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System Design


As you go through the different ways to heat and cool your home with renewable electricity there is a process to make sure that the system you decide to install can meet all of your heating and cooling demands everyday of every year. This is based on where your house is located, what it is built of, windows, doors, exposure to the sun and most importantly insulation values. This analysis is called a heat loss heat gain calculation. Whether your existing home or new build is best suited for a ground source heat pump or an air source heat pump the amount of heating and cooling your dwelling will need does not change - just the equipment that will work best for your home. Our designers are TECA Quality First Certified in Heat Loss/Gain calculations as well as Heat Recovery Ventilation and Ducting and Venting.



Both air source heat pumps (ASHP) and ground source heat pumps (GSHP) use the same compressor, refrigeration, heat exchange technology. The only real difference is that air source moves heat in and out of your house and exchanges it with the outside air whereas ground source exchanges the heat in your house with the ground. When an air source heat pump is cooling (much like a refrigerator) it is collecting the warmer air in your house and extracting that heat and dumping outside into the air. When heating the ASHP is taking heat from the outside air and bringing it into your house. This technology works great especially when the ambient air temperture is not to far from the desired temperature of your home. As one can imagine as it gets colder outside it becomes more difficult to extract heat from air that is - 20 C.


What a ground source heat pump does is it uses the ground which is  at a constant temperature in the Okanagan of between 5 and 15 C  (40 - 60 F) as the heat exchanger. So as the temperature outside falls below zero the ground temperature remains roughly constant. So as the ASHP above works to extract heat from air that is - 15 C the GSHP is working more efficiently to extract heat from the ground which is still sitting at + 10 C. So that is the advantage of  Ground Source over Air Source. That being said both technologies will heat and cool your house at every temperature and there are other things to consider.

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Ground Source Heat Pumps require the use of the ground. That means that Terra Geothermal has to install an energy well which will be either horizontal (more cost effective) or vertical (requires drilling). The decision between ASHP and GSHP requires a person to person conversation based on your expectations for efficiency, the type of property you are building on and your budget. Terra Geothermal does both ASHP and GSHP so that you get the best most cost effective and efficient renewable energy heating and cooling system for your house. Whether you are building a new home or retrofitting an old home we have the solution that is correct for you.

Terry J. Watson
Partner & Designer
Geoexchange Designer - 13 years
TECA - HRV Design
TECA - Heat Loss Heat Gain
Solar - Installer Course
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