Mon Apr 11, 2011 1:48 pm

Re: Heat pump sizing and brands?

Post by TomatoTomahto »

Our ASHP (air source heat pump) is from Fujitsu. It heats and cools our detached garage fine, even in the middle of Boston winters. Our GSHP (ground …) are by Water Furnace, and keep up with our 6.000 SF home. I think with incentives, GSHP are not the money pit some people would say.
I get the FI part but not the RE part of FIRE.
BirderInTraining
Posts: 15
Joined: Mon Jun 19, 2023 10:47 am

Re: Heat pump sizing and brands?

Post by BirderInTraining »

I live in zone 8. My house is about 2850 sq ft and has 3 ac/heat pump units (because of the unusual layout of the house). The house is 41 years old. The original units were Carrier. The first one to go was the one for the upstairs bedrooms. It quit after 27 years of excellent service with regular maintenance. The second one was replaced last August, after 40 years of service. I chose to replace it because it had a leak and the refrigerant it needed is now very expensive and I wanted a more efficient unit. The third unit is still going strong after 41 years. This is by way of saying that Carrier knows a thing or two about heat pumps. Though, the various contractors who came out to bid on the new unit last year all said "they don't make 'em like they used to anymore." But they were not selling Carrier.

Because of size limitations of the "closet" that houses the air handler, the only unit that would fit was Mitsubishi. In the end, the contractor installed a unit from a new-ish venture between Trane and Mitsubishi Electric. (Moral of the story: google the model numbers they will provide on the bid to make sure you are getting what you think are getting.) Amazingly I went with the lowest bidder (they were highly recommended by a friend) who was offering to install what turned out to be the best equipment of all the bids. (Google the model numbers of all the bids you get and you will see what they retail for. It will give you a good idea of quality (it often correlates highly with price, but you know that already) and how much the installer is hoping to make in labor/profit.) Before you accept a bid look up the SEER numbers. If you get a unit with (if I remember correctly) a SEER of 18 or higher, and you owe federal taxes at the end of the year, you will get a $2,000 tax credit. I also had the unit inspected by my city and qualified for an $800 rebate. I did all the legwork for the rebate and tax credit; it was easy to do. The new unit is a 1.5 ton and I paid $9,015, before the rebate and tax credit. I am over the moon with the new unit. It is so quiet and works really well. We had a polar vortex in January and the unit performed flawlessly. I had bids of over $17K for far worse equipment, so be sure to talk to friends and get several bids.

The Japanese know a thing or two about heat pumps. The unit I got has "hyper heat" (not sure about the name of the feature). Basically, when it gets really cold outside it does not fire up electrical coils and blows air over them (super expensive supplemental heat). I don't understand the technology but the installer showed me the top of the air handler and pointed out that there are no coils because it does not need them.

Last, as others have mentioned before, do not install a larger unit than what is there already. It will cool the rooms too quickly and won't pull out enough humidity and you will always be uncomfortable. Good luck.
z0r
Posts: 272
Joined: Sat Nov 10, 2012 12:50 am

Re: Heat pump sizing and brands?

Post by z0r »

BirderInTraining wrote: Mon Jun 03, 2024 12:47 pmIf you get a unit with (if I remember correctly) a SEER of 18 or higher, and you owe federal taxes at the end of the year, you will get a $2,000 tax credit
yeah... I just went through the fed tax credit stuff, it's pretty annoying to figure out

the ratings just changed from seer/hspf to seer2/hspf2. there's also cop and capacity maintenance requirements (or were? it keeps changing). and the country is divided into "north" and "south" giving you different reqs

https://www.energystar.gov/about/federa ... heat-pumps

for a purchasing decision, check the hspf2/seer2 numbers first, but the really important thing is then checking the list of qualifying equipment after figuring out if you're north or south, the "yes/no" columns for north/south credit in the sheet, which I think is the best way to defend yourself in an audit. get the csv/excel spreadsheet here:

https://www.energystar.gov/productfinde ... ps/results
bombcar
Posts: 1793
Joined: Sun Aug 12, 2007 6:41 pm

Re: Heat pump sizing and brands?

Post by bombcar »

Sq ft is a rule of thumb and is not entirely relevant. You may want to hire someone to do an energy audit if you're interested in using a heat pump, because the amount of heat and cooling you need is directly affected by airflow, envelope leaks, etc.

A brand new 4800 sq ft house well-built with all the modern energy saving devices may need much less HVAC than a drafty 100 year old 1000 sq ft.

If you want to go heat pump go with someone who specializes in them and knows what they're doing. If the only people around just do gas furnaces, stay on gas or import someone from a nearby city. A badly-sized heat pump improperly installed will be hell, whereas a mis-sized gas furnace will just run a bit longer at times.
WhyNotUs
Posts: 2690
Joined: Sun Apr 14, 2013 11:38 am

Re: Heat pump sizing and brands?

Post by WhyNotUs »

NYCaviator wrote: Mon Jun 03, 2024 9:01 am Size
The space we need to heat and cool is around 2,800 sqft. For traditional AC, the online estimators said 5 ton unit. I looked at Mitsubishis ducted options, but it only goes up to 42,000 BTU and says “up to 2k sqft”. Many US homes are over 2k sqft these days, so are people using two heat pumps or are the Mitsubishi units only for smaller homes?

I plan to have the contractors run a manual J (if they will) but I’d like to go in with some idea of what to expect so I know if they’re full of it. I don’t want an oversized or undersized unit.

As was noted, the specifics of your home are why online calculators are good for ballpark but not final calcs. Mistu website shows hyper heat units up to 54k BTU

Brands
Aside from Mitsubishi, there are a ton of heat pump brands I’ve never heard of. Trane/Carrier/Lennox have heat pumps but they are harder to find info on. I’m skeptical about using cheap brands like Goodman, Rheem, “Mr. Cool,” or the myriad brands no one has heard of. How do you know what’s good and what’s not?

Nothing wrong with Mitsu, in cold climates I see them as in the lead. I bought one from your cheap brand list and installed it myself for cost issues.

Warranty
I was really impressed with the Bosch literature. We have Bosch appliances and have been very happy with durability so I trust the company. Their heat pumps have a 10 year warranty, which looks like it’s the longest in the business. Are their units any good? Any other units that have good warranties?

If you have a local HVAC person that deals with Bosch, they should be fine. You can ask them but I think they use the same compressor as the Mitsu.

Getting a heat pump is filled with potential pitfalls and misinformation. Contractors make it even more difficult to figure out what’s true/what’s correct because most of them seem to want to push you into a traditional unit.

I think a big part of that is lack of familiarity and that green products have been oversold in the past. OTOH, this is very old and established technology and there is no black box involved. It has just not been popular in the US until recently.
I own the next hot stock- VTSAX
User avatar
hand
Posts: 2256
Joined: Sun May 17, 2009 8:42 pm

Re: Heat pump sizing and brands?

Post by hand »

Midea is the manufacturer behind many of the mid-tier brands and does a fine job.
Mitsubishi is generally considered top tier in terms of build quality.

One thing my research pointed to is susceptibility of many heat pumps to electrical surges / brown outs (Mitsubishi apparently builds in some level of protection, but most don't). For that reason supplemental surge/low voltage protection at a cost of perhaps $300 is recommended for most installs.

