Experience with heat pumps with high velocity air?

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exodusNH
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Experience with heat pumps with high velocity air?

Post by exodusNH »

I have a home that was built in 1925, in southern New Hampshire. The previous homeowners installed central AC using the small diameter / high velocity vents. The air handler is by SpacePak. The condenser unit, which failed last year, is a generic 1.5 ton, single stage and used R-22.

While the system is about 20 years old, I didn't use it for about 15 years. The air handler has a lot less age on it than it would seem. The condenser has obviously seen 20ish seasons, never covered.

I got quotes to replace it last year, before my roof failed and caused me to put it on hold. They ranged from $7000-$11000. All 3 quotes wanted to replace the air handler / coil.

My furnace also dates from 1925. It's a single pipe steam boiler, originally coal fired, but converted to oil probably in the 40s-50s. The thing will outlive us all.

In contemplating what might happen with fuel prices this winter -- I use about 200 gallons of fuel every 4-6 weeks -- I was wondering if a heat pump / AC unit might make sense?

From a technical.perspective, I believe SpacePak can handle heat distribution. Has anyone ever experienced the high-velocity heat? I'm not a huge fan of forced hot air, but I'm less of a fan of paying $2000/mo for fuel oil.

The high velocity AC is quite nice and does a great job mixing the air. No issues with the noise at all.

I have a solar installer coming in June to evaluate my house for rooftop solar. The prospect of being able to possibly, partially power my heat with solar is enticing. (I think I've got a reasonably good orientation for solar.) The oil furnace would be maintained as backup / supplemental heat. It don't think I could be fully solar, but covering half of my bill seems feasible.

Given that much of the electricity around here is from gas, I expect electric rates to go up when the utility can do so in July. (Currently just over $0.11/kwh just for the electricity. It's about the same amount for the distribution charge, so somewhere around $0.22-0.25/kwh. I use between 780-1300 kwh/mo.) I think, longer term, solar will save money. (The "competitive" electric providers are between $0.14-0.19/kwh plus the incumbent's distribution charges.)

If anyone has a trusted HVAC company, I'd appreciate DMs. I have no one I know in the field rely on.

Thank you!
talzara
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

exodusNH wrote: Fri May 20, 2022 5:25 pm I have a home that was built in 1925, in southern New Hampshire. The previous homeowners installed central AC using the small diameter / high velocity vents. The air handler is by SpacePak. ... My furnace also dates from 1925. It's a single pipe steam boiler ... I was wondering if a heat pump / AC unit might make sense? ...

Given that much of the electricity around here is from gas, I expect electric rates to go up when the utility can do so in July. (Currently just over $0.11/kwh just for the electricity. It's about the same amount for the distribution charge, so somewhere around $0.22-0.25/kwh. I use between 780-1300 kwh/mo.)
SpacePak doesn't make high-velocity heat pumps at all, only air conditioners. Its parent company makes air-to-water heat pumps, which are also sold under the SpacePak brand. However, you have steam heating, so you can't can't use an ATW heat pump.

Are you thinking about keeping your SpacePak air handler and installing another manufacturer's heat pump and coil?

What's the efficiency of your boiler? (A "furnace" is forced air.) The combustion analysis will give an efficiency percentage. A 97-year-old boiler could be very inefficient.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

talzara wrote: Mon Jun 06, 2022 3:07 pm
exodusNH wrote: Fri May 20, 2022 5:25 pm I have a home that was built in 1925, in southern New Hampshire. The previous homeowners installed central AC using the small diameter / high velocity vents. The air handler is by SpacePak. ... My furnace also dates from 1925. It's a single pipe steam boiler ... I was wondering if a heat pump / AC unit might make sense? ...

Given that much of the electricity around here is from gas, I expect electric rates to go up when the utility can do so in July. (Currently just over $0.11/kwh just for the electricity. It's about the same amount for the distribution charge, so somewhere around $0.22-0.25/kwh. I use between 780-1300 kwh/mo.)
SpacePak doesn't make high-velocity heat pumps at all, only air conditioners. Its parent company makes air-to-water heat pumps, which are also sold under the SpacePak brand. However, you have steam heating, so you can't can't use an ATW heat pump.

Are you thinking about keeping your SpacePak air handler and installing another manufacturer's heat pump and coil?

What's the efficiency of your boiler? (A "furnace" is forced air.) The combustion analysis will give an efficiency percentage. A 97-year-old boiler could be very inefficient.
Thank you for responding!

I don't even know the options I have for a heat pump. I thought that SpacePak had an option now for air-to-water forced hot air.

I wasn't sure if the heat pump could be used to heat the refrigerant, and have the coil pull heat out of it, and push it through the high-velocity ducts.

In terms of the boiler, last time it was tested, the tech said it was 78% efficient. Someone earlier today said that was probably not likely. Something in the system might be fooling modern equipment. (A ~18 year old maintenance tag on the system showed 80%.)
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Re: Experience with heat pumps with high velocity air?

Post by Valuethinker »

exodusNH wrote: Mon Jun 06, 2022 4:13 pm

In terms of the boiler, last time it was tested, the tech said it was 78% efficient. Someone earlier today said that was probably not likely. Something in the system might be fooling modern equipment. (A ~18 year old maintenance tag on the system showed 80%.)
To be clear, I might be totally wrong on this - Talzara would have a much better feel. But I am not aware that boilers more than 50 years old had anything like the efficiency of a modern boiler.

In the UK, an oil fired boiler that old would probably be around 60% efficient, might be lower.
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Re: Experience with heat pumps with high velocity air?

