Central AC replacement decision

Questions on how we spend our money and our time - consumer goods and services, home and vehicle, leisure and recreational activities
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Central AC replacement decision

Post by dodecahedron »

See my update six years later which I posted on page 2 here

Our Trane unit is 23 years old and still uses Freon. We have it serviced annually and it works just fine, but when the HVAC service guy was here today, he noted its age and the fact that it is statistically overdue for replacement. We have had an exceptionally mild and comfortable summer and as a result our HVAC company has a large amount of excess capacity at the moment, because nobody is clamoring for repairs or new installations, so they are offering a 5% discount from their usual pricing. I also got them to agree to give me another 5% off for paying cash (rather than taking them up on their 0%-free financing for a year offer.)

(It should be noted that we really like this company and they have a great reputation as the being the best around, so I am not inclined to get bids from other contractors. Not only did they install our Trane unit in 1991, they installed a new Lennox Signature high-efficiency furnace a few years ago, converting our heat from oil to natural gas in the process, which has saved us a lot of money and all kinds of hassles.)

Of course, we *could* wait until disaster strikes before bothering to replace the AC unit, but environmentally conscious daughter pointed out that waiting until the Freon starts leaking would be an environmental insult. Also the most likely failure scenario would be in the midst of a heat wave, when everybody else is clamoring for new units and we would not likely get the price concessions currently being offered.

Our current Trane was theoretically rated at SEER 10 at the time we bought it in 1991, which was apparently state of the art at the time. Currently debating between

Lennox Signature XC17 (single stage, SEER up to 18.0) $6,450
or
Lennox Signature XC21 (dual stage, SEER 21.10) $7,350

Supposedly the more expensive one will save an extra ~$50/year in average year based on national statistics and current energy prices. So pretty long payback period on the additional $900 up front cost, unless energy prices rise a lot in the future. Also, we have amazingly nice summers here in Upstate NY (compared to other places I have lived, including DC, Houston, LA, Philly, and Boston), so we have a lot less usage than many other parts of the country.

Plus the dual stage XC21 is considerably noisier (69dB for the XC21 vs. 62dB for the XC17, though both of them are considerably quieter than our current unit.)

Thoughts or advice welcome!
Last edited by dodecahedron on Wed Jul 29, 2020 8:33 pm, edited 3 times in total.
User avatar
Ged
Posts: 3923
Joined: Mon May 13, 2013 1:48 pm
Location: Roke

Re: Central AC replacement decision

Post by Ged »

How far upstate? I lived in Syracuse 1975-1992. Maybe one week a year I felt uncomfortably warm. I didn't have AC either in my house or in my cars.

I spent the AC money on 4WD and snow removal equipment.

Oh, and by the way Freon is just a trademarked name for a class of chemical compounds used as refrigerants. There are others, such as Genetron. Some are harmful to the ozone layer, others not so much. The number of the Freon is a code for it's chemical structure. If you know the number you can figure out the environmental impact.

From Wikipedia.

The R-# numbering system was developed by DuPont corporation (which owns the Freon trademark) and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. The meaning of the codes is as follows:

Subtracting 90 from the concatenated numbers of carbon, hydrogen and fluorine atoms, respectively gives the assigned R#.
Remaining bonds not accounted for are occupied by chlorine atoms.
A suffix of a lower-case letter a, b, or c indicates increasingly unsymmetrical isomers.
As a special case, the R-400 series is made up of zeotropic blends (those where the boiling point of constituent compounds differs enough to lead to changes in relative concentration because of fractional distillation) and the R-500 series is made up of so-called azeotropic blends. The rightmost digit is assigned arbitrarily by ASHRAE, an industry organization.
davebarnes
Posts: 542
Joined: Wed Jan 02, 2008 7:06 pm
Location: Berkeley, Denver, Colorado USA

Diminishing returns

Post by davebarnes »

I would be looking at SEER 14.
A lot lower in price.
You need to run some numbers
A nerd living in Denver
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

Ged wrote:How far upstate? I lived in Syracuse 1975-1992. Maybe one week a year I felt uncomfortably warm. I didn't have AC either in my house or in my cars.

I spent the AC money on 4WD and snow removal equipment.
Syracuse, huh? Isn't that where they *invented* air conditioning? Carrier HQ, right? (I used to imagine that Syracuse just bottled up their cool air and shipped it to other places around the country!)

Seriously, I am to the southeast of Syracuse, more east than south, and not near a major lake the way Syracuse is. Also, there has been a general warming trend in recent decades since you lived in Upstate NY. When we moved here in 1989, our real estate agents thought it was a bit silly that my husband refused to even look at any houses unless either had central AC or at least the ductwork in place to make it easy to install central AC. Now--at least in our housing price bracket--central AC is pretty much universal. It is pretty nice a lot of the time, but in a brick colonial with slate roof and cathedral ceilings and a bunch of skylights, it can get pretty warm on many summer days.