Given the importance of the installer in the final system, I ended up with a Samsung (Midea) unit instead of my preferred hardware from Mitsubishi and have been happy with the operations (and the slightly reduced cost) through both hot and cold seasons.
Topic Author
NYCaviator
Posts: 2334
Joined: Sat Apr 09, 2016 5:06 pm
Location: NYC

Re: Heat pump sizing and brands?

Post by NYCaviator »

z0r wrote: Mon Jun 03, 2024 11:37 am if you have natural gas available then do some math on electricity vs. gas cost. there are only a few parts of the country with cheap enough electricity to make heat pumps competitive at low temps (I live in one!) - yes, even cold climate heat pumps, the type that I have, which might have cop of 2-3 in the temps where a large fraction of your annual heating load takes place. most places, natural gas is cheaper below some cutoff temp like 40 F or so. up to you if the complexity of dual fuel makes sense vs. the savings
What's the best way to do this? I'd prefer to get a heat pump, but I don't necessarily want to pay more for it. Our electric rates in summer ranges from .12 to .32 per KWH depending on the time of day. In the winter its .12 to .20

In our coldest month this past winter, we used 108 therms with our current ultra high efficiency gas furnace, tankless water heater, and gas range and and paid $111 in gas. It's hard to see what you're "truly" spending on gas because of all the random fees and charges that they tack on.

Our electric prices seem to fluctuate a lot as well. It's hard to decide if a heat pump will be worth it since I think we have pretty cheap gas. Even during our worst months, our combined electric and gas bill has never been higher than $175.
bombcar
Posts: 1793
Joined: Sun Aug 12, 2007 6:41 pm

Re: Heat pump sizing and brands?

Post by bombcar »

NYCaviator wrote: Mon Jun 03, 2024 2:47 pm Our electric prices seem to fluctuate a lot as well. It's hard to decide if a heat pump will be worth it since I think we have pretty cheap gas.
The absolute "best" way is to have the option of running either/both so you can directly compare.

The second best is to find a house as similar to yours that has a heat pump, and look at actual numbers.

The third best is to (assuming you have other things on gas and can't completely cancel service) do a summer/winter comparison between bills and get a "total heat spend" per year; the heat pump cannot save you more than that. If that number is too low to do it, just stop there.

If it's high enough that it seems it might be worthwhile, then continue investigating.
Topic Author
NYCaviator
Posts: 2334
Joined: Sat Apr 09, 2016 5:06 pm
Location: NYC

Re: Heat pump sizing and brands?

Post by NYCaviator »

bombcar wrote: Mon Jun 03, 2024 2:50 pm
NYCaviator wrote: Mon Jun 03, 2024 2:47 pm Our electric prices seem to fluctuate a lot as well. It's hard to decide if a heat pump will be worth it since I think we have pretty cheap gas.
The absolute "best" way is to have the option of running either/both so you can directly compare.

The second best is to find a house as similar to yours that has a heat pump, and look at actual numbers.

The third best is to (assuming you have other things on gas and can't completely cancel service) do a summer/winter comparison between bills and get a "total heat spend" per year; the heat pump cannot save you more than that. If that number is too low to do it, just stop there.

If it's high enough that it seems it might be worthwhile, then continue investigating.
That's a good point. No one in my area has a heat pump that I know about. The houses are newer so most are just at the point of needing new HVAC systems.

Interestingly, our summer bills are very similar to our winter bills, except that we pay more for electricity than gas in the summer and more for gas than electricity in the winter. Our furnace is UHE, but our A/C is builder grade crap that I'm almost certain is too small for the house, so I'm sure getting a larger capacity and higher SEER A/C unit would cut down on the electric bill substantially.
bombcar
Posts: 1793
Joined: Sun Aug 12, 2007 6:41 pm

Re: Heat pump sizing and brands?

Post by bombcar »

NYCaviator wrote: Mon Jun 03, 2024 2:56 pm Interestingly, our summer bills are very similar to our winter bills, except that we pay more for electricity than gas in the summer and more for gas than electricity in the winter. Our furnace is UHE, but our A/C is builder grade crap that I'm almost certain is too small for the house, so I'm sure getting a larger capacity and higher SEER A/C unit would cut down on the electric bill substantially.
Capacity for A/C is weird - you basically want it to run most of the time but not all of the time 95% of the time or something like that. If it only runs for short periods of time, it's oversized and will freeze up, if it runs flat out all the time (not just the hottest days) it will burn out.

Improving SEER would help. Basically, if the system works and keeps the house comfortable, it's sized right, and I would not just assume "bigger is better".
talzara
Posts: 4931
Joined: Thu Feb 12, 2009 6:40 pm

Re: Heat pump sizing and brands?

Post by talzara »

NYCaviator wrote: Mon Jun 03, 2024 9:01 am I was really impressed with the Bosch literature. We have Bosch appliances and have been very happy with durability so I trust the company. Their heat pumps have a 10 year warranty, which looks like it’s the longest in the business. Are their units any good?
WhyNotUs wrote: Mon Jun 03, 2024 1:39 pm If you have a local HVAC person that deals with Bosch, they should be fine. You can ask them but I think they use the same compressor as the Mitsu.
hand wrote: Mon Jun 03, 2024 2:44 pm Midea is the manufacturer behind many of the mid-tier brands and does a fine job. ... Given the importance of the installer in the final system, I ended up with a Samsung (Midea) unit instead of my preferred hardware from Mitsubishi and have been happy with the operations (and the slightly reduced cost) through both hot and cold seasons.
The Bosch IDS is manufactured by Midea. Bosch is popular in the Northeast, especially in the New York City area. The IDS has a good reputation for reliability.

Mitsubishi does not sell to rebadgers. Mitsubishi Trane mini-splits are branded with both companies' names.
talzara
Posts: 4931
Joined: Thu Feb 12, 2009 6:40 pm

Re: Heat pump sizing and brands?

Post by talzara »

bombcar wrote: Mon Jun 03, 2024 3:18 pm Capacity for A/C is weird - you basically want it to run most of the time but not all of the time 95% of the time or something like that. If it only runs for short periods of time, it's oversized and will freeze up, if it runs flat out all the time (not just the hottest days) it will burn out.
The OP is considering inverter units that can reduce capacity to match the load. The Bosch IDS (Inverter Ducted Split) even has "inverter" in the product name.

Cold-climate heat pumps use inverters because they are used in heating-dominated climates. Sizing the unit for heating will make it oversized for cooling. They have to be able to reduce their capacity in summer to match the load.
talzara
Posts: 4931
Joined: Thu Feb 12, 2009 6:40 pm

Re: Heat pump sizing and brands?

Post by talzara »

BirderInTraining wrote: Mon Jun 03, 2024 12:47 pm The Japanese know a thing or two about heat pumps. The unit I got has "hyper heat" (not sure about the name of the feature). Basically, when it gets really cold outside it does not fire up electrical coils and blows air over them (super expensive supplemental heat). I don't understand the technology but the installer showed me the top of the air handler and pointed out that there are no coils because it does not need them.
Hyper Heat is Mitsubishi's branding for vapor injection.

All of the major Asian HVAC manufacturers have at least one product that has vapor injection.

The American HVAC manufacturers are 10-20 years behind the Japanese. Trane is planning to release its first residential heat pump with vapor injection next year! (Mitsubishi Trane mini-splits are designed by Mitsubishi.)
z0r
Posts: 272
Joined: Sat Nov 10, 2012 12:50 am

Re: Heat pump sizing and brands?