Post by Valuethinker »

exodusNH wrote: Fri May 20, 2022 5:25 pm

From a technical.perspective, I believe SpacePak can handle heat distribution. Has anyone ever experienced the high-velocity heat? I'm not a huge fan of forced hot air, but I'm less of a fan of paying $2000/mo for fuel oil.
Apologies if you said you had done this. But have you had an Energy Audit? There might be some "quick wins" around insulation or leak-proofing.

Do you have good evidence about how much oil you are going to use?
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Re: Experience with heat pumps with high velocity air?

Post by Tubes »

NH is a tough sell for heat pumps in mid winter. Yet, they will be useful in the "shoulder season". I'm not familiar with heat pumps and high velocity. Heat pumps are very common where I live using standard velocity air handlers. The biggest complaint is the air feels cool, and that's very low velocity!
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Valuethinker wrote: Tue Jun 07, 2022 2:50 am
exodusNH wrote: Mon Jun 06, 2022 4:13 pm

In terms of the boiler, last time it was tested, the tech said it was 78% efficient. Someone earlier today said that was probably not likely. Something in the system might be fooling modern equipment. (A ~18 year old maintenance tag on the system showed 80%.)
To be clear, I might be totally wrong on this - Talzara would have a much better feel. But I am not aware that boilers more than 50 years old had anything like the efficiency of a modern boiler.

In the UK, an oil fired boiler that old would probably be around 60% efficient, might be lower.
I was surprised, too. When I first moved in, there was a maintenance tag on it that showed 78% or 80%. When I had it serviced, they came up with 78% or 80%. It's certainly possible the field tools they use to measure simply weren't designed to handle a system this old. The company that made the boiler was based in Boston and filed for bankruptcy somewhere around 1927. (I believe my boiler was installed in 1925 since that matches the date when the municipal water service was installed. That city department has records going back to the beginning!) Based on a prior discussion with a service tech, it was originally coal and likely converted to oil in the 40s or 50s.

I love the quality of steam heat. But I don't know whether 150-200 gallons every 4-6 weeks is a lot. The basement stays very warm in the winter, so I know a lot of heat is being dumped into uninhabited space, but the basement ceiling isn't insulated, so some of it migrates up.

The prior owners installed the SpacePak system. I can't imagine they would have done so if the place was not insulated. NH electric rates have always been high.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Valuethinker wrote: Tue Jun 07, 2022 6:04 am
exodusNH wrote: Fri May 20, 2022 5:25 pm

From a technical.perspective, I believe SpacePak can handle heat distribution. Has anyone ever experienced the high-velocity heat? I'm not a huge fan of forced hot air, but I'm less of a fan of paying $2000/mo for fuel oil.
Apologies if you said you had done this. But have you had an Energy Audit? There might be some "quick wins" around insulation or leak-proofing.

Do you have good evidence about how much oil you are going to use?

I had not. Someone else mentioned it in a separate thread I commented on. I DM'd Talzara; they kindly replied to this post.

I've emailed my oil company to get the last 12 months of usage so I can start that process.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Tubes wrote: Tue Jun 07, 2022 6:20 am NH is a tough sell for heat pumps in mid winter. Yet, they will be useful in the "shoulder season". I'm not familiar with heat pumps and high velocity. Heat pumps are very common where I live using standard velocity air handlers. The biggest complaint is the air feels cool, and that's very low velocity!
I'm in southern NH. My totally uneducated guess is that Jan and Feb might be suboptimal, but Oct - Dec and Mar - May could be good candidates with the oil beast handling the frigid winter.

My parents moved out of CT to NH in '86. Winters are more mild then when I was a kid. That's not to say we don't have nasty cold snaps -- as recently as December 2008, we had a stretch where is was in single digits for 5-6 days. (Following the bad ice storm that year. I had no power that entire time except for a gas generator my father was able to find. One of the nice things about old appliances is that they aren't electric hungry. I just needed 5 A @ 120V to run the oil pump and a bit for the spark. Steam moved it self. Standing-pilot gas water heater provided hot water uninterrupted.)

I'd have replaced it years ago, but there's a asbestos mitigation component that drives up the cost and the ROI. When I had it serviced last year, I asked the tech if a new boiler would have dramatically lower oil consumption. He didn't think it would go as far as to lower the usage by 50%. (And the basement would be cold, meaning I'd also need to insulate the ceiling down there.)
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Re: Experience with heat pumps with high velocity air?

Post by ncbill »

exodusNH wrote: Tue Jun 07, 2022 8:17 am
Valuethinker wrote: Tue Jun 07, 2022 2:50 am
exodusNH wrote: Mon Jun 06, 2022 4:13 pm

In terms of the boiler, last time it was tested, the tech said it was 78% efficient. Someone earlier today said that was probably not likely. Something in the system might be fooling modern equipment. (A ~18 year old maintenance tag on the system showed 80%.)
To be clear, I might be totally wrong on this - Talzara would have a much better feel. But I am not aware that boilers more than 50 years old had anything like the efficiency of a modern boiler.

In the UK, an oil fired boiler that old would probably be around 60% efficient, might be lower.
I was surprised, too. When I first moved in, there was a maintenance tag on it that showed 78% or 80%. When I had it serviced, they came up with 78% or 80%. It's certainly possible the field tools they use to measure simply weren't designed to handle a system this old. The company that made the boiler was based in Boston and filed for bankruptcy somewhere around 1927. (I believe my boiler was installed in 1925 since that matches the date when the municipal water service was installed. That city department has records going back to the beginning!) Based on a prior discussion with a service tech, it was originally coal and likely converted to oil in the 40s or 50s.

