4 ms·

As someone who lives in the northeast and has a 3600sqft home, I'm wondering how many heat pumps it would take to replace my gas steam boiler system. I'm not s

by asow92 4y ago

As someone who lives in the northeast and has a 3600sqft home, I'm wondering how many heat pumps it would take to replace my gas steam boiler system. I'm not sure if heat pumps would be cost efficient given those parameters.

prottog 4y ago
In the Northeast with that much square footage, you would be better off with ground-source heat pumps (whether open or closed loop), rather than the normal air-source heat pumps.
- asow92 4y ago
  I guess the concern I have with all this is that my current system works well, and I don't want to spend $10K+ unless it brings down my heating costs significantly. Could a ground-source heat pump system do that?
  - zeroonetwothree 4y ago
    It depends on relative prices in your area so we can’t answer that. You would have to calculate it yourself. Typically it makes the most sense to do when you need to replace your system.
  - sbradford26 4y ago
    Ground source/geothermal would significantly reduce your heating costs but it would be significantly more than 10k. For that large of house something like 40k+ wouldn't be out of the question, with the largest expense being drilling. I personally think geothermal is great, sadly New England's geography makes getting a ground loop installed more difficult. In the midwest lots of people would do a horizontal loop by trenching like 8 feet underground laying pipe in there. In many parts of new england that isn't really viable with all the rock so vertical drilling is used which is significantly more expensive.
    - snuxoll 4y ago
      My brother-in-law lives in NE and has installed mini-splits and has overall enjoyed them. A ground source system would be "the best" for that region, but if you're not doing a new build then air source works just fine there with the correct equipment.
      - sbradford26 4y ago
        I also live in NE and we recently installed a mixed system. We have mini split units in the upstairs and a ducted air handler in the basement all attached to a cold weather heat pump outside. It has be working great for us so far, but we have the advantage of having a smaller house so we only needed one 4 ton unit outside. Our house was built in 1973 and originally had electric baseboards and then was converted to an oil boiler with hot water baseboard. So retrofitting a heat pump was an interesting task.
  - prottog 4y ago
    Like other commenters said, a GSHP will work excellently in terms of keeping you comfortable at a low ongoing price, but your initial costs will far exceed a $10k budget and you will likely never make that investment back ;-)
  - mikeyouse 4y ago
    What do you use to heat your water? If it's natural gas, it's likely close to making sense. If you use propane, it definitely makes sense to switch.
  - timbit42 4y ago
    A typical air-to-air heat pump has a CoP of 4 but the CoP goes down with the outside air temperature until the CoP becomes 1 at around -20C. Below that temp, you're better off using a backup heat source. A ground-source heat pump typically has a CoP of 5 but the CoP doesn't go down with the outside air temperature. Because the ground water temperature is stable, it will maintain its efficiency when it is cold outside. Of course, depending on the R value of your house, it may need to work harder to make up for the heat loss through the walls, roof and windows. You really need to find a heat pump installer who has the year round temperature data for your area and can do the math to calculate whether it is worthwhile to spend the extra on a ground-source heat pump.
elil17 4y ago
One* heat pump will do fine, but you might need a low temperature heat pump depending on where you are. After you factor in that gas is cheaper than electricity per kWh, the system should save you money as long as it is running at an efficiency higher than ~130%. A contractor should be able to select an appropriate system for you, but if you want to do it yourself, look for yourself, get the 2021 ASHRAE climatic design conditions for your area and choose a heat pump with a minimum operating temperature which is lower than the coldest month 99.6% heating drybulb temperature (DB) (should be the top row, left most temperature). *You would also need a fairly large heat pump, perhaps 7 tons (tons here means tons of refrigeration, or how many tons of ice the system can melt per day) depending on how well insulated you are.

by asow92 4y ago

prottog 4y ago

In the Northeast with that much square footage, you would be better off with ground-source heat pumps (whether open or closed loop), rather than the normal air-source heat pumps.

asow92 4y ago
I guess the concern I have with all this is that my current system works well, and I don't want to spend $10K+ unless it brings down my heating costs significantly. Could a ground-source heat pump system do that?
- zeroonetwothree 4y ago
  It depends on relative prices in your area so we can’t answer that. You would have to calculate it yourself. Typically it makes the most sense to do when you need to replace your system.
- sbradford26 4y ago
  Ground source/geothermal would significantly reduce your heating costs but it would be significantly more than 10k. For that large of house something like 40k+ wouldn't be out of the question, with the largest expense being drilling. I personally think geothermal is great, sadly New England's geography makes getting a ground loop installed more difficult. In the midwest lots of people would do a horizontal loop by trenching like 8 feet underground laying pipe in there. In many parts of new england that isn't really viable with all the rock so vertical drilling is used which is significantly more expensive.
  - snuxoll 4y ago
    My brother-in-law lives in NE and has installed mini-splits and has overall enjoyed them. A ground source system would be "the best" for that region, but if you're not doing a new build then air source works just fine there with the correct equipment.
    - sbradford26 4y ago
      I also live in NE and we recently installed a mixed system. We have mini split units in the upstairs and a ducted air handler in the basement all attached to a cold weather heat pump outside. It has be working great for us so far, but we have the advantage of having a smaller house so we only needed one 4 ton unit outside. Our house was built in 1973 and originally had electric baseboards and then was converted to an oil boiler with hot water baseboard. So retrofitting a heat pump was an interesting task.
- prottog 4y ago
  Like other commenters said, a GSHP will work excellently in terms of keeping you comfortable at a low ongoing price, but your initial costs will far exceed a $10k budget and you will likely never make that investment back ;-)
- mikeyouse 4y ago
  What do you use to heat your water? If it's natural gas, it's likely close to making sense. If you use propane, it definitely makes sense to switch.
- timbit42 4y ago
  A typical air-to-air heat pump has a CoP of 4 but the CoP goes down with the outside air temperature until the CoP becomes 1 at around -20C. Below that temp, you're better off using a backup heat source. A ground-source heat pump typically has a CoP of 5 but the CoP doesn't go down with the outside air temperature. Because the ground water temperature is stable, it will maintain its efficiency when it is cold outside. Of course, depending on the R value of your house, it may need to work harder to make up for the heat loss through the walls, roof and windows. You really need to find a heat pump installer who has the year round temperature data for your area and can do the math to calculate whether it is worthwhile to spend the extra on a ground-source heat pump.

elil17 4y ago

One* heat pump will do fine, but you might need a low temperature heat pump depending on where you are. After you factor in that gas is cheaper than electricity per kWh, the system should save you money as long as it is running at an efficiency higher than ~130%. A contractor should be able to select an appropriate system for you, but if you want to do it yourself, look for yourself, get the 2021 ASHRAE climatic design conditions for your area and choose a heat pump with a minimum operating temperature which is lower than the coldest month 99.6% heating drybulb temperature (DB) (should be the top row, left most temperature). *You would also need a fairly large heat pump, perhaps 7 tons (tons here means tons of refrigeration, or how many tons of ice the system can melt per day) depending on how well insulated you are.