Free, Renewable Energy From the Earth

Almost all buildings need heating and / or cooling to keep occupants comfortable. Office buildings, schools, homes, condos, churches, manufacturing plants, retail spaces... all need to be conditioned. Many need domestic hot water, refrigeration, process cooling, etc. Using the ground under and around the buildings allows you to reduce the amount of energy you need to purchase... reducing energy cost and impact on the environment.

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Weber State University Thermal Highway, Ogden, Utah

Central system that is using the chilled water distribution system for about 75% of the year. This project will phase out the chillers and boilers and be 100% convective circulation circuit by 2025.

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About Us

Unparalleled ground source system experience

The members of the GreyEdge Group have all been committed to the ground source heat pump industry for many years. A combined total of over 250 years of experience in almost all facets of the industry around the world from projects ranging from single family homes to large district geothermal systems, give us unparalleled expertise in one of the most energy efficient heating and cooling technologies available.

The GreyEdge Team

Garen Ewbank B.S. I.E.&M, OSU, AEE Fellow
Don Penn PE, CGD, CGI, AEE Fellow
Stephen Hamstra PE, AEE Fellow, ASHRAE HBDP, CGD, LEED AP
Cary Smith CEM, CEA, CGD, CGI, AEE Fellow

Image Engineering Group, Ltd.


Successful projects around the world

GreyEdge members have been involved in geothermal heat pump projects around the world...North America, Asia, Australia and Europe. Projects ranging from single family homes, schools, recreation facilities, retail, offices, religious facilities...through to district geothermal energy utilities that move waste energy through a project rather than waste it.

Visit our Member Websites for More Projects


For more information email us here or use one of the methods below.

Main Office

Cary Smith
The GreyEdge Group, LLC
3962 E. Alpine Valley Circle
Sandy, UT 84094
Phone: 801-942-6100
Fax: 801-942-6127


Paul Bony
The GreyEdge Group, LLC
3962 E. Alpine Valley Circle
Sandy, UT 84094
Phone: 801-942-6100
Fax: 801-942-6127


Garen Ewbank
The GreyEdge Group, LLC
115 Woodcreek Drive
Fairview, OK 73737
Phone: 580-227-2358


William (Bill) O’Donnell
The GreyEdge Group, LLC
545 W. 19th
Idaho Falls, Idaho 83402
Phone: 208-523-8068


Don Penn
The GreyEdge Group, LLC
1301 Solana Boulevard
Building 1, Suite 1420
Westlake, Texas 76262
Phone: 817-410-2528


Gary Sexton
The GreyEdge Group, LLC
1870 Optimus River Road
Calico Rock, AR 72519
Phone: 870-297-8604


Stephen Hamstra
The GreyEdge Group, LLC
Phone: 616-566-6185

New York

Jerry Acton
The GreyEdge Group, LLC
Phone: 607-657-8622
Fax: 607-398-1450