I love the quality of steam heat. But I don't know whether 150-200 gallons every 4-6 weeks is a lot. The basement stays very warm in the winter, so I know a lot of heat is being dumped into uninhabited space, but the basement ceiling isn't insulated, so some of it migrates up.

The prior owners installed the SpacePak system. I can't imagine they would have done so if the place was not insulated. NH electric rates have always been high.
We had a one-pipe steam system for heat on a home built in the early 1920s (coal converted to natural gas)

From everything I've read "one-pipe" systems are under 60% efficient...maybe that 80% rating was if feeding a circulating water system.
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Re: Experience with heat pumps with high velocity air?

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exodusNH wrote: Tue Jun 07, 2022 8:25 am
Tubes wrote: Tue Jun 07, 2022 6:20 am NH is a tough sell for heat pumps in mid winter. Yet, they will be useful in the "shoulder season". I'm not familiar with heat pumps and high velocity. Heat pumps are very common where I live using standard velocity air handlers. The biggest complaint is the air feels cool, and that's very low velocity!
I'm in southern NH. My totally uneducated guess is that Jan and Feb might be suboptimal, but Oct - Dec and Mar - May could be good candidates with the oil beast handling the frigid winter.
OP, try out some online calculators. Here's just one: https://www.remodelingcalculator.org/he ... fficiency/

So my take-away is that you want to keep the one pipe steam and use it as an adjunct to a heat pump?

That's kind of what I do, in a way. I have two HVAC systems, one for the first floor, the other for the second. The first floor is a natural gas fired forced air furnace. The second floor is a heat pump. Since hot air rises, the first floor boosts the second floor heat pump. My HP doesn't come on a whole lot.

It sounds like you want to do it in reverse, i.e. use the old system as backup to the heat pump. In heat pump parlance, that's called "auxiliary heat". It works really wall to have natural gas furnace or resistance heat as auxiliary since they are near instant-on. The control systems of the heat pump are also connected to the auxiliary and call for it only at the right time. I'm going to guess that may not work so well with steam, since the boiler basically has to be ready and on call. You just don't fire up a steam boiler at a moment's notice. So, balancing the load factor of steam with the heat pump output will be a challenge. I'm not familiar with anyone who has tried that. It is an interesting idea, though.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Tubes wrote: Tue Jun 07, 2022 9:21 am
exodusNH wrote: Tue Jun 07, 2022 8:25 am
Tubes wrote: Tue Jun 07, 2022 6:20 am NH is a tough sell for heat pumps in mid winter. Yet, they will be useful in the "shoulder season". I'm not familiar with heat pumps and high velocity. Heat pumps are very common where I live using standard velocity air handlers. The biggest complaint is the air feels cool, and that's very low velocity!
I'm in southern NH. My totally uneducated guess is that Jan and Feb might be suboptimal, but Oct - Dec and Mar - May could be good candidates with the oil beast handling the frigid winter.
OP, try out some online calculators. Here's just one: https://www.remodelingcalculator.org/he ... fficiency/

So my take-away is that you want to keep the one pipe steam and use it as an adjunct to a heat pump?

That's kind of what I do, in a way. I have two HVAC systems, one for the first floor, the other for the second. The first floor is a natural gas fired forced air furnace. The second floor is a heat pump. Since hot air rises, the first floor boosts the second floor heat pump. My HP doesn't come on a whole lot.

It sounds like you want to do it in reverse, i.e. use the old system as backup to the heat pump. In heat pump parlance, that's called "auxiliary heat". It works really wall to have natural gas furnace or resistance heat as auxiliary since they are near instant-on. The control systems of the heat pump are also connected to the auxiliary and call for it only at the right time. I'm going to guess that may not work so well with steam, since the boiler basically has to be ready and on call. You just don't fire up a steam boiler at a moment's notice. So, balancing the load factor of steam with the heat pump output will be a challenge. I'm not familiar with anyone who has tried that. It is an interesting idea, though.
The challenge is that it's not feasible to redo the radiators in a more modern configuration without a major remodel, at least for the upstairs radiators.

A full forced hot air furnace doesn't seem likely either given the challenges of getting the duct work up to the attic to be distributed via the air handler. (Though I suppose if one were to demo the chimney, which is only used by that boiler, you'd have the room to run up to the attic...)

My boiler is what the industry calls "snowmen". You can find pictures by searching for that, though mine is in exceptional shape.

I figure that an air-sourced heat pump has limits in NH and the boiler would need to be used for auxiliary heat. I'd even be OK with having to manually configure it. I probably have room for a ground-sourced heat pump, though getting the coolant to the building would be a bit of fun.

I guess my real problem is that I don't have a trusted HVAC "guy". None of my friends have an old house like this -- they're all essentially plug-and-play gas furnaces.

What I really need is This Old House to come out and help. As a kid, I lived in a rural part of NH and could only get TV over rabbit ears. WGBH was one of the few channels we could get. As a kid, I watched that show all of the time. It would be a real kick to meet with them, even without Bob and Norm.
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Re: Experience with heat pumps with high velocity air?

Post by ekid »

Real engineers in the home heat industry are rare. And we need 'em.

Sadly, the sales guys are not knowlegeable about thermodynamics; they only know their own product. (maybe)

But when I abandoned my own perfectly good oil furnace (eff~60-65%) for 90-95%+ bottlegas condensing furnace...I don't even need to check the tank, much less think about cost of heating.

No kidding, I went two full years on one fill.
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Re: Experience with heat pumps with high velocity air?

Post by Tubes »

Geez, oh man, OP, I feel for you. As the previous poster says, "real engineers" are hard to find in this field, especially residential.

