About Us


G.O. Loop LLC was started in 2005 and has been growing steadily ever since. We specialize in closed loop installations and have installed over 2,000 such systems. We will install any loop system from small residential installations up to large scale commercial applications. Our projects involve vertical drilling, directional drilling, trench excavation or pond installation.  We have design software and experience for residential/light commercial loop fields as well as for large commercial projects. For large scale projects, we also have the equipment and knowledge to conduct soil conductivity tests. For a list of commercial projects completed and projects in progress, please see our Commercial page.


Gordy Oosterhouse is the founder of G.O. Loop and worked with geothermal systems ever since his first installation as a HVAC Contractor in 1994. Brandt Eisenga has been with the company since 2008, became partner in 2019 and now serves as general manager and runs the residential projects. Brandt is also a past board member for the Wisconsin Geothermal Association. Colton Sherwood started with G. O. Loop in 2021 and is the commercial project manager. Brandt, Colton and several of our other employees have IGSHPA training and certification. IGSHPA stands for International Ground Source Heat Pump Association. This is an association which promotes, educates and regulates the geothermal industry. We are members of both the Wisconsin Geothermal Association and the Wisconsin Builders Association and we are also accredited with the Better Business Bureau of Wisconsin. We are located in South-Central Wisconsin and service the entire state as well as parts of northern Illinois.

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