The earth 6 feet below your backyard stays at a constant 50–60°F year-round. A ground-source heat pump taps this resource for dramatically efficient home heating and cooling — and DIY installation is possible.
A ground-source heat pump (GSHP) doesn't generate heat — it moves it. In winter, it extracts heat from the relatively warm earth (50–60°F) and concentrates it to heat your home. In summer, it runs in reverse, moving heat from your home into the earth — providing cooling.
Efficiency is measured by COP (Coefficient of Performance): a COP of 3.5 means for every 1 kWh of electricity consumed, 3.5 kWh of heat energy is delivered. Compare to: electric resistance heat (COP 1.0), air-source heat pump (COP 2.0–3.5 in mild weather).
Ground-source systems maintain COP 3.5–5.0 year-round because ground temperature is consistent — unlike air-source, which drops in efficiency on very cold days.
| Loop Type | Land Required | Cost | DIY Feasible |
|---|---|---|---|
| Horizontal (6ft depth) | Moderate (2× home sq ft) | $10–20/ft trench | Yes — with equipment rental |
| Vertical (200ft bore) | Minimal | $15–25/ft boring | Requires drilling rig |
| Pond/lake loop | Water body on property | Low | Yes — if you have water |
| Direct exchange (DX) | Moderate | Medium | Complex refrigerant work |
A horizontal ground loop is the most accessible for DIY installation. The loop consists of HDPE pipe buried 4–6 feet deep in trenches, through which a water/antifreeze mixture circulates.
Sizing: For every ton (12,000 BTU) of heating/cooling capacity, horizontal loops typically require 150–300 feet of trench (with 2 pipes per trench = 300–600 feet of pipe).
DIY approach:
The heat pump unit itself is typically a purchase or installation job — DIY is most applicable to the ground loop (the most expensive part of a professional installation).
| Component | Professional Install | DIY Portion |
|---|---|---|
| Ground loop excavation | $8,000–15,000 | $1,500–3,000 (rented equipment) |
| HDPE pipe and fittings | Included above | $500–1,500 |
| Heat pump unit (3 ton) | $4,000–8,000 (w/labor) | $2,000–4,000 (unit only) |
| Installation/mechanical | $3,000–6,000 | $500–1,500 (licensed HVAC for final) |
| Total | $20,000–40,000 | $5,000–10,000 |
Federal tax credits (30% ITC) apply to geothermal heat pump installations — reducing the effective cost significantly.
If a full GSHP is too complex, consider these simpler ground-thermal strategies: