HeatPumpLab

Geothermal vs. Air-Source Heat Pump Cost Calculator

Compare a ground-source (geothermal) heat pump to an air-source heat pump on annual operating cost, upfront cost, simple payback, and 15-year total cost.

The short answer

Geothermal heat pumps always run cheaper than air-source — typically 25% to 50% less per year — because ground temperatures stay stable while air-source efficiency falls in the cold. But geothermal costs $15,000 to $25,000 more upfront for the ground loop. The federal residential geothermal credit (Section 25D) and the air-source credit (Section 25C) both ended Dec 31, 2025, so 2026 installs don't get a federal credit on either side. Geothermal usually wins the 15-year total in cold climates; air-source usually wins in mild ones.

Your home

Compare a ground-source (geothermal) heat pump to an air-source heat pump on operating cost, upfront cost, payback, and 15-year total.

15-year total cost verdict

Air-source wins the 15-year total by about $11,780 in your inputs.

Geothermal always wins on running cost — by $510/yr at these inputs. Whether that overcomes its higher upfront cost over 15 years depends on your climate, electricity rate, and loop type.

Geothermal's upfront premium of $19,500 pays back in about 37.9 years on operating savings alone.

Annual operating cost

Geothermal

$830/yr

4,900 kWh · heat COP 4.0 / cool COP 5.0 (flat)

Air-source

$1,350/yr

7,929 kWh · heat COP 2.4 (Cold) / cool COP 4.2

Upfront installed cost

Air-source

$10,500

No federal credit on 2026 installs

Geothermal

$30,000

standard loop · no federal credit on 2026 installs

Geothermal premium over air-source: $19,500.

15-year total cost (upfront + operating)

Geothermal

$42,500

$30,000 upfront + 15 × $830/yr

Air-source

$30,720

$10,500 upfront + 15 × $1,350/yr

Geothermal ground loops typically last 50+ years; air-source outdoor equipment typically lasts about 15 years. A 15-year total cost understates geothermal's longevity advantage.

Practical caveats

  • Geothermal needs land or boreholes. Horizontal loops need yard area you can excavate; vertical loops need professional drilling. Dense urban lots often can't accommodate either economically.
  • Loop life vs equipment life.Ground loops typically last 50+ years; the indoor heat pump unit lasts 20–25 years. Air-source outdoor units typically last about 15 years. Over 30–50 years geothermal's advantage grows well beyond the 15-year total shown above.
  • No federal credit on 2026 installs. The One Big Beautiful Bill Act (Public Law 119-21, July 4, 2025) terminated both the Section 25C credit (air-source heat pumps) and the Section 25D Residential Clean Energy Credit (residential geothermal) for any system placed in service after Dec 31, 2025. Systems installed by that date can still claim and carry the credit forward. State and utility incentives may still apply to both — check your local programs.

These are ballpark estimates, not contractor quotes. Geothermal cost varies enormously with loop type, soil conditions, drilling, and site access. Federal residential clean-energy credits (Section 25C for air-source, Section 25D for geothermal) ended Dec 31, 2025 under the One Big Beautiful Bill Act — neither system qualifies federally for 2026 installs. If you have a pre-2026 install, consult a tax professional about eligibility and carryforward. Get written quotes from licensed geothermal and HVAC contractors before deciding.

How this calculator works

We estimate annual delivered heating and cooling, divide by each system's seasonal COP to get electricity input, and multiply by your electricity rate. The key difference between systems: geothermal's COP stays flat across climates, while air-source's heating COP drops in the cold.

