Energy Star - Heat Pumps and Geothermal
List of the most efficient ground source heat pump systems and efficiency performance criteria.

Energy Star - Quality Installation Checklist (.pdf)
This checklist may be useful when soliciting bids from contractors to help ensure that your system is properly installed. 

Energy Star - Ten Tips for Hiring a Heating and Cooling Contractor
Things to look for when selecting an installer. 

Geothermal Heat Pump Overview
A general website, with links to information on different system types and resources for selecting installers, from the U.S. Department of Energy.

Geothermal Heat Pumps for Homeowners
General information on ground source heat pump systems from the National Renewable Energy Laboratory.

International Ground Source Heat Pump Association (IGHSPA)
List of IGSHPA accredited installers in Minnesota and other ground source heat pump information resources. 

Licensed or Registered Well Contractor Directory
Ground source heat pumps that use vertical wells must be installed by a contractor who is licensed and bonded by the Minnesota Department of Health (MDH). You must also obtain a permit from MDH before starting the work.

North American Technical Excellence
Search by zip code for heating, ventilation, and air conditioning (HVAC) contractors in your area who employ technicians who have been certified by North American Technician Excellence (NATE).

Pros and Cons of Geothermal Heating and Cooling Systems
This Minnesota Department of Health site gives an overview of the different types of ground source heat pump designs including those with the potential for adverse environmental impacts. Descriptions and references to state requirements for vertical bore ground source heat pump systems are also included.

What should I know about installing a geothermal system?
Minnesota Department of Natural Resources requirements for installing "pump and dump" and pond-loop systems (see document for more information on these system types).