Geothermal energy is thermal energy generated in the Earth, but when it comes to residential homes, it always refers to a system that uses piping buried in the ground to extract heat from the earth.
Geothermal system uses loop of piping that is buried outside of the home in order to extract heat from the ground, or deposit heat to the ground, depending on which mode the system is, heating or cooling. The loop piping is typically installed in a series of trenches.
Geothermal systems can be used instead of furnaces, air conditioners, boilers and domestic water heaters. They can also be used for driveway snow melting systems or swimming pool heating systems.
Components of geothermal heating and cooling systems always include a heat pump, recirculation pump and ground loop. If it is used to heat water for drinking, bathing and other purposes the system would include one water storage tank or more. Some water heating systems use a dedicated heat pump for heating domestic water.
The benefits of geothermal heat pumps.
Compared to natural gas, the cost to operate geothermal systems can present a 50% savings in heating costs over a year.
What does a home inspector do when inspecting a geothermal system?
Geothermal systems are complex, and the service covers or panels of them aren’t designed to be opened by homeowners or home inspectors, so we do not open them. But there are several items that we check and advise on:
Heat pumps are inspected for physical damage
Electrical breakers, connections and wiring are inspected
Outside loop areas that are visible in the basement or crawlspace are checked for leaks and to ensure that they are insulated
The foundation wall outside loop penetrations are inspected for adequate waterproofing and for signs of leaking
Condensate overflows are inspected to ensure that they are not clogged or otherwise backed up
If the outside loop is un-pressurized (as most are) open the circulation pump and check the water level
If a heat pump for domestic hot water is present, we inspect the storage tank or secondary water heater.
During the heating season we turn the thermostat up and attempt to test the emergency heat feature. We only do this briefly, and return the thermostat to its original setting after inspection.
Only during the cooling season, we make sure that cooling system is working
We walk through the home and test all the supply and return registers for air flow.