Basically, you get salespeople who just want to sell you the latest and greatest: "Our air handler can be fitted with the latest COVID-19 capable virus catching filter. " Blah, blah, blah.

You have an interesting situation that I think makes a lot of sense and is solve-able, but you need a real HVAC person to help:

1) Using perfectly functional steam heat as an auxiliary back up to a heat pump.

2) Installing a high velocity heat pump in place of the existing high velocity system.

This is not rocket science, but both #1 and #2 go against the typical situation of a high pressure salesperson, so they will give you gibberish.

I wish I could be of more help. I can't from a distance, but I really wish you good luck in finding the right person to help.
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Re: Experience with heat pumps with high velocity air?

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150 gallons of heating oil is 20 million Btu's. So over the course of 6 weeks, you're using 20,000 Btu's per hour average. That's kind of a lot, but not ridiculously so. Let's just say for fun that it costs $600. I don't know.

Heat pumps of course are less efficient when it's really cold, like it gets in new hampshire. But just for fun, let's say you have a COP of 3 and then you'd need 2000 kW-h in the same time frame (3412 BTu's is 1 kW-h). So if you're paying 22 cents, that's going to be 440 dollars vs. the 600 above.

I am not terribly sure if a COP of 3 is realistic in your weather. I'm also not sure if you can get a heat pump with high-velocity ducts.
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Re: Experience with heat pumps with high velocity air?

Post by NYLD »

I don’t have any direct knowledge to add here but there is a Facebook group ‘electrify everything’ that could be a good resource to discover what is possible in your situation and to potentially point you toward what they call HVAC 2.0 contractors who are more experienced in the heat pump space.
Last edited by NYLD on Tue Jun 07, 2022 4:01 pm, edited 1 time in total.
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

exodusNH wrote: Mon Jun 06, 2022 4:13 pm I don't even know the options I have for a heat pump. I thought that SpacePak had an option now for air-to-water forced hot air.
Yes, that's the air-to-water heat pump that I mentioned. You can use it with a hydronic coil, but you can't use your existing air handler. The coil comes with its own high-velocity air handler. For example:
It's going to be expensive. The SpacePak Solstice has a Japanese compressor and a Japanese inverter, but it costs much more than a real Japanese air-to-water heat pump. The Asian HVAC manufacturers don't sell their air-to-water heat pumps in the United States. They sell millions of them in Asia and Europe, but not here.
exodusNH wrote: Mon Jun 06, 2022 4:13 pm I wasn't sure if the heat pump could be used to heat the refrigerant, and have the coil pull heat out of it, and push it through the high-velocity ducts.
That's not air-to-water. That's air-to-air, like a conventional ducted heat pumps. The problem is that you have a high-velocity system, which limits your choices.

SpacePak only makes high-velocity air conditioners, not heat pumps. You may be able to use a heat pump from another manufacturer. Unico has approved the Bosch IDS heat pump for use with its high-velocity system. You have SpacePak, so it would not be approved, but it should work. However, the Bosch IDS is not a low-temperature heat pump. It loses a lot of capacity at low temperatures: viewtopic.php?p=6559945#p6559945
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

exodusNH wrote: Tue Jun 07, 2022 8:17 am I was surprised, too. When I first moved in, there was a maintenance tag on it that showed 78% or 80%. When I had it serviced, they came up with 78% or 80%. It's certainly possible the field tools they use to measure simply weren't designed to handle a system this old. ...

I love the quality of steam heat. But I don't know whether 150-200 gallons every 4-6 weeks is a lot. The basement stays very warm in the winter, so I know a lot of heat is being dumped into uninhabited space, but the basement ceiling isn't insulated, so some of it migrates up.
Combustion analyzers use the temperature and O₂ content of the exhaust to calculate the efficiency. They assume that the heat is either in the steam or the exhaust. Since your boiler is losing heat to the basement, that heat is not in the exhaust, so it assumes that the heat has gone into the steam.

That's why it's reporting a combustion efficiency of 78%. Your actual efficiency is lower.

Your basement ceiling isn't insulated, but your foundation probably isn't insulated either. The heat is still being lost to the ground, which is losing heat to the air.
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

exodusNH wrote: Tue Jun 07, 2022 9:41 am I guess my real problem is that I don't have a trusted HVAC "guy". None of my friends have an old house like this -- they're all essentially plug-and-play gas furnaces.

What I really need is This Old House to come out and help. As a kid, I lived in a rural part of NH and could only get TV over rabbit ears. WGBH was one of the few channels we could get. As a kid, I watched that show all of the time. It would be a real kick to meet with them, even without Bob and Norm.
The problem is that both of your HVAC systems are uncommon. Steam is much less common than hot water, and high-velocity is much less common than conventional forced air. It limits your choices. You can't use an air-to-water heat pump with steam, and there's no approved heat pump for your high-velocity system. You can use air-to-water with a hydronic coil, or you can use an unapproved heat pump.

This Old House installs a lot of mini-splits. For the cost of a SpacePak air-to-water heat pump and a hydronic air handler, you could install two or maybe three mini-splits.

You don't have to hang mini-split heads on every wall. For the first floor, put the slim duct heads between the floor joists in the basement, and run them to floor registers. For the second floor, hide a slim duct head in the ceiling joists or a closet.

Since you're keeping your steam and high-velocity systems, the mini-splits don't have to supply every room in the house. Run the steam system to heat the other rooms, run the high-velocity air handler to distribute air through the house.
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

firebirdparts wrote: Tue Jun 07, 2022 3:40 pm 150 gallons of heating oil is 20 million Btu's. So over the course of 6 weeks, you're using 20,000 Btu's per hour average. That's kind of a lot, but not ridiculously so. Let's just say for fun that it costs $600. I don't know.

