With energy costs on the rise and tax credits available, many people have opted to use geothermal residential systems as a source of heating and cooling for their homes. But is it really worth it?
Geothermal systems use the earth’s temperature to aid in the cooling or heating of a home’s heat or cooling system. To heat by use of a water or air loop buried in the ground below the frost line, the system absorbs the temperature of the ground and brings it using convection into the heating coils of a heat pump.
The advantage is the heating or cooling coils absorb the ground’s or home’s heat and transfers it to the other location. This effectively either heats or cools the home. That all sounds great! The heat pump does not have to work as hard for the cooling or heating coil to perform. The heat pump can then use that energy to blow air across the coil or through a water or glycol tank, which can be circulated through radiant floors or wall radiators.
That is a very attractive proposition, with current tax incentives of 30% or greater taken on the entire system: Loops, heat pumps, supplement heating elements, and other components of the system. So what is the downfall?
Many times, a system of loops in a drilled format will cost in the 10’s of thousands of dollars for the drilling and vertical loop layouts. The heat pump equipment is slightly more costly than an average furnace or boiler system—except for higher performance furnace and boiler equipment, and then the cost is similar. Ductwork and/or heat piping will still be the same cost whether a conventional system or Geothermal.
But here is another consideration: the pumps, used to keep the water or the air moving through the earth generally all the time. Many times those pumps are larger than necessary and poorly controlled. To make a system truly work a good control system needs to be established that will turn pumps on so the system meets the home’s demands and to turn off equipment when desired climate conditions can be meet without the need for heating or cooling. If that control is not properly designed into the overall system, you will simply be paying for a sophisticated system that unnecessarily runs 24-7 and 365. That electric usage will far out strip the savings of using the earth’s natural temperature.
Article by Larry Gilland, LGA Studios