Geothermal Heat Pumps

Geothermal Heat Pumps are an energy efficient means of heating and cooling a home and can also be used for hot water.  They work with both hydronic and forced air systems.  Forced air systems provide for both heating and cooling, whereas hydronic systems are typically used for heat only.  Hydronic systems are typically radiant floor heating systems, but could also utilize fan coils units.  Geothermal Heat Pumps essentially take heat from the earth during the winter and transfers it into the home, and during the summer transfer the heat from the home into the earth.

The system is comprised of three components.

1. Ground Coupling - essentially a well with either a closed or open loop piping.
2. Heat Pump - either water to air for forced air systems or water to water for hydronic systems
3. Distribution System - either ducting for forced air systems or piping for hydronic systems 

First Costs
As with standard heating systems, the size of the systems varies with the size of the house and the amount of insulation in the home.  With geothermal systems, a well will also be required. In some circumstances, the drinking water well can be used for the heating system as well.   Most homes will need a 3 - 6 ton system for heating and cooling loads.  Depending upon the well and "ground coupling" type, the overall system costs range from $800 - $3,500 per ton.
Currently, the federal government is offering a 30% tax rebate for residential geothermal systems.

Operating Costs

The operating costs of these systems are typically quite low.  For every unit of electricity that is used for heat, the systems is able to pull for units of heat out of the earth.  The break even costs vary based upon the prices of electricity, propane, oil, and natural gas.  In 1993, the EPA conducted a study in Burlington, VT to evaluate the efficiencies and cost of different types of heating and cooling systems.  They found the geothermal heat pump had the lowest operating costs as seen below.

• Geothermal - under $900/year
• Gas furnace with central air - approximately $1100/year
• Oil furnace with central air - approximately $1300/year
• Air source heat pump - nearly $1500/year