Heat pumps of course are less efficient when it's really cold, like it gets in new hampshire. But just for fun, let's say you have a COP of 3 and then you'd need 2000 kW-h in the same time frame (3412 BTu's is 1 kW-h). So if you're paying 22 cents, that's going to be 440 dollars vs. the 600 above.
You forgot to take into account combustion efficiency. The 78% measured efficiency is overstated because it's including heat lost to the basement. If the boiler is 65% efficient and the heat pump has a seasonal average COP of 2.5, that's only 1,600 kWh.

Home heating oil costs $5.50 per gallon in New Hampshire, and it could be even higher next winter. There's a global shortage of diesel right now.

That makes it $825 for oil and $352 for the heat pump.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

talzara wrote: Tue Jun 07, 2022 7:02 pm
exodusNH wrote: Tue Jun 07, 2022 9:41 am I guess my real problem is that I don't have a trusted HVAC "guy". None of my friends have an old house like this -- they're all essentially plug-and-play gas furnaces.

What I really need is This Old House to come out and help. As a kid, I lived in a rural part of NH and could only get TV over rabbit ears. WGBH was one of the few channels we could get. As a kid, I watched that show all of the time. It would be a real kick to meet with them, even without Bob and Norm.
The problem is that both of your HVAC systems are uncommon. Steam is much less common than hot water, and high-velocity is much less common than conventional forced air. It limits your choices. You can't use an air-to-water heat pump with steam, and there's no approved heat pump for your high-velocity system. You can use air-to-water with a hydronic coil, or you can use an unapproved heat pump.

This Old House installs a lot of mini-splits. For the cost of a SpacePak air-to-water heat pump and a hydronic air handler, you could install two or maybe three mini-splits.

You don't have to hang mini-split heads on every wall. For the first floor, put the slim duct heads between the floor joists in the basement, and run them to floor registers. For the second floor, hide a slim duct head in the ceiling joists or a closet.

Since you're keeping your steam and high-velocity systems, the mini-splits don't have to supply every room in the house. Run the steam system to heat the other rooms, run the high-velocity air handler to distribute air through the house.
Thank you for all of your replies!

Mini splits on the first floor are tough because I have very little open wall space. All of the rooms are small and have a lot of windows. They're more feasible on the second floor -- though to the lack of convenient chase space would probably mean the ugly supply and drain lines running on the side of the house. The rooms are all small, roughly 120 sq ft each.

While there is a fireplace in the living room, the size of the living room makes a pellet stove infeasible. A gas insert would be easier. The gas supply line runs under the fireplace.

As per someone's suggestion, I have applied for an energy audit. My oil company send me over my history for the last 16 months. Between March of 2021, when I got my last delivery of the season and April 2022, I used about 950 gallons of oil.

I'm not married to either of these systems. The air handler is ~20 years old, though it went unused for most of my 17 years. The condenser unit has failed, as it was exposed to the elements.

If I could replace the steam radiators with something that didn't require major demo, I'd consider it. The asbestos abatement of the existing boiler poses problems.

In NH, I believe it is legal for a home owner to remove it yourself, but I'm not sure I'm up for that task.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

ekid wrote: Tue Jun 07, 2022 12:35 pm Real engineers in the home heat industry are rare. And we need 'em.

Sadly, the sales guys are not knowlegeable about thermodynamics; they only know their own product. (maybe)

But when I abandoned my own perfectly good oil furnace (eff~60-65%) for 90-95%+ bottlegas condensing furnace...I don't even need to check the tank, much less think about cost of heating.

No kidding, I went two full years on one fill.
That's an interesting point. I guess I'm hung up on the unknown of asbestos abatement and whether the modern boilers work well with single pipe steam.

My $ idea is to start an asbestos abatement company that employs fit 60+ year olds and undercut everyone's pricing. Given how long it takes for asbestos-related health concerns to show up, especially with proper protection, it seems like it could be a game changer! ;)
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Tubes wrote: Tue Jun 07, 2022 2:56 pm Geez, oh man, OP, I feel for you. As the previous poster says, "real engineers" are hard to find in this field, especially residential.

Basically, you get salespeople who just want to sell you the latest and greatest: "Our air handler can be fitted with the latest COVID-19 capable virus catching filter. " Blah, blah, blah.

You have an interesting situation that I think makes a lot of sense and is solve-able, but you need a real HVAC person to help:

1) Using perfectly functional steam heat as an auxiliary back up to a heat pump.

2) Installing a high velocity heat pump in place of the existing high velocity system.

This is not rocket science, but both #1 and #2 go against the typical situation of a high pressure salesperson, so they will give you gibberish.

I wish I could be of more help. I can't from a distance, but I really wish you good luck in finding the right person to help.
I'm about 45 minutes north of Boston if anyone knows anyone!
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

talzara wrote: Tue Jun 07, 2022 7:25 pm
firebirdparts wrote: Tue Jun 07, 2022 3:40 pm 150 gallons of heating oil is 20 million Btu's. So over the course of 6 weeks, you're using 20,000 Btu's per hour average. That's kind of a lot, but not ridiculously so. Let's just say for fun that it costs $600. I don't know.

Heat pumps of course are less efficient when it's really cold, like it gets in new hampshire. But just for fun, let's say you have a COP of 3 and then you'd need 2000 kW-h in the same time frame (3412 BTu's is 1 kW-h). So if you're paying 22 cents, that's going to be 440 dollars vs. the 600 above.
You forgot to take into account combustion efficiency. The 78% measured efficiency is overstated because it's including heat lost to the basement. If the boiler is 65% efficient and the heat pump has a seasonal average COP of 2.5, that's only 1,600 kWh.