Post by z0r »

NYCaviator wrote: Mon Jun 03, 2024 2:47 pm
z0r wrote: Mon Jun 03, 2024 11:37 am if you have natural gas available then do some math on electricity vs. gas cost. there are only a few parts of the country with cheap enough electricity to make heat pumps competitive at low temps (I live in one!) - yes, even cold climate heat pumps, the type that I have, which might have cop of 2-3 in the temps where a large fraction of your annual heating load takes place. most places, natural gas is cheaper below some cutoff temp like 40 F or so. up to you if the complexity of dual fuel makes sense vs. the savings
What's the best way to do this? I'd prefer to get a heat pump, but I don't necessarily want to pay more for it. Our electric rates in summer ranges from .12 to .32 per KWH depending on the time of day. In the winter its .12 to .20

In our coldest month this past winter, we used 108 therms with our current ultra high efficiency gas furnace, tankless water heater, and gas range and and paid $111 in gas. It's hard to see what you're "truly" spending on gas because of all the random fees and charges that they tack on.

Our electric prices seem to fluctuate a lot as well. It's hard to decide if a heat pump will be worth it since I think we have pretty cheap gas. Even during our worst months, our combined electric and gas bill has never been higher than $175.
I'm not aware of a quick calculator but here's the math

I'll use my own rates as an example - 10.3 cents/kWh and $1.30/therm (but therm price varies a lot)

https://www.nwnatural.com/about-us/rate ... ling-rates

https://www.eweb.org/my-account/budget- ... al-pricing

assuming a .95 efficient gas furnace, I get a therm of heat for $1.36/therm (1.30*.95)

heat pump output is rated by "coefficient of performance" heat out vs. heat in ratio, cop, which varies with outside temp

with a heat pump, I can get a therm of heat for ([1/cop] * .103 $/kWh * 29.3 kWh/therm) = $3.02 / cop

this means I need a cop of 3.02 / 1.36 = 2.2x to break even. above that cop my heat pump saves money, below it loses it

cop ranges from ~2 to ~4 for a cold climate ducted heat pump, so I'm in range... it's lower at low outside temps and higher at high temps. from here I can look up a heat pump of interest and find the break even temp. for my low end cold climate heat pump (gree flexx) this is around 15-25F depending on size https://www.greecomfort.com/assets/our- ... -ao-bh.pdf

you can then look at the NEEP sizing tool for your zip code and plug the heat pump in to see a chart of % of hours of heating needed that are above and below this crossover temp:

https://ashp.neep.org/#!/

some years we never go below 25F here so it's a clean win for me, at current pricing. when I ran numbers last year gas was cheaper and it was more like 45F. I do think there's value in gas backup, hard to quantify, but not nothing
chet96
Posts: 244
Joined: Fri Feb 21, 2020 8:14 am

Re: Heat pump sizing and brands?

Post by chet96 »

My experience only here. I had a Mitsubishi mini-split system installed in my office a few years back.

It's an overhead cartridge, and it was dead quiet for about 3 years. However, the fan runs constantly. According to the installer, this is normal. It now clicks fairly loudly when it calls for heat. If this was in a bedroom, I would be pretty upset.

According to google anyway, it seems to be a common problem with the Mitsubishi head units. It may be worth asking about if you are installing in bedrooms.
talzara
Posts: 4931
Joined: Thu Feb 12, 2009 6:40 pm

Re: Heat pump sizing and brands?

Post by talzara »

chet96 wrote: Mon Jun 03, 2024 4:00 pm My experience only here. I had a Mitsubishi mini-split system installed in my office a few years back.

It's an overhead cartridge, and it was dead quiet for about 3 years. However, the fan runs constantly. According to the installer, this is normal. It now clicks fairly loudly when it calls for heat. If this was in a bedroom, I would be pretty upset.

According to google anyway, it seems to be a common problem with the Mitsubishi head units. It may be worth asking about if you are installing in bedrooms.
The OP is looking at ducted heat pumps, not ductless.
alfaspider
Posts: 4999
Joined: Wed Sep 09, 2015 4:44 pm

Re: Heat pump sizing and brands?

Post by alfaspider »

talzara wrote: Mon Jun 03, 2024 3:29 pm
bombcar wrote: Mon Jun 03, 2024 3:18 pm Capacity for A/C is weird - you basically want it to run most of the time but not all of the time 95% of the time or something like that. If it only runs for short periods of time, it's oversized and will freeze up, if it runs flat out all the time (not just the hottest days) it will burn out.
The OP is considering inverter units that can reduce capacity to match the load. The Bosch IDS (Inverter Ducted Split) even has "inverter" in the product name.

Cold-climate heat pumps use inverters because they are used in heating-dominated climates. Sizing the unit for heating will make it oversized for cooling. They have to be able to reduce their capacity in summer to match the load.
Yes. An oversized unit for cooling isn't a big issue with an inverter unit (which is a variable speed compressor). In a traditional single stage a/c, you end up with short cycling and damp air (not enough humidity removal) if the a/c is oversized. Since a variable unit can run below its max capacity, it doesn't have as much of an issue with being oversized. That preserves capacity for when you want max heat (and don't want to have to resort to backup coils).

I have a Carrier Infinity heat pump with no backup coil. It doesn't get super cold here, but it was able keep set temps of 75 no problem when it dropped into the high teens in a relatively poorly insulated house.
chet96
Posts: 244
Joined: Fri Feb 21, 2020 8:14 am

Re: Heat pump sizing and brands?

Post by chet96 »

talzara wrote: Mon Jun 03, 2024 4:14 pm
chet96 wrote: Mon Jun 03, 2024 4:00 pm My experience only here. I had a Mitsubishi mini-split system installed in my office a few years back.

It's an overhead cartridge, and it was dead quiet for about 3 years. However, the fan runs constantly. According to the installer, this is normal. It now clicks fairly loudly when it calls for heat. If this was in a bedroom, I would be pretty upset.

According to google anyway, it seems to be a common problem with the Mitsubishi head units. It may be worth asking about if you are installing in bedrooms.
The OP is looking at ducted heat pumps, not ductless.
Sorry...I read ductless. Disregard.
chet96
Posts: 244
Joined: Fri Feb 21, 2020 8:14 am

Re: Heat pump sizing and brands?

Post by chet96 »

Deleted...posted in error.
User avatar
id0ntkn0wjack
Posts: 251
Joined: Wed Nov 30, 2022 3:12 pm

Re: Heat pump sizing and brands?

Post by id0ntkn0wjack »

NYCaviator wrote: Mon Jun 03, 2024 9:01 am

Size
The space we need to heat and cool is around 2,800 sqft. For traditional AC, the online estimators said 5 ton unit. I looked at Mitsubishis ducted options, but it only goes up to 42,000 BTU and says “up to 2k sqft”. Many US homes are over 2k sqft these days, so are people using two heat pumps or are the Mitsubishi units only for smaller homes?

You are far better off to get two smaller units than a single 5-ton:

https://www.energyvanguard.com/blog/5-t ... ht-answer/
I moved 10% of my equities into BLV (Vanguard Long Term Bond ETF) in January 2021. Follow my advice at your own peril.
andypanda
Posts: 2102
Joined: Sun Nov 12, 2017 8:11 pm
Location: Richmond, Virginia

Re: Heat pump sizing and brands?

