Geothermal Heat Pumps
Before you buy a heat pump
- Compare alternatives (such as a high-efficiency gas furnace), especially if natural gas is available.
- Compare environmental claims carefully.
- Contact the Wisconsin Geothermal Association for a list of experienced professionals.
- Make sure your home is well insulated and air sealed, with good ventilation regardless of what type of heating system you choose. If your new home doesn't require much heat, the type of heating system you choose becomes less important.
- If the building is new, see MGE's New Home Planner [3.0 MB PDF] for recommendations.
- Learn more about the basics.
Why is further geothermal heat pump research needed in cold climates?
The measured performance of geothermal heat pumps in cold climates in studies that we are aware of suggests that heat pump systems don't work as efficiently as people would expect. We also have heard from customers who have geothermal heat pumps and are unhappy because they see higher heating costs than they expected.
Help MGE learn more
Know of a house that's switched from a natural gas to a geothermal heat pump in MGE's service area? Please call us at (608) 252-7117 with the address! We're particularly interested in comparing heating costs before and after the geothermal heat pump was installed.
Resources and further reading
- These two cold-climate field studies found that measured performance is lower than the performance ratings published by manufacturers. (Similar to the way real-world mileage differs from the mileage-rating stickers on cars).
- Energy Center of Wisconsin analysis [319 kB PDF] says modeled dollar savings and environmental benefits are small for residential geothermal heat pumps.
- Building Science Corp. Digest #113: "This digest provides some basic information and definitions, offers advice on how to compare the carbon emissions, and defines the climate regions and operating conditions for which (geothermal heat pump) systems are best suited." And, "There has been a recent surge of interest in Ground Source Heat Pump (GSHP or "geothermal" or GeoExchange™) systems for residential projects. Outrageous claims and misunderstandings about how they work are common."
- Green Building Advisor article.
- Minnesota Sustainable Housing Initiative article.
- Dept. of Energy Geothermal Heat Pump information.
- A geothermal heat pump "survival kit" [229 kB PDF], including economic comparisons. Published in 2001, it still has useful information.
- The International Ground Source Heat Pump Association actively promotes geothermal heat pumps.
- The Wisconsin Geothermal Association promotes ground source heat pumps and publishes "How to Choose a Pro."
Federal tax credits are available on geothermal heat pumps through 2016.