Thanks for all the information about coolant composition. The coolant the Lennox units use is R410A, which didn't mean anything to me before, but I will research it now.
Mingus
Posts: 696
Joined: Fri Apr 19, 2013 2:25 pm

Re: Central AC replacement decision

Post by Mingus »

If your summers are mild, there is no reason to replace a well functioning unit with something new. It might have another 23 years in it.
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Diminishing returns

Post by dodecahedron »

davebarnes wrote:I would be looking at SEER 14.
A lot lower in price.
You need to run some numbers
Hmm, the quote for the SEER 14 model was $5,900 installed, which is not all that much cheaper than the SEER 17. (And SEER 14 was the noisiest of the three, at 70dB). I think the reason it wasn't much cheaper is that Lennox seems to have an excess supply of the higher end models and is giving manufacturer rebates on them. No rebate on the 14.
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

Mingus wrote:If your summers are mild, there is no reason to replace a well functioning unit with something new. It might have another 23 years in it.
Certainly a tempting idea, especially because this summer has been exceptionally mild. This is what I was hoping to hear.
User avatar
Aptenodytes
Posts: 3768
Joined: Tue Feb 08, 2011 8:39 pm

Re: Central AC replacement decision

Post by Aptenodytes »

In general you want to concentrate your efficiency investments in your heating system, not your cooling system. Where you live you get far better returns there.

So I'd agree with the sentiment not to aim too high. You can get better return elsewhere (insulation, windows, caulking leaks, new furnace, etc.).

Maybe you are maxed out on all those other savings. I would still lean toward the less expensive unit or just letting the old one chug along.
john94549
Posts: 4638
Joined: Tue Jul 26, 2011 8:50 pm

Re: Central AC replacement decision

Post by john94549 »

Funny story. We're in Northern California, in the area known for "hot" weather. About five years ago, the A/C just died. As it was original equipment (from 1978) I assumed the worst. We just lived with no A/C for those five years. Finally came to our senses (after the temp hitting plus 100 for a week or so) and called the HVAC folks. Guy came out, flipped the circuit breaker, the A/C came right back on. I had no idea where the circuit breaker was, or that it had flipped.

The service person noted our system was a tad dated, but provided the old adage: "if it ain't broke". My wife's sister and brother-in-law dropped low six figures to replace their system in Vacaville.
Gill
Posts: 6706
Joined: Sun Mar 04, 2007 8:38 pm
Location: Florida

Re: Central AC replacement decision

Post by Gill »

john94549 wrote: My wife's sister and brother-in-law dropped low six figures to replace their system in Vacaville.
I hope you meant low five figures...
Gill
Cost basis is redundant. One has a basis in an investment | One advises and gives advice | One should follow the principle of investing one's principal
User avatar
stickman731
Posts: 327
Joined: Sun Jan 01, 2012 10:42 am
Location: New Jersey

Re: Central AC replacement decision

Post by stickman731 »

Remember to search for state and utility company repairs. Well worth it in NJ for me. Four years ago, I essentially got a free hvac unit from NJ.
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

stickman731 wrote:Remember to search for state and utility company repairs. Well worth it in NJ for me. Four years ago, I essentially got a free hvac unit from NJ.
I am mystified/clueless as to how you pulled this off? Could you explain?
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

Aptenodytes wrote:In general you want to concentrate your efficiency investments in your heating system, not your cooling system. Where you live you get far better returns there.

So I'd agree with the sentiment not to aim too high. You can get better return elsewhere (insulation, windows, caulking leaks, new furnace, etc.).

Maybe you are maxed out on all those other savings. I would still lean toward the less expensive unit or just letting the old one chug along.
We already have a (fabulous!) new Lennox Signature furnace, purchased a few years ago from the same HVAC company. One of the best decisions we ever made. We converted from oil to gas and had the underground oil tank (a potential major environmental disaster if it had developed a leak) drained, decommissioned, and certified as environmentally hazard-free by the state testing lab. New high energy natural gas furnace saves money on fuel and is massively less temperamental than the old oil furnace was.

Still tempted to let the old AC chug along, though, My late husband was a polar bear--he loved keeping the house cool. Me, really not so much. (Grew up in DC without air conditioning.) Really out to consider a whole-house fan and opening windows more. (Not an option while late husband was alive, due to allergies.) House is often quite warm in the evenings inside even when it is lovely outside (because the bricks and slate have been absorbing sun's heat all day.)
User avatar
Ged
Posts: 3923
Joined: Mon May 13, 2013 1:48 pm
Location: Roke

Re: Central AC replacement decision

Post by Ged »

dodecahedron wrote:
Ged wrote:How far upstate? I lived in Syracuse 1975-1992. Maybe one week a year I felt uncomfortably warm. I didn't have AC either in my house or in my cars.

I spent the AC money on 4WD and snow removal equipment.
Syracuse, huh? Isn't that where they *invented* air conditioning? Carrier HQ, right? (I used to imagine that Syracuse just bottled up their cool air and shipped it to other places around the country!)

Seriously, I am to the southeast of Syracuse, more east than south, and not near a major lake the way Syracuse is. Also, there has been a general warming trend in recent decades since you lived in Upstate NY. When we moved here in 1989, our real estate agents thought it was a bit silly that my husband refused to even look at any houses unless either had central AC or at least the ductwork in place to make it easy to install central AC. Now--at least in our housing price bracket--central AC is pretty much universal. It is pretty nice a lot of the time, but in a brick colonial with slate roof and cathedral ceilings and a bunch of skylights, it can get pretty warm on many summer days.

Thanks for all the information about coolant composition. The coolant the Lennox units use is R410A, which didn't mean anything to me before, but I will research it now.
Yes, Carrier did have a big part in the development of air conditioning. I used some of their industrial equipment in my work at one time.

Ductwork isn't quite as important as it used to be for AC installation thanks to the increasing improvement of ductless mini-split systems. My guess these are going into quite a few older homes. I put one of these in my garage recently to make the shop I have installed there usable year round. I didn't want to tie it into my house duct system for obvious reasons.