Post by andypanda »

"Sq ft is a rule of thumb and is not entirely relevant."

I would say it is not relevant at all. You do not heat or cool square feet, you heat and cool cubic feet. It's the volume that matters.
Are your ceilings 8', 9', or 10'? Or maybe you have some 12' or 14' in a room or two.
That's why the calculations are important, along with sun exposure in your location, insulation, quality of windows, and all that other stuff.

But it's easier to divide 400 or 600 into 2400 sq.ft. and round it off to the nearest ton.
One other thing I learned over the years browsing HVAC-TALK - each floor gets its own system. Zoning one system for two or more stories is a difficult black art at best considering the way heat rises and cool air falls.
Topic Author
NYCaviator
Posts: 2334
Joined: Sat Apr 09, 2016 5:06 pm
Location: NYC

Re: Heat pump sizing and brands?

Post by NYCaviator »

id0ntkn0wjack wrote: Mon Jun 03, 2024 5:57 pm
NYCaviator wrote: Mon Jun 03, 2024 9:01 am

Size
The space we need to heat and cool is around 2,800 sqft. For traditional AC, the online estimators said 5 ton unit. I looked at Mitsubishis ducted options, but it only goes up to 42,000 BTU and says “up to 2k sqft”. Many US homes are over 2k sqft these days, so are people using two heat pumps or are the Mitsubishi units only for smaller homes?

You are far better off to get two smaller units than a single 5-ton:

https://www.energyvanguard.com/blog/5-t ... ht-answer/
I think that would require a lot of work on the ducts. The house was built with a single unit, so I assume I’d have to cut drywall and redo the ductwork?
Valuethinker
Posts: 49659
Joined: Fri May 11, 2007 11:07 am

Re: Heat pump sizing and brands?

Post by Valuethinker »

rockstar wrote: Mon Jun 03, 2024 11:29 am
ScubaHogg wrote: Mon Jun 03, 2024 11:26 am We did a remodel last winter. Our hvac guy, who we really like and has been in the business for 40 years, really loves the Bosch heat pumps. We had two installed for a two story, 4000’ sq ft home. A 5 ton and a 4 ton.

So far they have been great and have had zero problem keeping the house comfortable. I did install a natural gas furnace back up that kicks in at 20f, but that’s cause I’m paranoid. I am quite certain I didn’t need to do that.

We live in the usda zone 7 btw.
Interesting.

I talked to my buddy who has worked in HVAC for 20 years. He says he hates three things right now. First, heat pumps. Second, Carrier’s different blends of Freon. Third, smart thermostats. These all give him the most pain.

He basically told to me to stick with my gas furnace as long as I could, stick with the lowest SEER AC unit I could find, and he recommended only one smart thermostat worth getting. But the brand escapes me right now.
I don't disagree with the Keep It Simple S, principle. Gas furnaces are not the best for the environment, but gas is mostly pretty cheap in North America (New England I think has some quite high gas prices).

However I don't agree with lowest SEER AC:

- electricity is not cheap in many places (like New York/ New England) and increasingly is "tiered" by usage (California)

- summers are getting hotter. That's a consistent story I have from many friends and relations in the eastern half of North America. And I know people in Vancouver BC who happily lived without AC for decades. After the recent Heat Dome experiences, they are now installing it (also it can help filter out wildfire smoke). A more efficient AC won't have to work as hard in really hot temperatures and may keep you more comfortable.

(to give you an example. London England the average June-August temp is probably around 70 F. 2 summers ago, we managed over 100 for a couple of days. Tubes (subway trains) are not air conditioned generally. Office and cinema AC is not really up to the challenge. Very few homes would have air conditioning of any sort)).

- you are likely only going to do this once in the life of the home. So you want a degree of "future proofing" and that is what more energy efficient appliances do

So I would say SEER 15 at least. And SEER 18 possibly. Beyond that the incremental savings are probably not worth it.
bendix
Posts: 921
Joined: Thu Feb 16, 2023 9:35 pm

Re: Heat pump sizing and brands?

Post by bendix »

NYCaviator wrote: Mon Jun 03, 2024 9:01 am We’re getting quoted for a cold weather ducted heat pump. I’m really confused about sizing and want to get some opinions before I have the contractors out so I am somewhat informed.

Size
The space we need to heat and cool is around 2,800 sqft. For traditional AC, the online estimators said 5 ton unit. I looked at Mitsubishis ducted options, but it only goes up to 42,000 BTU and says “up to 2k sqft”. Many US homes are over 2k sqft these days, so are people using two heat pumps or are the Mitsubishi units only for smaller homes?

I plan to have the contractors run a manual J (if they will) but I’d like to go in with some idea of what to expect so I know if they’re full of it. I don’t want an oversized or undersized unit.

Brands
Aside from Mitsubishi, there are a ton of heat pump brands I’ve never heard of. Trane/Carrier/Lennox have heat pumps but they are harder to find info on. I’m skeptical about using cheap brands like Goodman, Rheem, “Mr. Cool,” or the myriad brands no one has heard of. How do you know what’s good and what’s not?

Warranty
I was really impressed with the Bosch literature. We have Bosch appliances and have been very happy with durability so I trust the company. Their heat pumps have a 10 year warranty, which looks like it’s the longest in the business. Are their units any good? Any other units that have good warranties?

Getting a heat pump is filled with potential pitfalls and misinformation. Contractors make it even more difficult to figure out what’s true/what’s correct because most of them seem to want to push you into a traditional unit.
I spent a fair amount of time researching this but have no first hand experience with it. From everything I could read, Mitsubishi is sort of the gold standard, followed by Fujitsu (which doesnt have certified installers everywhere it seems) and Daikin. Bosch heat pumps sold in the US are made in China and I am not even sure they´re actually engineered/built by Bosch or just whitelabeled. What I read is that these Bosch´s arent that great and also surprisingly cheap.
User avatar
firebirdparts
Posts: 4555
Joined: Thu Jun 13, 2019 4:21 pm
Location: Southern Appalachia

Re: Heat pump sizing and brands?

Post by firebirdparts »

5 ton is a common size, but I suppose it is the largest common size.

So if you have ductwork for a single system, just do the 5 ton.
This time is the same
JoeNJ28
Posts: 618
Joined: Sat Aug 25, 2018 9:13 am

Re: Heat pump sizing and brands?

Post by JoeNJ28 »

A right sized mini split is key to comfort and efficiency. Took awhile to find a contractor who wouldn't just use a sq foot = x ton metric. We have had a 18,000 btu mini split that is used to do an entire 2,000 sq ft of space and never has issues whether its -3 out out or 102. Insulation and air sealing make massive difference in your loads and are cost effective in perpetuity once you install them. Grab some cans of spray foam or sealing tape go seal some cracks, throw another layer of insulation in the attic and you will be amazed how it decreased your heating and cooling loads.
alfaspider
Posts: 4999
Joined: Wed Sep 09, 2015 4:44 pm

Re: Heat pump sizing and brands?

Post by alfaspider »

Valuethinker wrote: Tue Jun 04, 2024 3:25 am
rockstar wrote: Mon Jun 03, 2024 11:29 am
ScubaHogg wrote: Mon Jun 03, 2024 11:26 am We did a remodel last winter. Our hvac guy, who we really like and has been in the business for 40 years, really loves the Bosch heat pumps. We had two installed for a two story, 4000’ sq ft home. A 5 ton and a 4 ton.

