The break-even map — when geothermal makes sense

Geothermal always wins on operating cost. Whether it wins on 15-year total cost depends on two things: how cold your climate is, and how expensive your electricity is. Here is the 15-year TCO gap for a 2,000 sq ft home with average insulation and a standard horizontal loop, at each climate × regional-electricity intersection. Positive = geothermal wins.

The pattern: geothermal wins the 15-year total in Cold and Very Cold climates, especially with expensive electricity (Northeast). It loses in Hot and Warm climates where heating demand is minor and the geothermal upfront premium never pays back. On a 30-year window (which better matches the 50+ year loop lifespan) every cell shifts ~$15k–$25k in geothermal's favor.

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.