You have probably figured out by now R410a does not appreciably contribute to ozone depletion. Interestingly this is not a Freon as it was developed by Allied-Signal (in Buffalo NY!), not DuPont. It's sold under a variety of trade names like Genetron and Puron, but not Freon. So no guilt if it leaks out.

I still have friends in the Syracuse area, and they tell me the amount of snow has decreased significantly. Not last year though; that was in line with historic averages. I lucked out moving in 1992. The 1992-1993 winter was the all time record at 192 inches.
Valuethinker
Posts: 41163
Joined: Fri May 11, 2007 11:07 am

Re: Central AC replacement decision

Post by Valuethinker »

dodecahedron wrote:Our Trane unit is 23 years old and still uses Freon. We have it serviced annually and it works just fine, but when the HVAC service guy was here today, he noted its age and the fact that it is statistically overdue for replacement. We have had an exceptionally mild and comfortable summer and as a result our HVAC company has a large amount of excess capacity at the moment, because nobody is clamoring for repairs or new installations, so they are offering a 5% discount from their usual pricing. I also got them to agree to give me another 5% off for paying cash (rather than taking them up on their 0%-free financing for a year offer.)

(It should be noted that we really like this company and they have a great reputation as the being the best around, so I am not inclined to get bids from other contractors. Not only did they install our Trane unit in 1991, they installed a new Lennox Signature high-efficiency furnace a few years ago, converting our heat from oil to natural gas in the process, which has saved us a lot of money and all kinds of hassles.)

Of course, we *could* wait until disaster strikes before bothering to replace the AC unit, but environmentally conscious daughter pointed out that waiting until the Freon starts leaking would be an environmental insult. Also the most likely failure scenario would be in the midst of a heat wave, when everybody else is clamoring for new units and we would not likely get the price concessions currently being offered.
I am of the school that for mission critical equipment (my family lives on Lake Ontario, AC in summer is mission critical) like AC, Cars etc. you don't wait until they go wrong to replace.

You exploit market opportunities to replace a low price, when they occur (as long as you don't have to borrow to do that).
Our current Trane was theoretically rated at SEER 10 at the time we bought it in 1991, which was apparently state of the art at the time.
Yup. And it's actual SEER will have depreciated.
Currently debating between

Lennox Signature XC17 (single stage, SEER up to 18.0) $6,450
or
Lennox Signature XC21 (dual stage, SEER 21.10) $7,350

Supposedly the more expensive one will save an extra ~$50/year in average year based on national statistics and current energy prices. So pretty long payback period on the additional $900 up front cost, unless energy prices rise a lot in the future. Also, we have amazingly nice summers here in Upstate NY (compared to other places I have lived, including DC, Houston, LA, Philly, and Boston), so we have a lot less usage than many other parts of the country.
OK you don't pay national energy prices? Niagara-Mohawk is your utilitiy? (the British owner is National Grid Co?). You pay closer to double-- 20c a kwhr peak? When that nuclear plant upstate shuts, the price of electricity in upstate NY will go *up*. Competing with southern Ontario for summer power, and Ontario's population growth remains robust (warmest part of Canada, rather than coldest part of America ;-)). Electricity consumption downstate continues to grow and grow, with the success of the greater NYC economy.

Hydro Quebec is also maxxing out on its existing capacity, and phasing out (phased out?) Gentilly nuclear power plants. The next phase of James Bay hydro, if it ever gets built, will be *expensive*. They will need downstate NY (a power link is being built under Lake Champlain) to sign up to long term power contracts at high prices. Ditto for Ontario Power Generation as the nukes (Pickering then Bruce) phase out-- they will need more gas fired electricity, and they have no real substitute for their nuclear fleet (c. 60% of all kwhr generated).

So my forecast is for higher electricity prices in the north west part of the north east ;-).

And yes, the summers are getting hotter. At least in Greater Toronto Area, the urban heat island effect is kicking in big time (used to have a January peak, now a summer peak demand). That's aside from any other issues.
Plus the dual stage XC21 is considerably noisier (69dB for the XC21 vs. 62dB for the XC17, though both of them are considerably quieter than our current unit.)

Thoughts or advice welcome!
The actual improvement from 18 to 21 is small*. I think the noise probably tips it in favour of the more quiet one (although at those levels it is a slight difference). The key is multiple speeds. The issue in that part of North America is humidity, and a one speed AC just cycles on, gets the temperature down but not the humidity.

http://en.wikipedia.org/wiki/Seasonal_e ... ency_ratio
Substantial energy savings can be obtained from more efficient systems. For example by upgrading from SEER 9 to SEER 13, the power consumption is reduced by 30% (equal to 1 − 9/13). It is claimed that this can result in an energy savings valued at up to US$300 per year depending on the usage rate and the cost of electricity.
The actual energy saving from 18 to 21 is small. (21-18)/ 21 (? wikipedia should it not be / 18?) is 1/7th or about 14%.
dolphinsaremammals
Posts: 2094
Joined: Tue Jul 22, 2014 4:18 pm

Re: Central AC replacement decision

Post by dolphinsaremammals »

Valuethinker wrote: When that nuclear plant upstate shuts, the price of electricity in upstate NY will go *up*.
Any place nuclear is being shut down will see a substantial increase in electrical costs (and pollution, because wind and solar can't possibly replace the amount of energy from nuclear, so it has to come from dirtier sources)
User avatar
stickman731
Posts: 327
Joined: Sun Jan 01, 2012 10:42 am
Location: New Jersey

Re: Central AC replacement decision

Post by stickman731 »

dodecahedron wrote:
stickman731 wrote:Remember to search for state and utility company repairs. Well worth it in NJ for me. Four years ago, I essentially got a free hvac unit from NJ.
I am mystified/clueless as to how you pulled this off? Could you explain?
In NJ, they had a program called CoolAdvantage coupled with a detailed home energy audit. (http://www.njcleanenergy.com/misc/resid ... promotions). My house was built in 1957 and had upgrades over the years. It still qualified for the max. Funds are now limited due to Christie cutbacks and qualification is hard I understand.