So far they have been great and have had zero problem keeping the house comfortable. I did install a natural gas furnace back up that kicks in at 20f, but that’s cause I’m paranoid. I am quite certain I didn’t need to do that.

We live in the usda zone 7 btw.
Interesting.

I talked to my buddy who has worked in HVAC for 20 years. He says he hates three things right now. First, heat pumps. Second, Carrier’s different blends of Freon. Third, smart thermostats. These all give him the most pain.

He basically told to me to stick with my gas furnace as long as I could, stick with the lowest SEER AC unit I could find, and he recommended only one smart thermostat worth getting. But the brand escapes me right now.
I don't disagree with the Keep It Simple S, principle. Gas furnaces are not the best for the environment, but gas is mostly pretty cheap in North America (New England I think has some quite high gas prices).

However I don't agree with lowest SEER AC:

- electricity is not cheap in many places (like New York/ New England) and increasingly is "tiered" by usage (California)

- summers are getting hotter. That's a consistent story I have from many friends and relations in the eastern half of North America. And I know people in Vancouver BC who happily lived without AC for decades. After the recent Heat Dome experiences, they are now installing it (also it can help filter out wildfire smoke). A more efficient AC won't have to work as hard in really hot temperatures and may keep you more comfortable.

(to give you an example. London England the average June-August temp is probably around 70 F. 2 summers ago, we managed over 100 for a couple of days. Tubes (subway trains) are not air conditioned generally. Office and cinema AC is not really up to the challenge. Very few homes would have air conditioning of any sort)).

- you are likely only going to do this once in the life of the home. So you want a degree of "future proofing" and that is what more energy efficient appliances do

So I would say SEER 15 at least. And SEER 18 possibly. Beyond that the incremental savings are probably not worth it.
1) I'd say the things that annoy an HVAC guy may not be the things that annoy the homeowner. For example, my Carrier smart thermostat required 30 minutes for program and setup, vs a "dumb" thermostat that would have been plug and play. If you install HVAC for a living, an extra 30 minutes after you are otherwise done with the job is a huge annoyance. But that's irrelevant if you are the customer.

2) If you are going heat pump, efficient cooling is a byproduct of efficient heating.

3) The efficiency of a/c you want may depend on climate and electricity bills. The Gulf coast benefits a lot more from efficient a/c units than a place like upstate NY where they are used less frequently. There are calculators where you can run the numbers. Keep in mind that efficient heat pumps qualify for a tax credit that may narrow the difference.
z0r
Posts: 272
Joined: Sat Nov 10, 2012 12:50 am

Re: Heat pump sizing and brands?

Post by z0r »

Valuethinker wrote: Tue Jun 04, 2024 3:25 am I don't disagree with the Keep It Simple S, principle. Gas furnaces are not the best for the environment, but gas is mostly pretty cheap in North America (New England I think has some quite high gas prices).

However I don't agree with lowest SEER AC:

- electricity is not cheap in many places (like New York/ New England) and increasingly is "tiered" by usage (California)

- summers are getting hotter. That's a consistent story I have from many friends and relations in the eastern half of North America. And I know people in Vancouver BC who happily lived without AC for decades. After the recent Heat Dome experiences, they are now installing it (also it can help filter out wildfire smoke). A more efficient AC won't have to work as hard in really hot temperatures and may keep you more comfortable.

(to give you an example. London England the average June-August temp is probably around 70 F. 2 summers ago, we managed over 100 for a couple of days. Tubes (subway trains) are not air conditioned generally. Office and cinema AC is not really up to the challenge. Very few homes would have air conditioning of any sort)).

- you are likely only going to do this once in the life of the home. So you want a degree of "future proofing" and that is what more energy efficient appliances do

So I would say SEER 15 at least. And SEER 18 possibly. Beyond that the incremental savings are probably not worth it.
the low seer recommendation is likely to do with repairs and total cost of ownership. as you move beyond ~14 seer2/15 seer1 the machine typically has to add logic somewhere, increasing repair costs a lot. the 14 seer2 models are incredibly simple if you pull the panel and look inside - just a few relays, the start capacitor, almost nothing to them. they're so simple they can be repaired with generic (!) parts in many cases. machines with higher seer end up with little computers in them - more parts to fail, SOFTWARE, harder troubleshooting, no generic repairs

your point about balancing cost to own with energy cost is well taken

AC output ratings are normalized - all else being equal a 14 vs. 18 seer unit will have the same output, just a larger electricity input for the 14 seer

re: vancouver BC - in the pnw we're lucky in that summer humidity is NOT a concern and can be pretty much ignored for AC sizing purposes. oversizing AC is thus less of a problem than most parts of the country
rockstar
Posts: 6999
Joined: Mon Feb 03, 2020 5:51 pm

Re: Heat pump sizing and brands?

Post by rockstar »

Valuethinker wrote: Tue Jun 04, 2024 3:25 am
rockstar wrote: Mon Jun 03, 2024 11:29 am
ScubaHogg wrote: Mon Jun 03, 2024 11:26 am We did a remodel last winter. Our hvac guy, who we really like and has been in the business for 40 years, really loves the Bosch heat pumps. We had two installed for a two story, 4000’ sq ft home. A 5 ton and a 4 ton.

So far they have been great and have had zero problem keeping the house comfortable. I did install a natural gas furnace back up that kicks in at 20f, but that’s cause I’m paranoid. I am quite certain I didn’t need to do that.

We live in the usda zone 7 btw.
Interesting.

I talked to my buddy who has worked in HVAC for 20 years. He says he hates three things right now. First, heat pumps. Second, Carrier’s different blends of Freon. Third, smart thermostats. These all give him the most pain.

He basically told to me to stick with my gas furnace as long as I could, stick with the lowest SEER AC unit I could find, and he recommended only one smart thermostat worth getting. But the brand escapes me right now.
I don't disagree with the Keep It Simple S, principle. Gas furnaces are not the best for the environment, but gas is mostly pretty cheap in North America (New England I think has some quite high gas prices).

However I don't agree with lowest SEER AC:

- electricity is not cheap in many places (like New York/ New England) and increasingly is "tiered" by usage (California)

- summers are getting hotter. That's a consistent story I have from many friends and relations in the eastern half of North America. And I know people in Vancouver BC who happily lived without AC for decades. After the recent Heat Dome experiences, they are now installing it (also it can help filter out wildfire smoke). A more efficient AC won't have to work as hard in really hot temperatures and may keep you more comfortable.

(to give you an example. London England the average June-August temp is probably around 70 F. 2 summers ago, we managed over 100 for a couple of days. Tubes (subway trains) are not air conditioned generally. Office and cinema AC is not really up to the challenge. Very few homes would have air conditioning of any sort)).

- you are likely only going to do this once in the life of the home. So you want a degree of "future proofing" and that is what more energy efficient appliances do

So I would say SEER 15 at least. And SEER 18 possibly. Beyond that the incremental savings are probably not worth it.
The reason he gave me for going with the lowest SEER was to reduce maintenance costs. The higher the SEER, the more complex the unit, the more expensive the parts, and the harder it is to repair the unit. So he said I would end up paying more in the long run as the service plus parts would offset the energy savings.
Valuethinker
Posts: 49659
Joined: Fri May 11, 2007 11:07 am

Re: Heat pump sizing and brands?