Home heating oil costs $5.50 per gallon in New Hampshire, and it could be even higher next winter. There's a global shortage of diesel right now.

That makes it $825 for oil and $352 for the heat pump.
Yep, it went from $2.99/gal in March 2021 to $5.06 on April 5, when I got my last delivery. I shouldn't get another delivery until November 2022.

I think $6-$10/gallon, while a wide range, is not out of the question. It almost always tracks slightly more than diesel, especially when you consider there's no road tax in the pricing.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

talzara wrote: Tue Jun 07, 2022 6:34 pm
exodusNH wrote: Mon Jun 06, 2022 4:13 pm I don't even know the options I have for a heat pump. I thought that SpacePak had an option now for air-to-water forced hot air.
Yes, that's the air-to-water heat pump that I mentioned. You can use it with a hydronic coil, but you can't use your existing air handler. The coil comes with its own high-velocity air handler. For example:
It's going to be expensive. The SpacePak Solstice has a Japanese compressor and a Japanese inverter, but it costs much more than a real Japanese air-to-water heat pump. The Asian HVAC manufacturers don't sell their air-to-water heat pumps in the United States. They sell millions of them in Asia and Europe, but not here.
exodusNH wrote: Mon Jun 06, 2022 4:13 pm I wasn't sure if the heat pump could be used to heat the refrigerant, and have the coil pull heat out of it, and push it through the high-velocity ducts.
That's not air-to-water. That's air-to-air, like a conventional ducted heat pumps. The problem is that you have a high-velocity system, which limits your choices.

SpacePak only makes high-velocity air conditioners, not heat pumps. You may be able to use a heat pump from another manufacturer. Unico has approved the Bosch IDS heat pump for use with its high-velocity system. You have SpacePak, so it would not be approved, but it should work. However, the Bosch IDS is not a low-temperature heat pump. It loses a lot of capacity at low temperatures: viewtopic.php?p=6559945#p6559945
I had gotten quotes, last spring, for $7,000-$10,000 to replace the condenser unit and air handler with new SpacePak equipment. The system is about 20 years old, though I didn't use it for the majority of my 17 years here. (My SO has asthma, so needs AC in the summer. Prior to 2017, I was content to keep windows open and use a fan.)

When you say expensive, what are we talking? $20,000? $30,000? If I'm looking at $6k alone for oil next year and already need a new AC unit, I wonder if something like that makes sense.

Though your note on a separate reply made some interesting points with the mini splits and small heads.

Do you have any contacts or contacts-of-contacts I can reach out to? (Feel free to DM.) As I said, I'm in southern NH, about 45 (traffic free) minutes north of Boston.

I really appreciate all the time you've taken to reply! Just having this little bit of knowledge is helpful.
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Re: Experience with heat pumps with high velocity air?

Post by Valuethinker »

exodusNH wrote: Tue Jun 07, 2022 11:40 pm

In NH, I believe it is legal for a home owner to remove it yourself, but I'm not sure I'm up for that task.
I believe that all the paranoia and safety around asbestos removal is justified.

You mention your partner has asthma. So, doubly so.

You would have to use a contractor to do that. Who would seal it off, wear proper protection etc. If it's anything like north of the border, they will provide a certificate of rectification -- and you'll need that when you or your estate sells the house.

I don't know if a high velocity HP system would work for you. Your system sounds exactly like my mother's (north of the border) except they moved from oil to electric induction about 25 years ago (this is horribly inefficient, however electricity prices were artificially low & my mother has never trusted gas). House built in 1920s. Retrofitted air through small HV ducts.

It's worth having a post on some green building forums to see if anyone has any helpful thoughts. Although I think Talzara has pretty much laid out the landscape.

In any case, steam will serve as an adequate back up for cold weather.

I am afraid I don't see any relief in oil prices before mid 2023. Places like Germany use a lot of oil for heating, and if natural gas is going to be in short supply due to the war/ geopolitics ...
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Valuethinker wrote: Wed Jun 08, 2022 2:56 am
exodusNH wrote: Tue Jun 07, 2022 11:40 pm

In NH, I believe it is legal for a home owner to remove it yourself, but I'm not sure I'm up for that task.
I believe that all the paranoia and safety around asbestos removal is justified.

You mention your partner has asthma. So, doubly so.

You would have to use a contractor to do that. Who would seal it off, wear proper protection etc. If it's anything like north of the border, they will provide a certificate of rectification -- and you'll need that when you or your estate sells the house.

I don't know if a high velocity HP system would work for you. Your system sounds exactly like my mother's (north of the border) except they moved from oil to electric induction about 25 years ago (this is horribly inefficient, however electricity prices were artificially low & my mother has never trusted gas). House built in 1920s. Retrofitted air through small HV ducts.

It's worth having a post on some green building forums to see if anyone has any helpful thoughts. Although I think Talzara has pretty much laid out the landscape.

In any case, steam will serve as an adequate back up for cold weather.

I am afraid I don't see any relief in oil prices before mid 2023. Places like Germany use a lot of oil for heating, and if natural gas is going to be in short supply due to the war/ geopolitics ...
New England in general has a gas supply problem due to lack of pipeline capacity. We use a lot for electricity generation, since so many people have fought against nuclear, solar, and wind. NH in general is (or was when I last looked) a net energy exporter. In the big 2003 cascading power failure, NH islanded itself. There were no major outages here. But even with that, the current all-in kwh cost is something like $0.22/kwh. The rate was last set in Feb and will reset as the end of July. I haven't seen projections yet on the new rates, but CT has already approved a 5% increase, making the July 2022 - Dec 2022 rate 72% higher than the same period last year.