I would highly recommend googling "Your State" HVAC rebates. My contractor turned me on to it so I am forever thankful.
denovo
Posts: 4533
Joined: Sun Oct 13, 2013 1:04 pm

Re: Central AC replacement decision

Post by denovo »

dodecahedron wrote:
Mingus wrote:If your summers are mild, there is no reason to replace a well functioning unit with something new. It might have another 23 years in it.
Certainly a tempting idea, especially because this summer has been exceptionally mild. This is what I was hoping to hear.
If it ain't broke, don't fix it.
"Don't trust everything you read on the Internet"- Abraham Lincoln
Call_Me_Op
Posts: 7984
Joined: Mon Sep 07, 2009 2:57 pm
Location: Milky Way

Re: Diminishing returns

Post by Call_Me_Op »

dodecahedron wrote:
davebarnes wrote:I would be looking at SEER 14.
A lot lower in price.
You need to run some numbers
Hmm, the quote for the SEER 14 model was $5,900 installed, which is not all that much cheaper than the SEER 17. (And SEER 14 was the noisiest of the three, at 70dB).
The noise of what? Both the compressor and blower should be well-isolated from living spaces.
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein
Valuethinker
Posts: 41163
Joined: Fri May 11, 2007 11:07 am

Re: Central AC replacement decision

Post by Valuethinker »

dolphinsaremammals wrote:
Valuethinker wrote: When that nuclear plant upstate shuts, the price of electricity in upstate NY will go *up*.
Any place nuclear is being shut down will see a substantial increase in electrical costs
(My father built nuclear reactors in Ontario). The reason nuclear power is cheap is because the huge costs (then) of building it have been written off (with a few exceptions, the 120 or so operating reactors in North America were all built in the 60s or 70s and started operation in the 1970s or 80s). So we are in essence paying the marginal cost of nuclear power (fuel, operations & maintenance plus heavily written down capital costs) rather than the total cost (waste disposal was never factored into the costs).

It's an artefact of historic cost accounting. If you used replacement cost accounting (or even current cost) you'd have far larger capital bases and far higher rates (or the nuclear generators would be reporting thumping losses). Nuclear is 'cheap' because the plants were built a long time ago.

You'll have noted a number of singleton reactors being shut down for cost reasons (Vermont Yankee, one in Wisconsin) despite having written off the capital costs long ago (ie they just need to cover Operations & Maintenance, and fuel). The nuclear operators are finding that the increasing costs of maintenance and renewal are just not justified in an environment of cheap natural gas. This falls worst on single units (no site economies on O&M) which are older.
(and pollution, because wind and solar can't possibly replace the amount of energy from nuclear, so it has to come from dirtier sources)

Actually they can. In the UK for example, onshore wind is cheaper than new nuclear. Ireland it is cheaper than gas (European natural gas prices are much higher than North America). Offshore wind (which is more reliable in terms of hours of generation/ total potential) is equivalently expensive to new nuclear. We know this, because we know what the Feed In Tariff prices are for the different forms, and we know what the UK government has guaranteed to EDF to build the new nukes-- Hinkley C, Sizewell C. (roughly speaking £95/ MWH ie 9.5 pence/ khwr = c. 16 cents = twice current electricity wholesale price).

The cost of new nukes, by the people who are actually *doing* them, is forbidding (in developed countries; China may be a different matter). Both the Finnish plant and the Flamanville, both AREVA's EPR (3rd gen) design, are way behind and way over budget. If you look at the costs of new plants MIT sketched out in 2002, the estimates since then have x2 to x3.

You will never get another new nuke in a 'merchant' (ie competitive power pool) environment. They will all be built where electricity regulation is traditional and the utilities are vertically integrated, so the costs can be dumped on the final users. It's too much risk otherwise-- the Credit Rating agencies would eat them alive.

Solar cells the price falls have been remarkable, and yet they continue. We are approaching grid parity in a number of places (somewhere like Italy, you must already be there-- Italian electricity is c. 30 cents Euro a kwhr retail). Hawaii you would be there already (because you are competing with fuel oil).

The issue with renewables is about intermittency and what you do for backup. Whether it is hydro pumped storage, a continent-spanning grid (so the sun is shining or the wind is blowing *somewhere*), gas fired backup or something else (which doesn't exist yet: hydrogen hydrolysis and fuel cells?). Of course nuclear has an issue there too (nuclear plants must produce 24/7, it's not simple just to take them 'off the grid') so you haven't escaped the problem of the daily variation in power demand. If you have more nuclear capacity than your baseload (say 40-60% of your peak) then it gets *very* expensive to have that capacity-- you can wind up paying someone else to take your electricity (this is what happens in Ontario at some times of the night, apparently).

