Economic Benefits

Not only does a geothermal heat pump save energy, but that also means it saves you money on your annual heating, cooling, and hot water costs.  Geothermal heat pumps have been proven to save you as much as 30-70% annually.  This varies depending on what the geothermal system is being compared to.

Heating Comparison:

Here are some examples of the efficiency comparisons of different types of heating equipment:

Heat Energy Flow Diagram

The efficiency is directly related to how much energy is delivered vs. how much is purchased.  For example, an efficiency of 97% equals $1 of energy purchased to $.97 of energy delivered.  That system is providing less energy than what was supplied.  A geothermal heat pump at it’s worst case scenario would be 350% efficient so that equals $1 of energy purchased to $3.50 of energy delivered.    Depending on fuel costs and the efficiency of the systems being compared the savings would be between 30-70%.

Cooling Comparison:

For cooling it is a easier comparison since both technologies are using the same principle.  The only difference between a standard central AC system and a geothermal heat pump is the source to which the energy is being rejected.  An AC system is sitting outside during the hot summer days trying to cool your home.  It is trying to remove heat from your home at 75-78F and reject that energy into the 90-95F summer heat.

A geothermal heat pump is using the stable cool ground temperature of 48-52F to reject that 75-78F energy.  Because we are moving heat energy to a cooler place the efficiencies are improved, plus the GSHP is using water vs. air to move the energy which is a more efficient way to do so.  Therefore, a typical AC may have a SEER rating of 14-16, but a geothermal heat pump system in Minnesota will have  a EER rating of 20-30.  That is over twice the efficiency, plus you get the added benefit of the hot water generator on the geothermal system which is taking the waste heat from cooling your home and rejecting that heat into your water heater.  You are already paying to cool your home, so this is free energy that is being delivered to make hot water.

Water Heating Comparison:

Water heating devices operate at about the same efficiencies as heating appliances.  So gas units will range from 75-95% efficient and electric units will be 100% efficient.  A geothermal system utilizing a desuperheater or hot water assist mechanism can produce 130F water for your domestic supply free in the summer mode, and with a COP of at least 3 in the winter mode.  However, this type of setup is only in operation when the system is heating or cooling the home.  Because of where the desuperheater coil is located inside the heat pump, it is not able to generate hot water if the unit is not heating or cooling the home.  Therefore, the geothermal system and desuperheater can save you up to 60% on your hot water costs per year.

Compare the costs of energy for heating:

Cost per Million BTU

This chart shows the fuel costs to purchase 1 million btu’s with each of the different heating devices, and their respective efficiencies, at current utility rates in the region.  During the heating season, the average home in Minnesota uses 75-100 million btu’s.  If you take the cost per million and multiple it by 100 that would equal your total heating costs for the year (example for GSHP = $6.25 x 100 = $625.00/year).  This is an estimation for total operation, but does not figure all costs associated with the ASHP, NG, LP, or Fuel oil furnaces, due to electricity needed to operate the fan motor, combustion motor, and supplemental heat source for the ASHP.