Post by Valuethinker »

rockstar wrote: Tue Jun 04, 2024 10:08 am
The reason he gave me for going with the lowest SEER was to reduce maintenance costs. The higher the SEER, the more complex the unit, the more expensive the parts, and the harder it is to repair the unit. So he said I would end up paying more in the long run as the service plus parts would offset the energy savings.
Just lining up the 2 points (above & below, from different posters) it's probably reasonable to say that SEER 14/15 is a good compromise (I am out of date as to what the allowed minimum is in the USA now, in any case).

It is also fair to say that more complex electronics means more things to go wrong.

If you have high domestic electricity prices then it's something to consider carefully. Fortunately the parts of the USA with the biggest AC demands - the South - also tend to have low electricity prices.

A lot of discussion here does centre around 2-speed and variable-speed. The consensus seems to be this does a lot for comfort over the cheapest units. In most climates, humidity is what is causing the uncomfortable feelings. Without the variable speed, the system cycles on and off too much - from clammy cold to too hot and back again.
the low seer recommendation is likely to do with repairs and total cost of ownership. as you move beyond ~14 seer2/15 seer1 the machine typically has to add logic somewhere, increasing repair costs a lot. the 14 seer2 models are incredibly simple if you pull the panel and look inside - just a few relays, the start capacitor, almost nothing to them. they're so simple they can be repaired with generic (!) parts in many cases. machines with higher seer end up with little computers in them - more parts to fail, SOFTWARE, harder troubleshooting, no generic repairs

your point about balancing cost to own with energy cost is well taken

AC output ratings are normalized - all else being equal a 14 vs. 18 seer unit will have the same output, just a larger electricity input for the 14 seer

re: vancouver BC - in the pnw we're lucky in that summer humidity is NOT a concern and can be pretty much ignored for AC sizing purposes. oversizing AC is thus less of a problem than most parts of the country
My understanding is the "Heat Dome" was humid as well as hot? Vancouver is a wet city, any time of year, so I am pretty sure they do a fairly humid heat, when it gets hot (London England is the same).

Pacific Northwest has very low energy costs, I understand -- as low as some of the south-eastern states.
Valuethinker
Posts: 49659
Joined: Fri May 11, 2007 11:07 am

Re: Heat pump sizing and brands?

Post by Valuethinker »

bendix wrote: Tue Jun 04, 2024 5:44 am
NYCaviator wrote: Mon Jun 03, 2024 9:01 am We’re getting quoted for a cold weather ducted heat pump. I’m really confused about sizing and want to get some opinions before I have the contractors out so I am somewhat informed.

Size
The space we need to heat and cool is around 2,800 sqft. For traditional AC, the online estimators said 5 ton unit. I looked at Mitsubishis ducted options, but it only goes up to 42,000 BTU and says “up to 2k sqft”. Many US homes are over 2k sqft these days, so are people using two heat pumps or are the Mitsubishi units only for smaller homes?

I plan to have the contractors run a manual J (if they will) but I’d like to go in with some idea of what to expect so I know if they’re full of it. I don’t want an oversized or undersized unit.

Brands
Aside from Mitsubishi, there are a ton of heat pump brands I’ve never heard of. Trane/Carrier/Lennox have heat pumps but they are harder to find info on. I’m skeptical about using cheap brands like Goodman, Rheem, “Mr. Cool,” or the myriad brands no one has heard of. How do you know what’s good and what’s not?

Warranty
I was really impressed with the Bosch literature. We have Bosch appliances and have been very happy with durability so I trust the company. Their heat pumps have a 10 year warranty, which looks like it’s the longest in the business. Are their units any good? Any other units that have good warranties?

Getting a heat pump is filled with potential pitfalls and misinformation. Contractors make it even more difficult to figure out what’s true/what’s correct because most of them seem to want to push you into a traditional unit.
I spent a fair amount of time researching this but have no first hand experience with it. From everything I could read, Mitsubishi is sort of the gold standard, followed by Fujitsu (which doesnt have certified installers everywhere it seems) and Daikin. Bosch heat pumps sold in the US are made in China and I am not even sure they´re actually engineered/built by Bosch or just whitelabeled. What I read is that these Bosch´s arent that great and also surprisingly cheap.
My (maybe wrong) understanding is that at the low end, all of the major HP manufacturers are using Chinese-made product.

At the higher end, components may still come from China.

The big US brands are Trane/ Carrier/ Lennox. Goodman on the "value" end. Some of these brands are parts of the same companies.

From what talzara and other posters have said, US manufacturers come from an Air Conditioning heritage, where the heating functionality was added on, for mild climates (US South). Japanese manufacturers are much better on the heating side, because of Japan's extremes of temperature (both ways). In line with the general orientation of Japanese manufacturing, I would imagine the quality is good.
alfaspider
Posts: 4999
Joined: Wed Sep 09, 2015 4:44 pm

Re: Heat pump sizing and brands?

Post by alfaspider »

Valuethinker wrote: Tue Jun 04, 2024 11:41 am
rockstar wrote: Tue Jun 04, 2024 10:08 am
The reason he gave me for going with the lowest SEER was to reduce maintenance costs. The higher the SEER, the more complex the unit, the more expensive the parts, and the harder it is to repair the unit. So he said I would end up paying more in the long run as the service plus parts would offset the energy savings.
Just lining up the 2 points (above & below, from different posters) it's probably reasonable to say that SEER 14/15 is a good compromise (I am out of date as to what the allowed minimum is in the USA now, in any case).

It is also fair to say that more complex electronics means more things to go wrong.

If you have high domestic electricity prices then it's something to consider carefully. Fortunately the parts of the USA with the biggest AC demands - the South - also tend to have low electricity prices.

A lot of discussion here does centre around 2-speed and variable-speed. The consensus seems to be this does a lot for comfort over the cheapest units. In most climates, humidity is what is causing the uncomfortable feelings. Without the variable speed, the system cycles on and off too much - from clammy cold to too hot and back again.
the low seer recommendation is likely to do with repairs and total cost of ownership. as you move beyond ~14 seer2/15 seer1 the machine typically has to add logic somewhere, increasing repair costs a lot. the 14 seer2 models are incredibly simple if you pull the panel and look inside - just a few relays, the start capacitor, almost nothing to them. they're so simple they can be repaired with generic (!) parts in many cases. machines with higher seer end up with little computers in them - more parts to fail, SOFTWARE, harder troubleshooting, no generic repairs

your point about balancing cost to own with energy cost is well taken

AC output ratings are normalized - all else being equal a 14 vs. 18 seer unit will have the same output, just a larger electricity input for the 14 seer

re: vancouver BC - in the pnw we're lucky in that summer humidity is NOT a concern and can be pretty much ignored for AC sizing purposes. oversizing AC is thus less of a problem than most parts of the country
My understanding is the "Heat Dome" was humid as well as hot? Vancouver is a wet city, any time of year, so I am pretty sure they do a fairly humid heat, when it gets hot (London England is the same).

Pacific Northwest has very low energy costs, I understand -- as low as some of the south-eastern states.
I don't think it's necessarily fair to say that more complex electronics means more to go wrong. My 1986 Alfa Romeo has very simple electronics, but they are not very reliable. It's cheap to fix if you can DIY, but hunting down bad grounds and loose connectors is annoying and time consuming. It's expensive if you have to pay someone an hourly rate to do it. My 2020 Subaru has very complex electronics, but it's extremely reliable. Integrated circuits, computers, and software are "complex" but they fail a lot less often than a "simple" large capacitor. There are actually more electronic comments that might need replacing on the Alfa because there are more user-replaceable parts. If a modern ECU fails, you just replace the ECU. If an 80s ECU fails, you are probably getting out the multimeter and trying to replace individual bad components.