And where and when CCS comes in, if it does. The cost issues (Kemper!) are really forbidding (although I believe them to be solvable-- the science works, this is just finding ways to do it cheaper and cleverer).
Valuethinker
Posts: 41163
Joined: Fri May 11, 2007 11:07 am

Re: Central AC replacement decision

Post by Valuethinker »

dolphinsaremammals wrote:
Valuethinker wrote: When that nuclear plant upstate shuts, the price of electricity in upstate NY will go *up*.
Any place nuclear is being shut down will see a substantial increase in electrical costs
It occurs to me we could both be wrong on this, in that it's not a blanket assertion one can make.

If the electricity is set by pool price, then it's not the zero feed in prices that drive the price. The zero feed ins come from nuclear, wind, solar ie they *have* to sell, their power has to be taken by the grid.

What drives the price is the cost of the *marginal* generation-- the last plant to come into that time slot. Which will be gas or coal (probably gas). So it's the economics of the marginal plant (ie that only gets bid into the pool when prices are high) that matters, not the *average* plant.

The effect of nuclear being phased out is then (assuming nuclear is not a large percentage to start with) some increase in electricity prices during very low periods, but not overall. One would have to think through the pool price mechanism and the 'bid in' hierarchy (lowest cost first etc.).

I cannot for the life of me remember whether NY sets its power price via a pool, and if so which pool.
ericinri
Posts: 31
Joined: Thu Jan 24, 2013 6:31 am

Re: Central AC replacement decision

Post by ericinri »

I'm in the if it ain't broke don't fix it camp. But if you really want to do, I would get more estimates. You will never get payback on the seer 21 in your climate plus you are paying a lot for the Lenox name. There are only one or two compressor companies out there so you will fond the same parts inside most of these units.
For what it is worth, I just had a 13 seer unit installed for $2200. For 3-4 months of usage, I can't imagine how long it would take to payback the $4-5k price delta to what you were quoted.
sscritic
Posts: 21858
Joined: Thu Sep 06, 2007 8:36 am

Re: Diminishing returns

Post by sscritic »

Call_Me_Op wrote: The noise of what? Both the compressor and blower should be well-isolated from living spaces.
It depends. I leave my windows open; my close next door neighbor leaves his AC on all night. It may be isolated for him, but it is not isolated for me. I even have to close my window in my study to hear my Chinese soap operas, his compressor being right outside my window. That's my choice: roast or miss out on what's happening. It's not like my Chinese is so good that I can read lips.
Call_Me_Op
Posts: 7984
Joined: Mon Sep 07, 2009 2:57 pm
Location: Milky Way

Re: Diminishing returns

Post by Call_Me_Op »

sscritic wrote:
Call_Me_Op wrote: The noise of what? Both the compressor and blower should be well-isolated from living spaces.
It depends. I leave my windows open; my close next door neighbor leaves his AC on all night. It may be isolated for him, but it is not isolated for me. I even have to close my window in my study to hear my Chinese soap operas, his compressor being right outside my window. That's my choice: roast or miss out on what's happening. It's not like my Chinese is so good that I can read lips.
Sounds like you might need your own central AC system. :) I can't leave the windows open at my place because I never know when someone is going to blow-off loud fireworks.
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

ericinri wrote:I'm in the if it ain't broke don't fix it camp. But if you really want to do, I would get more estimates. You will never get payback on the seer 21 in your climate plus you are paying a lot for the Lenox name. There are only one or two compressor companies out there so you will fond the same parts inside most of these units.
For what it is worth, I just had a 13 seer unit installed for $2200. For 3-4 months of usage, I can't imagine how long it would take to payback the $4-5k price delta to what you were quoted.
Wow! $2,200 seems really low. In our case, installation involves removing an old system, draining no longer permitted coolant, replacing all the pipes running from outdoor unit to the utility room located quite a distance away (center of our home).
User avatar
Timoneer
Posts: 180
Joined: Sun Jan 01, 2012 9:41 pm

Re: Central AC replacement decision

Post by Timoneer »

dodecahedron wrote:Our Trane unit is 23 years old and still uses Freon. We have it serviced annually and it works just fine, but when the HVAC service guy was here today, he noted its age and the fact that it is statistically overdue for replacement. We have had an exceptionally mild and comfortable summer and as a result our HVAC company has a large amount of excess capacity at the moment, because nobody is clamoring for repairs or new installations, so they are offering a 5% discount from their usual pricing. I also got them to agree to give me another 5% off for paying cash (rather than taking them up on their 0%-free financing for a year offer.)

...
Thoughts or advice welcome!
I have a Trane AC that is 25 years old. Last year I asked the service tech whether it was due for replacement, and he replied that the Trane units of that vintage had incredible durability. Much better than units made today, from his experience. His opinion was to hold onto it as long as possible.

If it does finally give out during a heat wave, I will likely just buy one or two window units to tide me over until I can get a replacement installed.
Call_Me_Op
Posts: 7984
Joined: Mon Sep 07, 2009 2:57 pm
Location: Milky Way

Re: Central AC replacement decision

Post by Call_Me_Op »

Carrier SEER 13 multi-speed with Puron here, circa 2004. Very happy with the system in all respects.
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Diminishing returns

Post by dodecahedron »

sscritic wrote:
Call_Me_Op wrote: The noise of what? Both the compressor and blower should be well-isolated from living spaces.
It depends. I leave my windows open; my close next door neighbor leaves his AC on all night. It may be isolated for him, but it is not isolated for me. I even have to close my window in my study to hear my Chinese soap operas, his compressor being right outside my window. That's my choice: roast or miss out on what's happening. It's not like my Chinese is so good that I can read lips.
Consideration for neighbors is part of concern, since I never hear their unit (not even sure if they have one!) but I am sure they must hear ours, which is not far from their sleeping areas. It is most annoying for me when it goes on when I am in our wondrous backyard listening to birds, frogs, chirping insects, and babbling brook running through the ravine. They have a nice backyard too, and I imagine it must be annoying to hear our AC. Indoors with windows closed it is most noticeable when I am using my late husband's very nice study, since it is right outside, but I have a smaller study of my own in the center of the house and can't hear it much from there. I can't hear it at all from my bedroom.
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

