How long do geothermal heat pumps last?

The indoor heat pump unit typically lasts 20-25 years with proper maintenance, while the ground loop can last 50+ years since it's buried underground with no moving parts. This long lifespan is one of geothermal's key advantages over conventional HVAC.

What COP is realistic for a geothermal system?

Modern ground-source heat pumps achieve COP 3.5-5.0 for heating. A COP of 4.0 means the system delivers 4 units of heat for every 1 unit of electricity consumed — roughly 400% efficiency. Values above 5.0 are achievable in mild climates with optimal loop design.

Is geothermal better than a regular heat pump?

Geothermal systems are 30-60% more efficient than air-source heat pumps because they exchange heat with the ground (50-60°F year-round) rather than outdoor air (which can be 0°F or 100°F+). The tradeoff is higher upfront cost for lower operating costs and longer equipment life.

Do I need a large yard for geothermal?

Horizontal ground loops need roughly 1,500-2,500 sqft of open land per ton of capacity. A typical 3-ton system needs about 4,500 sqft (a quarter acre). If yard space is limited, vertical bore loops use much less surface area but cost more to install due to drilling.

Calculator

Geothermal Heat Pump Sizing Calculator

Size a ground-source heat pump and estimate savings vs gas heating

Geothermal heat pumps use the earth's stable underground temperature to heat and cool your home far more efficiently than conventional systems. This calculator sizes a ground-source heat pump based on your home's heating and cooling load, then estimates annual operating costs and compares them against a standard 80% AFUE gas furnace plus 13 SEER air conditioner. You get projected annual savings, payback period on the installation investment, ground loop sizing, and a 10-year financial outlook. Whether you're evaluating geothermal for a new build or retrofitting an existing home, this tool gives you the numbers to make a grounded decision.

Federal residential clean energy credit rules changed for 2026 — no credit is assumed by default. Read the policy details

Enter Your Details

Fill in the form and click Calculate to see results.

Policy status

Geothermal federal incentive policy status

Federal residential clean energy credit assumptions now depend on the project year. RenewableCalc does not automatically apply a 30% federal residential credit to 2026+ projects; verify current IRS rules, tax eligibility, utility programs, and local incentives before treating an estimate as final.

Policy last reviewed: 2026-06-09 · Source label: IRS Residential Clean Energy Credit and current federal incentive guidance.

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Geothermal economics vary significantly by region and existing HVAC system.

How to Use This Calculator

Enter your home's square footage — this determines the heating and cooling load using the 30 BTU/sqft rule of thumb common in US residential HVAC sizing. Set your electricity rate ($/kWh) from your utility bill. COP (Coefficient of Performance) should be 3.5-5.0 for modern ground-source heat pumps; check the manufacturer's spec sheet. EER (Energy Efficiency Ratio) for cooling typically runs 16-25 for geothermal systems.

Enter your annual heating and cooling hours based on your climate zone — the calculator defaults to 1,500 heating hours (roughly climate zones 4-5) and 800 cooling hours. Fill in the installation cost, which typically ranges from $15,000-$40,000 depending on home size and local geology. Finally, enter your local natural gas price per therm for the conventional comparison.

The results show annual operating costs, savings versus gas heating, payback period, ground loop length needed, and 10-year cumulative savings.

Formula & Methodology

Heating Load (BTU) = Home Size (sqft) × 30 BTU/sqft
Heating Load (kW) = Heating Load (BTU) / 3412

Geothermal Costs:
  Heating Cost = (Heating Load kW / COP) × Electric Rate × Heating Hours
  Cooling Cost = (Heating Load kW / (EER × 0.293)) × Electric Rate × Cooling Hours
  Total Annual = Heating Cost + Cooling Cost

Conventional Comparison (80% AFUE gas + 13 SEER AC):
  Gas Heating = (Heating Load BTU × Heating Hours / 100,000) × Gas Price / 0.80
  AC Cooling = (Heating Load kW / 3.5) × Electric Rate × Cooling Hours
  Conventional Annual = Gas Heating + AC Cooling

  Annual Savings = Conventional Annual − Total Annual
  Payback = Installation Cost / Annual Savings

Ground Loop:
  Tons = Heating Load BTU / 12,000
  Feet = Tons × 200 (approx 200 ft per ton of capacity)

COP (Coefficient of Performance) is the ratio of heating output to electrical input for the heat pump. EER (Energy Efficiency Ratio) measures cooling efficiency. Higher values mean lower operating costs. The calculator uses industry-standard conversions: COP 4.0 = roughly 13.6 EER, and 13 SEER ≈ EER 11.

Frequently Asked Questions

Residential geothermal systems typically cost $15,000-$40,000 installed, including the ground loop and indoor equipment. The wide range depends on home size, loop type (horizontal vs vertical), local drilling costs, and soil conditions. Project-year federal incentive eligibility can materially change net cost; 2026+ residential projects should not assume a federal residential credit without current IRS support.

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