On the HVAC side, what kills electronics tends to be vibration and heat. A modern variable speed unit outputs a lot less of that. The real problem with the modern high-efficiency units is that the manufacturers grossly overcharge for them. For example, the Carrier smart thermostat is a $1,000 item if you need a replacement. Generic smart-thermostats are 1/5th that price. It's purely a case of Carrier overcharging for replacement parts rather than a fundamental aspect of a complex design. I also think early variable units gave variable units generally a bad name. New tech often has kinks that need to be worked out.
z0r
Posts: 272
Joined: Sat Nov 10, 2012 12:50 am

Re: Heat pump sizing and brands?

Post by z0r »

Valuethinker wrote: Tue Jun 04, 2024 11:41 am My understanding is the "Heat Dome" was humid as well as hot? Vancouver is a wet city, any time of year, so I am pretty sure they do a fairly humid heat, when it gets hot (London England is the same).

Pacific Northwest has very low energy costs, I understand -- as low as some of the south-eastern states.
so - I've actually not lived in vancouver bc, just portland seattle eugene, and I think I was wrong about vancouver. I looked at historical weather for last august and vancouver was a clear outlier, it was muggy. the others were not and muggy heat is extremely rare for the other i5 corridor population centers

vancouver https://www.wunderground.com/history/mo ... ate/2023-8

vs

portland, typical of the other three (portland seattle eugene) https://www.wunderground.com/history/mo ... ate/2023-8

more general trends can be seen on this site, it's fantastic, look at the "muggy %", and yeah it has vancouver at 2% vs. the others at 1%, something's going on. still, 2%?

https://weatherspark.com/y/472/Average- ... Year-Round
Topic Author
NYCaviator
Posts: 2334
Joined: Sat Apr 09, 2016 5:06 pm
Location: NYC

Re: Heat pump sizing and brands?

Post by NYCaviator »

Thanks for all the replies. After doing more research, I'm leaning towards replacing with a traditional A/C and natural gas furnace at the highest SEER2 that I can get. I am all for the lower environmental impact (theoretically) of the heat pump, but I don't think the ducted technology is quite there yet in the US. The units cost more to install, I'm not sure I'll see any savings on the monthly bill based on our electric/gas prices, and getting parts/service could be a hassle when a lot of the HVAC companies don't have much experience with heat pumps. It seems like it could be more of a hassle at the end of the day.
Pdxnative
Posts: 1039
Joined: Sat Nov 07, 2015 1:17 pm

Re: Heat pump sizing and brands?

Post by Pdxnative »

Did you look into a dual fuel system?

Do some YouTube searching on that. You can use a heat pump as an AC unit that heats in shoulder seasons, with your gas furnace as backup heat and air handler. Then you don’t need to size the heat pump for the coldest days because your furnace can kick on. (You can set a temp where the aux heat kicks in).

We ended up doing that due to some weird constraints in our situation, and with the thinking we could arbitrage electricity vs gas prices. (Our prices are comparable to yours).

After tax credits a cold climate heat pump was only a few thousand more than an AC.

We end up never using the 95% efficient gas furnace for heat and our energy costs are about 25% lower over the months needing heat. Part of that I think is because the coldest hours of the day are also the cheapest electricity for us (nighttime and we have a time of use plan).

I’m skeptical that there aren’t highly qualified heat pump installers in NYC, it’s just a matter of finding them. I know a ton of people with heat pumps and they’ve been very durable.

ETA: we have a ducted system btw. I don’t agree at all with your comment that ducted heat pumps aren’t there yet in the US. The US *brands* have been slow but there are plenty of great cold climate HP options available in the US.
Pdxnative
Posts: 1039
Joined: Sat Nov 07, 2015 1:17 pm

Re: Heat pump sizing and brands?

Post by Pdxnative »

Here’s a video on dual fuel (just happens to be one I’ve watched, there are plenty of others):

https://youtu.be/T_9P3Dn7is0?si=Smk-gJqpJLoJEL8l
z0r
Posts: 272
Joined: Sat Nov 10, 2012 12:50 am

Re: Heat pump sizing and brands?

Post by z0r »

if you're ok fiddling with energy prices and the setting correct switch over temp from heat pump to furnace you might consider dual fuel. see if you can get a quote where you get furnace+ac and then ask if you can get the same quote but switch the AC to the heat pump part #. not a fancy cold climate heat pump, just a regular one in the same frame

many AC product lines are now available as either straight cool or heat pump, with a price delta of $500-1000, and the install procedure is the same other than another low voltage wire and setting up the thermostat, just swap the part #. this would allow you to use the heat pump in moderate temps, give some slight redundancy, and could have a quick payoff (only using the heat pump in its high efficiency regime). probably won't get a tax credit but it could make sense anyway

product line example would be goodman gsx14 (straight cool) vs. gsz14 (heat pump)
TravellingTechOnFire
Posts: 500
Joined: Mon Nov 21, 2022 9:54 am

Re: Heat pump sizing and brands?

Post by TravellingTechOnFire »

NYCaviator wrote: Tue Jun 04, 2024 8:13 pm Thanks for all the replies. After doing more research, I'm leaning towards replacing with a traditional A/C and natural gas furnace at the highest SEER2 that I can get. I am all for the lower environmental impact (theoretically) of the heat pump, but I don't think the ducted technology is quite there yet in the US. The units cost more to install, I'm not sure I'll see any savings on the monthly bill based on our electric/gas prices, and getting parts/service could be a hassle when a lot of the HVAC companies don't have much experience with heat pumps. It seems like it could be more of a hassle at the end of the day.

I think it would definitely be worthwhile to get a significant handful of quotes from authorized Mitsubishi heat pump dealers. AFAIK, these authorized dealers enable a 12 year warranty. This is a bigger decision than just "I'm going to use a little bit of fossil fuel today", but is rather "I have the chance to either continue burning fossil fuel for the next couple of decades, or not". The benefit of a heat pump can potentially be improved even further with solar now or in the future, along with PHEV or EV. The technologies all complement one another. Overall, the switch to heat pump needs to be viable i.e. *reasonably* cost effective. It does not, IMO, need to be cheaper.

Personally, I would gladly pay the same cost over time to provide all of our energy with solar in the form of PHEV's, EV's, heat pumps, induction stoves, all electric appliances, etc knowing that I have completely eliminated the use of fossil fuel for decades.

In my experience, 100% electric along with solar ends up being quite a massive savings vs burning fossil fuels for decades(whether in the home, cars, lawn equipment etc). It's a huge hedge against inflation to have 100% of ones energy costs covered indefinitely throughout retirement.

Paying a lot of money on purpose to ensure the continued burning of fossil fuels for decades seems like a bizarre option in todays world.
dalbright
Posts: 528
Joined: Sun Oct 21, 2018 6:23 am

Re: Heat pump sizing and brands?