Timoneer wrote:
dodecahedron wrote:Our Trane unit is 23 years old and still uses Freon. We have it serviced annually and it works just fine, but when the HVAC service guy was here today, he noted its age and the fact that it is statistically overdue for replacement. We have had an exceptionally mild and comfortable summer and as a result our HVAC company has a large amount of excess capacity at the moment, because nobody is clamoring for repairs or new installations, so they are offering a 5% discount from their usual pricing. I also got them to agree to give me another 5% off for paying cash (rather than taking them up on their 0%-free financing for a year offer.)

...
Thoughts or advice welcome!
I have a Trane AC that is 25 years old. Last year I asked the service tech whether it was due for replacement, and he replied that the Trane units of that vintage had incredible durability. Much better than units made today, from his experience. His opinion was to hold onto it as long as possible.

If it does finally give out during a heat wave, I will likely just buy one or two window units to tide me over until I can get a replacement installed.
I probably wouldn't even bother with that myself, come to think of it. Since I am an academic with flexible schedule in summers, I might just go visit relatives or friends or a country inn in the mountains. And heat waves don't tend to last that long in these parts anyway.
sscritic
Posts: 21858
Joined: Thu Sep 06, 2007 8:36 am

Re: Diminishing returns

Post by sscritic »

Call_Me_Op wrote: Sounds like you might need your own central AC system. :)
I have one, it's just that I am (pick one): too cheap to run it, too much of a boglehead to run it, or both (is there a difference?).
goblue100
Posts: 1237
Joined: Sun Dec 01, 2013 10:31 am

Re: Central AC replacement decision

Post by goblue100 »

dodecahedron wrote:
ericinri wrote:I'm in the if it ain't broke don't fix it camp. But if you really want to do, I would get more estimates. You will never get payback on the seer 21 in your climate plus you are paying a lot for the Lenox name. There are only one or two compressor companies out there so you will fond the same parts inside most of these units.
For what it is worth, I just had a 13 seer unit installed for $2200. For 3-4 months of usage, I can't imagine how long it would take to payback the $4-5k price delta to what you were quoted.
Wow! $2,200 seems really low. In our case, installation involves removing an old system, draining no longer permitted coolant, replacing all the pipes running from outdoor unit to the utility room located quite a distance away (center of our home).
I had to replace my 14 year old AC unit when the compressor seized. I had the option of replacing just the outside unit and staying on the older style Freon which would have cost ~ 2500 for a Carrier Performance Series 14 Seer unit. Option 2 was to go to the newer style refrigerant which involved replacing both the outside unit and the inside evaporator coil, for ~ 4500. I ended up going with option 2.

I would get a couple of more quotes, especially since you have the time and your AC is not out.
Financial planners are savers. They want us to be 95 percent confident we can finance a 30-year retirement even though there is an 82 percent probability of being dead by then. - Scott Burns
dickenjb
Posts: 2941
Joined: Tue Jan 05, 2010 1:11 pm
Location: Philadelphia PA

Re: Central AC replacement decision

Post by dickenjb »

Three generations of refrigerants:

CFCs - chlorinated, fluorinated hydrocarbons - very bad ODP (ozone depleting potential) R12

HCFCs - hydrogen containing chloro fluoro carbons - bad ODP R22

HFCs - hydrogen containing fluorocarbons - minimal ODP. R410a

The draw of the dual stage compressor unit is not the $50 a year in electricity savings which as you point out has a long payback. The draw is it can run on low and keep the temp in your house more even while doing a better job wringing out the humidity.
User avatar
walkabout
Posts: 639
Joined: Wed May 25, 2011 8:28 am
Location: Northern Alabama

Re: Central AC replacement decision

Post by walkabout »

I would recommend that you post questions about replacing your AC system here:

http://ths.gardenweb.com/forums/hvac/

If possible, be prepared to give model numbers, especially for the furnace that you already replaced. You will get good information, especially if tigerdunes answers.

One important factor is the compatibility between your existing furnace and the new AC. In order to get the advertised SEER rating (or close to it) the AC unit must be a good match with the furnace. The overall efficiency of the HVAC system depends on the the sum of the parts. Typically for a new HVAC system with AC, furnace, and coil each of these components is spec'd separately, but with an eye towards the building the best matching system possible. You don't want to pay extra to get a "better" component and then pair it with a "good" component. For example, if your furnace does not have a variable speed fan (true variable speed, not adjustable speed), then my guess is that you will not derive the kind of benefit that a two stage AC would provide. There is actually a way to look up what the good matches would be for your furnace and coil. tigerdunes does this all of the time at gardenweb.

Regarding the noise level of the two stage AC vs single stage ... I have a two stage heat pump. The vast majority of the time it runs in the low stage. When it is running in low, it is extremely quiet. I would guess that the Lennox two stage AC would be similarly quiet in the low stage. All of that is to say that I suspect that you should read the noise level number very carefully. Probably the best comparison in your case would be to compare the noise level of the two stage AC while it is running in low vs the noise level of the single stage AC. In that contest, I think the two stage system would win (ie be the quieter of the two). That is not to say that you necessarily need the two stage AC, just a comment on the expected noise level.

gardenweb should be able to help you a lot.