Our "competitive" supplier market has collapsed. The few that are available are all substantially higher than the incumbent, Eversource.
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Re: Experience with heat pumps with high velocity air?

Post by Valuethinker »

exodusNH wrote: Wed Jun 08, 2022 6:49 am

New England in general has a gas supply problem due to lack of pipeline capacity. We use a lot for electricity generation, since so many people have fought against nuclear, solar, and wind. NH in general is (or was when I last looked) a net energy exporter. In the big 2003 cascading power failure, NH islanded itself. There were no major outages here. But even with that, the current all-in kwh cost is something like $0.22/kwh. The rate was last set in Feb and will reset as the end of July. I haven't seen projections yet on the new rates, but CT has already approved a 5% increase, making the July 2022 - Dec 2022 rate 72% higher than the same period last year.

Our "competitive" supplier market has collapsed. The few that are available are all substantially higher than the incumbent, Eversource.

I understand there has also been opposition to new transmission lines from Hydro Quebec (Maine, VT, NYS), as well.

My main thought was that as Europe may not have enough natural gas next winter, places like Germany will burn more oil.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

Valuethinker wrote: Wed Jun 08, 2022 7:29 am
exodusNH wrote: Wed Jun 08, 2022 6:49 am

New England in general has a gas supply problem due to lack of pipeline capacity. We use a lot for electricity generation, since so many people have fought against nuclear, solar, and wind. NH in general is (or was when I last looked) a net energy exporter. In the big 2003 cascading power failure, NH islanded itself. There were no major outages here. But even with that, the current all-in kwh cost is something like $0.22/kwh. The rate was last set in Feb and will reset as the end of July. I haven't seen projections yet on the new rates, but CT has already approved a 5% increase, making the July 2022 - Dec 2022 rate 72% higher than the same period last year.

Our "competitive" supplier market has collapsed. The few that are available are all substantially higher than the incumbent, Eversource.

I understand there has also been opposition to new transmission lines from Hydro Quebec (Maine, VT, NYS), as well.

My main thought was that as Europe may not have enough natural gas next winter, places like Germany will burn more oil.
Yep. Short-sited local opposition that always wants to throw us back to the stone age even though it was hydro.

Not only will Germany look to more oil, but the supply gas supply will be even more tight since we're sending it over to Europe to help backfill. Of course, that uses up both supply AND liquification capacity.
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

exodusNH wrote: Tue Jun 07, 2022 11:40 pm Mini splits on the first floor are tough because I have very little open wall space. All of the rooms are small and have a lot of windows. They're more feasible on the second floor -- though to the lack of convenient chase space would probably mean the ugly supply and drain lines running on the side of the house. The rooms are all small, roughly 120 sq ft each.
That's why I suggested using floor registers and hiding the slim duct heads in the basement. One head can supply three rooms. HVAC contractors price by the number of heads, and ducts cost a lot less than heads.
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Re: Experience with heat pumps with high velocity air?

Post by ncbill »

exodusNH wrote: Tue Jun 07, 2022 11:40 pm
talzara wrote: Tue Jun 07, 2022 7:02 pm
exodusNH wrote: Tue Jun 07, 2022 9:41 am I guess my real problem is that I don't have a trusted HVAC "guy". None of my friends have an old house like this -- they're all essentially plug-and-play gas furnaces.

What I really need is This Old House to come out and help. As a kid, I lived in a rural part of NH and could only get TV over rabbit ears. WGBH was one of the few channels we could get. As a kid, I watched that show all of the time. It would be a real kick to meet with them, even without Bob and Norm.
The problem is that both of your HVAC systems are uncommon. Steam is much less common than hot water, and high-velocity is much less common than conventional forced air. It limits your choices. You can't use an air-to-water heat pump with steam, and there's no approved heat pump for your high-velocity system. You can use air-to-water with a hydronic coil, or you can use an unapproved heat pump.

This Old House installs a lot of mini-splits. For the cost of a SpacePak air-to-water heat pump and a hydronic air handler, you could install two or maybe three mini-splits.

You don't have to hang mini-split heads on every wall. For the first floor, put the slim duct heads between the floor joists in the basement, and run them to floor registers. For the second floor, hide a slim duct head in the ceiling joists or a closet.

Since you're keeping your steam and high-velocity systems, the mini-splits don't have to supply every room in the house. Run the steam system to heat the other rooms, run the high-velocity air handler to distribute air through the house.
Thank you for all of your replies!

Mini splits on the first floor are tough because I have very little open wall space. All of the rooms are small and have a lot of windows. They're more feasible on the second floor -- though to the lack of convenient chase space would probably mean the ugly supply and drain lines running on the side of the house. The rooms are all small, roughly 120 sq ft each...
There are mini-splits that don't use the traditional, large, "cassette" on the interior wall.

Some offer overhead vents like you'd see with a traditional split system that was using ductwork.

I assume the rest of the "cassette" interior unit is on the outside wall feeding that overhead vent via mini-duct, as with a package unit.
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Re: Experience with heat pumps with high velocity air?

Post by talzara »

exodusNH wrote: Wed Jun 08, 2022 12:01 am When you say expensive, what are we talking? $20,000? $30,000? If I'm looking at $6k alone for oil next year and already need a new AC unit, I wonder if something like that makes sense.
Yes, I would expect an air-to-water heat pump high-velocity system to cost $20,000 or more.

