The U.S. Army installation in Lawton, Oklahoma is replacing conventional HVAC systems with ground-source heat pumps across its entire residential portfolio. The project represents one of the largest military geothermal retrofits to date and offers a real-world case study for contractors evaluating commercial-scale ground-source work.

Geothermal heat pumps move heat between the earth and the building rather than generating it through combustion or resistance. At Fort Sill, the installation involves drilling vertical boreholes 150 to 400 feet deep, installing closed-loop polyethylene piping, and connecting each home to a water-to-air heat pump. The ground maintains a stable 50-60°F year-round in Oklahoma, which allows the system to operate at COP values between 3.5 and 4.5 depending on load — significantly higher than air-source equipment in summer peak conditions.

The 57 percent energy reduction figure accounts for both heating and cooling across mixed construction types, including wood-frame duplexes and masonry townhomes built between the 1970s and 2000s. Annual savings of $5 million translate to roughly $2,940 per home per year, driven by eliminating natural gas service and cutting electric demand during the Oklahoma summer when air-source systems struggle with 100°F+ ambient temperatures.

What Contractors Should Know This Week

If you're quoting geothermal projects — residential or light commercial — the Fort Sill numbers provide benchmarking data for proposals. Expect installed costs between $35,000 and $40,000 per home for turnkey ground-source retrofits at scale, including loop field, heat pump, ductwork modifications, and electrical upgrades. Payback periods in military and institutional settings typically run 8 to 12 years, but federal incentives under the Inflation Reduction Act now cover 30 percent of qualified costs through 2032, which brings residential geothermal into the conversation for high-end replacement jobs and new construction.

Stock extended-range water-to-air heat pumps rated for closed-loop operation if you're pursuing geo work. Equipment must handle antifreeze mixtures — typically 15 to 25 percent propylene glycol — and integrate with variable-speed ECM blowers for part-load efficiency. Contractors entering the geothermal space should partner with certified drillers and loop designers; the International Ground Source Heat Pump Association offers accreditation programs that separate qualified installers from those learning on the job.

The Fort Sill project also signals growing federal and state interest in electrification at scale. Watch for similar RFPs from military installations, universities, and housing authorities over the next 24 months as decarbonization mandates accelerate.