Good luck!
mikep
Posts: 3723
Joined: Wed Apr 22, 2009 9:27 pm

Re: Central AC replacement decision

Post by mikep »

Replace it in the spring/fall/winter, you will get a lot more than the 10% off of peak pricing now. Especially if it is working fine.
Sidney
Posts: 6750
Joined: Thu Mar 08, 2007 6:06 pm

Re: Central AC replacement decision

Post by Sidney »

mikep wrote:Replace it in the spring/fall/winter, you will get a lot more than the 10% off of peak pricing now. Especially if it is working fine.
In winter, at least in my area, AC contractors are also heating contractors.
I always wanted to be a procrastinator.
User avatar
NateH
Posts: 524
Joined: Tue Feb 27, 2007 9:51 am
Location: Minnesota

Re: Central AC replacement decision

Post by NateH »

Our home has a zone HVAC set-up with 2 AC units & 2 furnaces. The home was built in 1991. We replaced the failing main floor AC unit (which does the bulk of the cooling) a few years ago, but chose to let ride with the smaller unit that cools only the 2nd floor zone. It has far less hours on it and we figured "if it ain't broke..." It is still going 2 summers later. If it decides to crash in a heat wave, we can let the air circulate from the main floor.

if you already use your AC sparingly in upstate NY, have it maintained, and it "works just fine", i would leave it alone.
4X top-twenty S&P 500 prognosticator. I'd start a newsletter, but it would only have one issue per year.
User avatar
FelixTheCat
Posts: 1876
Joined: Sat Sep 24, 2011 12:39 am

Re: Central AC replacement decision

Post by FelixTheCat »

It wasn't my AC that got my house cooler. I had the AC recommended for my house. It was mediocre.

When my AC broke, my furnace need replacement too. I asked the AC guy if my current AC was under powered and he mentioned it was the correct size for my house. Then we started talking about furnaces. I spent around 7K to get the top of the line furnace that constantly circulates air in my house. The furnace is like a jet engine when I first turn on the AC until it reaches the desired temperature. Next the recirculate option kicks in to always move the air around the house. My AC rarely kicks on and my house is always cool when I set and forget the air conditioning.
Felix is a wonderful, wonderful cat.
User avatar
Epsilon Delta
Posts: 8090
Joined: Thu Apr 28, 2011 7:00 pm

Re: Central AC replacement decision

Post by Epsilon Delta »

[quote="Valuethinker"]
I am of the school that for mission critical equipment (my family lives on Lake Ontario, AC in summer is mission critical) like AC, Cars etc. you don't wait until they go wrong to replace.

Is there another Lake Ontario somewhere down in the cotton belt? Or are you from a family of snowmen and melt when it gets above freezing? :shock:
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

Stickman731, thanks for the information about the state energy incentives. New York does indeed seem to have a program somewhat similar to the Cool Energy program you described for NJ. For starters, I think I should take advantage of their subsidy for a home energy audit and get my whole house assessed for ways I can reduce energy losses in general before I buy a new central AC or any additional HVAC equipment. Most of our house is over 75 years old and could probably do with some insulation in the attic or walls or insulated curtains or insulated shades (especially for the skylights) that would help with both winter and summer efficiency. (I have five large skylights that let the sun pour in all day long. I like the sun coming in overhead and waking me up in the morning, but there's no point in having it stream in all day heating up the house when I am not even there. There are some shades in there but they are too tricky for me to operate because the skylights are so high up in the cathedral ceiling. My husband was tall and pretty adept with using a long pole but I never managed to get the hang of it.) Perhaps if I do some strategic relatively low cost things, like insulation, I may not need quite such a powerful air conditioner as was recommended yesterday on the basis on my existing setup. (Indeed I understand that getting a overpowered air condition is really bad because it will reduce the temperature before it has gotten rid of all the moisture.)

wageoghe, thanks for the link to the gardenweb forum site. That looks massively helpful! Also, I totally agree with your point that it is important to make sure that my furnace and central AC work well together, since the AC coils will be integrated into a system where it gets stacked on top of the heater and blower and the whole stack feeds into the duct system. That is why my HVAC service recommended the Lennox Signature AC line, because it is designed to go hand in glove with the Lennox Signature gas furnace I already have in place (installed a few years ago.) Fortunately I have all the paperwork on my furnace so I will definitely have that for reference when I post looking for guidance on the gardenweb site. Also, thanks so much for your explanation about the two stage noise levels--that makes a lot of sense.

mikep, I think you are right that I will probably get better deals on AC equipment when it is not AC season, though as Sidney points out, HVAC companies are very busy with heating systems during heating season (which lasts from October to April.) Everyone in these parts has a furnace, but lots of folks don't bother with central AC.
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

NateH, great idea to consider a two-zone setup. I have a very big house and most of the time, much of it is unused or underused. I might even think about getting some kind of whole house exhaust fan in one of the upstairs windows. Or just get someone to explain to me the theory of how to operate the ceiling fans in various places in our house. (I understand there is some optimal direction to have them go but I am confused about that.) I'd love to have the windows open more and let all the beautiful sounds from the natural setting in our backyard in.
likegarden
Posts: 3024
Joined: Mon Feb 26, 2007 5:33 pm

Re: Central AC replacement decision

Post by likegarden »

