How is efficiency rated for geothermal?
All heating and cooling
systems have a rated efficiency from a U.S. government agency. Fossil fuel
furnaces use AFUE. Air conditioners use SEER while heat pumps use HSPF and
SEER.
Geothermal heat pumps rate
heating efficiencies according to their coefficient of performance or COP. It’s
a scientific way of determining how much energy the system produces versus how
much it uses. Most geothermal heat pump systems have COPs of 3-4.5. The
WaterFurnace Envision holds the highest recorded certified performance of 5.4
COP in an open loop. That means for every dollar of energy used to power the
system, $5.40 of energy are supplied as heat. Where a fossil fuel furnace may
be 78-98% efficient, a geothermal heat pump is about 500% efficient.
For cooling, geothermal units
are rated by Energy Efficiency Ratio (EER). EER is a measure of efficiency in
the cooling mode when measured at a constant temperature (95 degrees F). The
higher the EER, the more efficient the unit. The WaterFurnace Envision holds
the highest recorded certified performance of 30EER for closed loop and 32.1EER
for open loop.
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