How about buying a Unico high-velocity air handler and connecting it to an Asian low-temperature mini-split outdoor unit? For $20,000, you might even be able to buy two systems, one for each floor. Unico is much more flexible than SpacePak because it doesn't make its own outside units.
exodusNH wrote: Wed Jun 08, 2022 12:01 am Do you have any contacts or contacts-of-contacts I can reach out to? (Feel free to DM.) As I said, I'm in southern NH, about 45 (traffic free) minutes north of Boston.
Start with the Unico Local Expert for New Hampshire: https://www.unicosystem.com/your-local-expert/

It's actually RST Thermal in Massachusetts, which is owned by the plumber on This Old House. You're too far from Boston, but they'll refer you to a contractor who's closer.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

talzara wrote: Wed Jun 08, 2022 2:36 pm
exodusNH wrote: Wed Jun 08, 2022 12:01 am When you say expensive, what are we talking? $20,000? $30,000? If I'm looking at $6k alone for oil next year and already need a new AC unit, I wonder if something like that makes sense.
Yes, I would expect an air-to-water heat pump high-velocity system to cost $20,000 or more.

How about buying a Unico high-velocity air handler and connecting it to an Asian low-temperature mini-split outdoor unit? For $20,000, you might even be able to buy two systems, one for each floor. Unico is much more flexible than SpacePak because it doesn't make its own outside units.
exodusNH wrote: Wed Jun 08, 2022 12:01 am Do you have any contacts or contacts-of-contacts I can reach out to? (Feel free to DM.) As I said, I'm in southern NH, about 45 (traffic free) minutes north of Boston.
Start with the Unico Local Expert for New Hampshire: https://www.unicosystem.com/your-local-expert/

It's actually RST Thermal in Massachusetts, which is owned by the plumber on This Old House. High-velocity systems are uncommon. It's a small world.
Talzara, I can't thank you enough for all of the time you spent replying! Trying to navigate this with Google searches always wind up leading to dead ends, given the unusual situation I have.

I rather like my house -- old maple hardwood flooring throughout, but stuff like this is very frustrating to manage.
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Re: Experience with heat pumps with high velocity air?

Post by kevinf »

exodusNH wrote: Tue Jun 07, 2022 11:46 pm
Tubes wrote: Tue Jun 07, 2022 2:56 pm Geez, oh man, OP, I feel for you. As the previous poster says, "real engineers" are hard to find in this field, especially residential.

Basically, you get salespeople who just want to sell you the latest and greatest: "Our air handler can be fitted with the latest COVID-19 capable virus catching filter. " Blah, blah, blah.

You have an interesting situation that I think makes a lot of sense and is solve-able, but you need a real HVAC person to help:

1) Using perfectly functional steam heat as an auxiliary back up to a heat pump.

2) Installing a high velocity heat pump in place of the existing high velocity system.

This is not rocket science, but both #1 and #2 go against the typical situation of a high pressure salesperson, so they will give you gibberish.

I wish I could be of more help. I can't from a distance, but I really wish you good luck in finding the right person to help.
I'm about 45 minutes north of Boston if anyone knows anyone!
Ask on the heatinghelp.com forum, there should be several steam HVAC experts near Boston that would be willing to make that drive and discuss your options.

https://forum.heatinghelp.com/discussions
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Re: Experience with heat pumps with high velocity air?

Post by iamlucky13 »

exodusNH wrote: Fri May 20, 2022 5:25 pm From a technical.perspective, I believe SpacePak can handle heat distribution. Has anyone ever experienced the high-velocity heat?
I have not experienced a high velocity heat pump, but I would expect it to exacerbate one of the complications of ducted heat pumps.

A gas, oil, or electric furnace typically produces air that is above body temperature when it exits the register. The result is an increased perception of heat while the unit is running and air is circulating around the room.

Heat pumps typically produce air slightly cooler than body temperature at the register (I think mine is usually 87 degrees, if I remember right). The result is actually a sense of cooling while the unit is running and the air circulating around the room. And heat pumps typically run a greater percentage of the time than conventional furnaces so it will be more persistent.

As a result, my observation has been that the same level of comfort from a heat pump is often achieved by turning the thermostat up by 1-2 degrees F compared to if using gas, oil, or electric heat. With a higher air velocity, it might take and extra 1-2 degrees more.

That's not a reason not to get a heat pump, in my opinion. Just something to be aware of to maintain your comfort level.

High velocity air usually also means more noise, but it shouldn't be worse than what you're already used to.
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Re: Experience with heat pumps with high velocity air?

Post by exodusNH »

iamlucky13 wrote: Wed Jun 08, 2022 4:46 pm
exodusNH wrote: Fri May 20, 2022 5:25 pm From a technical.perspective, I believe SpacePak can handle heat distribution. Has anyone ever experienced the high-velocity heat?
I have not experienced a high velocity heat pump, but I would expect it to exacerbate one of the complications of ducted heat pumps.

A gas, oil, or electric furnace typically produces air that is above body temperature when it exits the register. The result is an increased perception of heat while the unit is running and air is circulating around the room.

Heat pumps typically produce air slightly cooler than body temperature at the register (I think mine is usually 87 degrees, if I remember right). The result is actually a sense of cooling while the unit is running and the air circulating around the room. And heat pumps typically run a greater percentage of the time than conventional furnaces so it will be more persistent.

As a result, my observation has been that the same level of comfort from a heat pump is often achieved by turning the thermostat up by 1-2 degrees F compared to if using gas, oil, or electric heat. With a higher air velocity, it might take and extra 1-2 degrees more.

That's not a reason not to get a heat pump, in my opinion. Just something to be aware of to maintain your comfort level.

High velocity air usually also means more noise, but it shouldn't be worse than what you're already used to.
The current system makes a pleasant white noise while it's running. It's certainly less jarring than when the cast iron radiators flex!
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