  • Heat demand (H) = 5.5 kWh/sq ft × home size × heating climate factor (Hot 0.35 to Very Cold 2.30) × insulation factor (Poor 1.30 to Well 0.75).
  • Cooling demand (C) = 2.5 kWh/sq ft × home size × cooling climate factor (Hot 2.50 to Very Cold 0.25) × insulation factor.
  • Geothermal energy use = H ÷ 4.0 + C ÷ 5.0. Geothermal COP stays flat because ground temperatures below the frost line stay near 50–55°F year-round.
  • Air-source energy use = H ÷ air heating COP + C ÷ 4.2. Air-source heating COP varies by climate: Hot 3.2, Warm 3.0, Mixed 2.7, Cold 2.4, Very Cold 2.1. Cooling COP is 4.2 (flat).
  • Upfront cost. Air-source: $4,500 fixed + $3.00/sq ft. Geothermal: ($12,000 fixed + $9.00/sq ft) × loop factor (Horizontal 0.85, Standard 1.00, Vertical 1.15). The former 30% Section 25D credit expired Dec 31, 2025 and is OFF by default; turn it on only if your system was placed in service by that date, in which case it cuts the geothermal upfront by 30%. Air-source has no federal credit either way for 2026 installs.
  • Simple payback= geothermal's upfront premium ÷ annual operating savings. Shown only when both are positive. Ignores future rate changes and state/utility incentives.
  • 15-year total= upfront + 15 × operating cost for each. Geothermal ground loops last 50+ years; air-source outdoor equipment about 15 years — a longevity advantage that isn't reflected here.

Frequently asked questions

Is a geothermal heat pump worth it?
It depends on your climate and how long you plan to stay in the home. In Cold and Very Cold US climates, geothermal usually wins the 15-year total cost despite its higher upfront — air-source efficiency drops sharply in the cold, while geothermal's COP stays flat. In Hot, Warm, and Mixed climates, air-source typically wins the 15-year total because the operating-cost gap is smaller and can't overcome the geothermal premium. Geothermal ground loops last 50+ years, so if you're staying long-term the math gets better.
How much more does geothermal cost than air-source?
A geothermal heat pump system typically costs $25,000 to $45,000 installed, vs roughly $10,000 to $16,000 for an air-source system. The ground loop — horizontal trenching or vertical boreholes — is the main extra cost. For 2026 installs there is no federal credit on either system (Sections 25C and 25D both expired Dec 31, 2025), so geothermal's net premium over air-source is typically $15,000 to $25,000 for a typical home. State and utility rebates may reduce that.
What is geothermal's payback period?
Simple payback on geothermal's upfront premium is typically 10 to 15 years in Cold and Very Cold climates with high electricity prices, and 20+ years in Hot, Warm, and Mixed climates. The cooler your climate and the higher your electricity rates, the faster geothermal pays back — because that's where air-source operating cost is highest. With the federal 25D credit gone for 2026 installs, paybacks are longer than they were under the prior law; state and utility rebates can shorten them where available.
Does geothermal still get the 30% federal tax credit?
No, not for 2026 installs. The One Big Beautiful Bill Act (Public Law 119-21, signed July 4, 2025) terminated the Section 25D Residential Clean Energy Credit (residential geothermal) and the Section 25C credit (air-source heat pumps) for any system placed in service after Dec 31, 2025. Systems placed in service by that date can still claim the credit on their 2025 return and carry forward any unused portion. State and utility incentives may still apply — check your local programs. Neither system gets a federal credit going forward.
How long do geothermal ground loops last?
Geothermal ground loops typically last 50 years or more — they're inert plastic piping buried below the frost line, with nothing to wear out. The indoor heat pump unit lasts 20 to 25 years, longer than air-source equipment, because it's not exposed to weather. Air-source outdoor units typically last about 15 years. Over 30 to 50 years of ownership, geothermal's longevity advantage is substantial and isn't captured by a 15-year total cost.
Why is geothermal better in cold climates?
Air-source heat pump efficiency falls as outdoor air gets colder — heating COP drops from about 3.2 in Hot climates to about 2.1 in Very Cold climates. Geothermal heat pumps draw heat from the ground at 50–55°F year-round (below the frost line), so their heating COP stays flat at about 4.0 regardless of climate. The colder it gets above ground, the bigger geothermal's efficiency advantage — which is exactly when heating demand is highest.

Disclaimer: These are estimates for budgeting, not contractor quotes. Geothermal installed cost varies enormously with loop type, soil conditions, drilling, and site access. Federal residential clean-energy credits (Section 25C for air-source, Section 25D for geothermal) ended Dec 31, 2025 under the One Big Beautiful Bill Act — neither system qualifies federally for 2026 installs. If your system was placed in service by Dec 31, 2025, consult a tax professional about claiming the credit on your 2025 return and carrying forward any unused portion. State and utility incentives may still apply to both. Get written quotes from licensed geothermal and HVAC contractors before deciding. HeatPumpLab is independently operated and not affiliated with any installer network.