We also live in upstate NY, just north of Albany. Our temperatures outside went up the 10-20 years, but last winter was a long one which killed bushes which grew here for 20 years.
We had air conditioners in windows, but they felt too heavy to move in and out of windows as we grew older, and the ACs damaged the windows which got replaced. We got a new Lenox central AC installed 2 years ago by a very experienced area AC and heating company. We are satisfied with AC performance. This is a system independent of the heating system. Heating is via hot water baseboard and a furnace. The AC compressor is outside, heat exchanger and most duct work is in the attic. Since we have a 2 story house we had 3 cool air ducts going inside closets of the second floor to the first floor. Due to this extra duct work, the price was around $12,000. We love to have a constantly cool and dry house at 73 F over summer.
Call_Me_Op
Posts: 7984
Joined: Mon Sep 07, 2009 2:57 pm
Location: Milky Way

Re: Diminishing returns

Post by Call_Me_Op »

sscritic wrote:
Call_Me_Op wrote: Sounds like you might need your own central AC system. :)
I have one, it's just that I am (pick one): too cheap to run it, too much of a boglehead to run it, or both (is there a difference?).

Not really. :wink:
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein
User avatar
yatesd
Posts: 605
Joined: Sun Nov 03, 2013 8:19 am
Location: MD

Re: Central AC replacement decision

Post by yatesd »

I would try to stick with 16-17 seem. We are building a new house in MD and went with a 16 Seer Rheem 2-stage Heat Pump with a variable air handler. It is my impression that the top-tier "state of the art" options (i.e. 19-21 Seer) go for too much of a premium.

Too bad, you can't get a 2-stage with that Seer Rating. Hopefully, you have a variable speed air handler.
jebmke
Posts: 11436
Joined: Thu Apr 05, 2007 2:44 pm
Location: Delmarva Peninsula

Re: Central AC replacement decision

Post by jebmke »

yatesd wrote:Too bad, you can't get a 2-stage with that Seer Rating. Hopefully, you have a variable speed air handler.
You probably can get the lower SEER rating in a 2-stage unit. When we looked, Bryant had a range of systems. I don't recall seeing any systems without variable speed blowers.
When you discover that you are riding a dead horse, the best strategy is to dismount.
Valuethinker
Posts: 41163
Joined: Fri May 11, 2007 11:07 am

Re: Central AC replacement decision

Post by Valuethinker »

Epsilon Delta wrote:
Valuethinker wrote: I am of the school that for mission critical equipment (my family lives on Lake Ontario, AC in summer is mission critical) like AC, Cars etc. you don't wait until they go wrong to replace.

Is there another Lake Ontario somewhere down in the cotton belt? Or are you from a family of snowmen and melt when it gets above freezing? :shock:
You've been in Toronto in a heat wave then?

It's also bad much further north, within 25 miles of Georgian Bay. The summer is short, but it can be really heavy.
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

likegarden wrote:We also live in upstate NY, just north of Albany. Our temperatures outside went up the 10-20 years, but last winter was a long one which killed bushes which grew here for 20 years.
We had air conditioners in windows, but they felt too heavy to move in and out of windows as we grew older, and the ACs damaged the windows which got replaced. We got a new Lenox central AC installed 2 years ago by a very experienced area AC and heating company. We are satisfied with AC performance. This is a system independent of the heating system. Heating is via hot water baseboard and a furnace. The AC compressor is outside, heat exchanger and most duct work is in the attic. Since we have a 2 story house we had 3 cool air ducts going inside closets of the second floor to the first floor. Due to this extra duct work, the price was around $12,000. We love to have a constantly cool and dry house at 73 F over summer.
Glad to hear you are happy with your Lennox and with the job done by your HVAC contractor, which I imagine might be the same contractor we have been using for almost 25 years and have been generally happy with and will most likely use when I eventually decide what to install. Also that your observations confirm my perceptions that summer temps have been rising in the region in recent decades, so I am not just imagining things!
Beck49
Posts: 157
Joined: Sun Nov 24, 2013 8:15 pm

Re: Central AC replacement decision

Post by Beck49 »

dodecahedron wrote: I might even think about getting some kind of whole house exhaust fan in one of the upstairs windows.
+1 on the whole house fan. I grew up with one in a house in the Midwest, where it is warmer than upstate NY. I now live in western NY and routinely take advantage of this method with just a big window fan. It's amazing how many people are stunned when they find that you point the fan out rather than into the house. Good luck with your decision.
denovo
Posts: 4533
Joined: Sun Oct 13, 2013 1:04 pm

Re: Central AC replacement decision

Post by denovo »

When its hot out, I turn on the heater. Fight fire with fire.
"Don't trust everything you read on the Internet"- Abraham Lincoln
User avatar
4nursebee
Posts: 1569
Joined: Sun Apr 01, 2012 7:56 am
Location: US

Re: Central AC replacement decision

Post by 4nursebee »

OP, what is the payback for Lennox vs Goodman?
Pale Blue Dot
User avatar
Topic Author
dodecahedron
Posts: 5355
Joined: Tue Nov 12, 2013 12:28 pm

Re: Central AC replacement decision

Post by dodecahedron »

4nursebee wrote:OP, what is the payback for Lennox vs Goodman?
I never heard of a Goodman until you mentioned it. Because of my interest in a system that is compatible with/plays well with my Lennox furnace (installed just a few years ago) and the fact that Lennox is currently the only brand of AC installed by the HVAC service company we have used for decades, I wasn't really seriously considering anything else.

I did look up Goodman in Consumer Reports after you brought it up, and discovered that their systems are noteworthy for unreliability and higher than usual need for repairs.
Post Reply