This was a very interesting session. As a homeowner who has a GSHP I have some experience that may be of value to those considering going with this technology. Capable installation and maintenance company - this is not a project for a rule of thumb installer. Having been down this road it is my experience that there are very few installers who really understand how to design a system that will work properly. Most can figure out how to do the installation. Make sure your installation company can do maintenance and is likely to exist in the future. Make sure they have an emergency number and when you speak to reference customers (you are going to ask for reference customers right?) ask how responsive the company was when something broke, how long did it take to do the repair, how easy was it to get replacement parts. New Build * Floor or Ceiling radiant is the best for heating - recognize that to add cooling you may need a separate forced air system. If you go strictly with forced air be aware that with the cooler temps your heating will feel like a draft when it is running...it can be uncomfortable. * Spare no expense in getting your new house insulated and sealed to the tightest degree possible...this will reduce capital and operating costs and dramatically increase comfort. * Get an expert opinion on whether it makes sense to install a GSHP vs an ASHP to your super insulated home before making any decision on what system to go with. Air source systems have come a long way and there are some Air to water systems that can be used for radiant and forced air. Retrofit * Existing ducting may be too small for forced air GSHP/ASHP heating resulting in the need for either new ducting or significantly increased air velocity with resulting noise and feeling of draftiness. Don't assume that the ducting in your home was done properly....it probably wasn't and a low temp heat pump solution will really emphasize that shortcoming * Before you spend a fortune on a GSHP solution upgrade your insulation and air sealing, including windows and doors, to the highest degree possible...this should result in the need for a smaller GSHP, smaller outside loop and will result in lower bills and increased comfort. If you are thinking of adding an extension make sure you do it before the GSHP project....expanding a GSHP system is not trivial. Design * If you go into this understanding that the design is critical for the system to be efficient and reliable then you will also understand that proper design costs money....make sure you compare apples to apples when comparing quotes...ask the sales person to explain their quote if it's much lower or much higher than other quotes.... the higher one may be the only company doing a proper design. * Radiant and or ducting infrastructure must be designed to match the heat loss and cooling loads of your house which should include a full assessment of every room in your house * Size of the GSHP needs to be accurately matched to the needs of your house...too big and it will be cycling and wasting energy, too small and it wont be able to keep up with demand. You may need auxiliary heat (Plenum electric coils) for the coldest days in order to ensure your system isn't too big - again, a super insulated home is less likely to need this expensive option. * Outside loop must be matched to the GSHP and take into account the soil conditions...too big and there are pumping losses, too small and the system wont be able to keep up with demand. Make sure you go with a reputable installation and maintenance company that is selling quality components with a reputation for efficient systems that are reliable. Ideally there will be more than one maintenance company in your area that can service the GSHP product that you choose....don't assume there will be...make sure there will be. It seems expensive, is it worth it? Yes, if done correctly your operating costs will be very low and your comfort level high. You will have significantly lowered your contribution to our CO2 emissions and you have set yourself up to benefit from the installation of solar panels if you have that option sometime down the road.
This was a very interesting session. As a homeowner who has a GSHP I have some experience that may be of value to those considering going with this technology.
Capable installation and maintenance company - this is not a project for a rule of thumb installer. Having been down this road it is my experience that there are very few installers who really understand how to design a system that will work properly. Most can figure out how to do the installation. Make sure your installation company can do maintenance and is likely to exist in the future. Make sure they have an emergency number and when you speak to reference customers (you are going to ask for reference customers right?) ask how responsive the company was when something broke, how long did it take to do the repair, how easy was it to get replacement parts.
New Build
* Floor or Ceiling radiant is the best for heating - recognize that to add cooling you may need a separate forced air system. If you go strictly with forced air be aware that with the cooler temps your heating will feel like a draft when it is running...it can be uncomfortable.
* Spare no expense in getting your new house insulated and sealed to the tightest degree possible...this will reduce capital and operating costs and dramatically increase comfort.
* Get an expert opinion on whether it makes sense to install a GSHP vs an ASHP to your super insulated home before making any decision on what system to go with. Air source systems have come a long way and there are some Air to water systems that can be used for radiant and forced air.
Retrofit
* Existing ducting may be too small for forced air GSHP/ASHP heating resulting in the need for either new ducting or significantly increased air velocity with resulting noise and feeling of draftiness. Don't assume that the ducting in your home was done properly....it probably wasn't and a low temp heat pump solution will really emphasize that shortcoming
* Before you spend a fortune on a GSHP solution upgrade your insulation and air sealing, including windows and doors, to the highest degree possible...this should result in the need for a smaller GSHP, smaller outside loop and will result in lower bills and increased comfort. If you are thinking of adding an extension make sure you do it before the GSHP project....expanding a GSHP system is not trivial.
Design
* If you go into this understanding that the design is critical for the system to be efficient and reliable then you will also understand that proper design costs money....make sure you compare apples to apples when comparing quotes...ask the sales person to explain their quote if it's much lower or much higher than other quotes.... the higher one may be the only company doing a proper design.
* Radiant and or ducting infrastructure must be designed to match the heat loss and cooling loads of your house which should include a full assessment of every room in your house
* Size of the GSHP needs to be accurately matched to the needs of your house...too big and it will be cycling and wasting energy, too small and it wont be able to keep up with demand. You may need auxiliary heat (Plenum electric coils) for the coldest days in order to ensure your system isn't too big - again, a super insulated home is less likely to need this expensive option.
* Outside loop must be matched to the GSHP and take into account the soil conditions...too big and there are pumping losses, too small and the system wont be able to keep up with demand.
Make sure you go with a reputable installation and maintenance company that is selling quality components with a reputation for efficient systems that are reliable. Ideally there will be more than one maintenance company in your area that can service the GSHP product that you choose....don't assume there will be...make sure there will be.
It seems expensive, is it worth it?
Yes, if done correctly your operating costs will be very low and your comfort level high. You will have significantly lowered your contribution to our CO2 emissions and you have set yourself up to benefit from the installation of solar panels if you have that option sometime down the road.
Still wondering about the effects of in-ground heat pumps on tree roots