About Home Inspection
Home Inspection Legislation

Kaplan Graduate Benefits

Inspector Tech Support

Inspection Report Newsletter

Inspection Tips Free E-Newsletter

Inspection Industry Events
Articles & Press Releases
Errors & Omissions Insurance
Classified Ads / Help Wanted
Free Online Advertising
Realtor Resources
Inspector's Resource Guide
Site Map


Kaplan ITA's Monthly Inspection Tips - Free Electronic Newsletter

January, 2008
Geothermal Heat Pumps
Issue #69

This month, by request, I would like to discuss the basics of Geothermal Heat Pumps (also known as ground source heat pumps). While initial installation cost for these systems is about twice or more a typical air to air system, the cost to operate is much less than a standard system and the payback in energy cost savings can offset the installation cost.

Geothermal heat pumps use typical vapor compression to move heat, just like air to air units. The key difference is the reliability of the heat source/dump. Air to air systems rely upon the outdoor air temperature as a source/dump, which can vary widely, even so cold as to be below the “balance point” of the equipment, when supplemental heat is then required, usually electric resistance strip heaters. Geothermal systems use the soil as their heat source/dump. Below about six-feet the soil just about anywhere is a reliable 45 to 70 degrees F. Obviously much less swing than the outdoor air. Because of this the heat pump can obtain heat more readily than the outdoor air as well as dump heat to a much cooler material than the outdoor air in summer.

In order to access the ground source vertical pits or horizontal trenches are dug. Inside these holes are installed loops in which water or a water/glycol mix is circulated during unit operation. Inside the internal unit of the heat pump is a heat exchanger wherein the heat is moved from the refrigerant to the liquid ground loop and transferred. Because of the much more reliable temperature of the soil the heat pump does not have to work as hard then an air to air unit.

We also can use ground source heat pumps to provide domestic hot water using the same process. Many units are combination and provide many needs, including hot water, heat and cooling, even pool heating.

A water source heat pump uses the same technology as above, only the outdoor liquid loops are installed in vertical wells or in a pond.

For more information on this technology http://geoexchange.us is a great source.

Mike Casey
Kaplan Professional Schools


Featured Resources

200 Series Online courses
Residential Energy Inspections with Home Tune-uP® course

Advertising Opportunities Available

A Kaplan Professional Company.   © 2004, DF Institute, Inc. All rights reserved. Call Toll-Free: 1-888-323-9235