Post by dalbright »

BirderInTraining wrote: Mon Jun 03, 2024 12:47 pm I live in zone 8. My house is about 2850 sq ft and has 3 ac/heat pump units (because of the unusual layout of the house). The house is 41 years old. The original units were Carrier. The first one to go was the one for the upstairs bedrooms. It quit after 27 years of excellent service with regular maintenance. The second one was replaced last August, after 40 years of service. I chose to replace it because it had a leak and the refrigerant it needed is now very expensive and I wanted a more efficient unit. The third unit is still going strong after 41 years. This is by way of saying that Carrier knows a thing or two about heat pumps. Though, the various contractors who came out to bid on the new unit last year all said "they don't make 'em like they used to anymore." But they were not selling Carrier.

Because of size limitations of the "closet" that houses the air handler, the only unit that would fit was Mitsubishi. In the end, the contractor installed a unit from a new-ish venture between Trane and Mitsubishi Electric. (Moral of the story: google the model numbers they will provide on the bid to make sure you are getting what you think are getting.) Amazingly I went with the lowest bidder (they were highly recommended by a friend) who was offering to install what turned out to be the best equipment of all the bids. (Google the model numbers of all the bids you get and you will see what they retail for. It will give you a good idea of quality (it often correlates highly with price, but you know that already) and how much the installer is hoping to make in labor/profit.) Before you accept a bid look up the SEER numbers. If you get a unit with (if I remember correctly) a SEER of 18 or higher, and you owe federal taxes at the end of the year, you will get a $2,000 tax credit. I also had the unit inspected by my city and qualified for an $800 rebate. I did all the legwork for the rebate and tax credit; it was easy to do. The new unit is a 1.5 ton and I paid $9,015, before the rebate and tax credit. I am over the moon with the new unit. It is so quiet and works really well. We had a polar vortex in January and the unit performed flawlessly. I had bids of over $17K for far worse equipment, so be sure to talk to friends and get several bids.

The Japanese know a thing or two about heat pumps. The unit I got has "hyper heat" (not sure about the name of the feature). Basically, when it gets really cold outside it does not fire up electrical coils and blows air over them (super expensive supplemental heat). I don't understand the technology but the installer showed me the top of the air handler and pointed out that there are no coils because it does not need them.

Last, as others have mentioned before, do not install a larger unit than what is there already. It will cool the rooms too quickly and won't pull out enough humidity and you will always be uncomfortable. Good luck.
Did you install the dual fuel intelli-heat? Or was this just the mitsubishi air handler? If you went the intell-heat route I would love to hear your thoughts on it as i've been leaning that way when my r-22 trane says its had enough someday (hopefully never).
Valuethinker
Posts: 49659
Joined: Fri May 11, 2007 11:07 am

Re: Heat pump sizing and brands?

Post by Valuethinker »

alfaspider wrote: Tue Jun 04, 2024 12:26 pm

I don't think it's necessarily fair to say that more complex electronics means more to go wrong. My 1986 Alfa Romeo has very simple electronics, but they are not very reliable. It's cheap to fix if you can DIY, but hunting down bad grounds and loose connectors is annoying and time consuming. It's expensive if you have to pay someone an hourly rate to do it. My 2020 Subaru has very complex electronics, but it's extremely reliable. Integrated circuits, computers, and software are "complex" but they fail a lot less often than a "simple" large capacitor. There are actually more electronic comments that might need replacing on the Alfa because there are more user-replaceable parts. If a modern ECU fails, you just replace the ECU. If an 80s ECU fails, you are probably getting out the multimeter and trying to replace individual bad components.

On the HVAC side, what kills electronics tends to be vibration and heat. A modern variable speed unit outputs a lot less of that. The real problem with the modern high-efficiency units is that the manufacturers grossly overcharge for them. For example, the Carrier smart thermostat is a $1,000 item if you need a replacement. Generic smart-thermostats are 1/5th that price. It's purely a case of Carrier overcharging for replacement parts rather than a fundamental aspect of a complex design. I also think early variable units gave variable units generally a bad name. New tech often has kinks that need to be worked out.
Good points on electronics. Thank you.

Normally reliability in electronics is "bathtub curve". i.e. U shaped with time on the x axis.

Early failures due to faults in manufacturing (generally too much crammed into too small a space).

Subsequently runs very well until exceeds design life. Then total failure - or the components are no longer available!
Topic Author
NYCaviator
Posts: 2334
Joined: Sat Apr 09, 2016 5:06 pm
Location: NYC

Re: Heat pump sizing and brands?

Post by NYCaviator »

Pdxnative wrote: Tue Jun 04, 2024 9:36 pm I’m skeptical that there aren’t highly qualified heat pump installers in NYC, it’s just a matter of finding them. I know a ton of people with heat pumps and they’ve been very durable.

ETA: we have a ducted system btw. I don’t agree at all with your comment that ducted heat pumps aren’t there yet in the US. The US *brands* have been slow but there are plenty of great cold climate HP options available in the US.
Most of the installers I've talked to are very familiar with mini-split systems (which have been around for a long time) but are less familiar with the ducted systems. That's what my biggest concern is. I already have a ducted system, so I don't want to go mini-split.

Other that Mitsubishi, what are reliable cold-climate heat pumps? While it's rare, it does occasionally dip below 0 at night here when it's really cold.

I'm getting some quotes for a Mitsubishi system, but anecdotally, I've been told parts can be hard to source due to it being a newer product and service options are limited to Mitsu contractors who work on ducted (not just ductless) systems.

For those that suggested dual fuel, I'll take a look at that, but I'd rather just go all-in if I'm doing a heat pump and get a cold climate, unless the pricing is similar.
Pdxnative
Posts: 1039
Joined: Sat Nov 07, 2015 1:17 pm

Re: Heat pump sizing and brands?

Post by Pdxnative »

NYCaviator wrote: Wed Jun 05, 2024 7:27 am
Pdxnative wrote: Tue Jun 04, 2024 9:36 pm I’m skeptical that there aren’t highly qualified heat pump installers in NYC, it’s just a matter of finding them. I know a ton of people with heat pumps and they’ve been very durable.

ETA: we have a ducted system btw. I don’t agree at all with your comment that ducted heat pumps aren’t there yet in the US. The US *brands* have been slow but there are plenty of great cold climate HP options available in the US.
Most of the installers I've talked to are very familiar with mini-split systems (which have been around for a long time) but are less familiar with the ducted systems. That's what my biggest concern is. I already have a ducted system, so I don't want to go mini-split.

Other that Mitsubishi, what are reliable cold-climate heat pumps? While it's rare, it does occasionally dip below 0 at night here when it's really cold.

I'm getting some quotes for a Mitsubishi system, but anecdotally, I've been told parts can be hard to source due to it being a newer product and service options are limited to Mitsu contractors who work on ducted (not just ductless) systems.

For those that suggested dual fuel, I'll take a look at that, but I'd rather just go all-in if I'm doing a heat pump and get a cold climate, unless the pricing is similar.
Bosch, Fujitsu, Daikin have good reputations. But even Carrier has good cold climate options now (I think Midea makes some of those for them). Daikin and carrier supply chains are good in my area, not sure about nyc. Many of the mini-split outdoor units can be used with ducted systems too.

The advantage of dual fuel for you would be not needing to replace your furnace, which would also act as the air handler for the HP. And, with gas as your aux heat you wouldn’t have as much pressure to size up your HP for the (rare) coldest days. Chances are you’d end up using gas heat rarely if at all.
Post Reply