Ground Source Heat Pump (GSHP)
A ground source heat pump (GSHP) — also called a geothermal heat pump in everyday North American usage — is one of the most efficient heating and cooling systems available for residential homes in the United States. Rather than generating heat by burning fuel or rejecting heat into hot summer air, a GSHP moves thermal energy between your home and the earth. Per the U.S. Department of Energy, soil below the frost line stays roughly 50°F to 60°F year-round, and that stable temperature is the reason ground source systems can cut heating energy use by 30% to 70% and cooling energy use by 20% to 50% versus conventional equipment, depending on climate zone and the fuel being displaced (DOE EERE, Geothermal Heat Pumps; EPA, Geothermal Heating & Cooling Technologies).
This page is the terminology and technology hub. If you arrived searching for "ground source heat pump," "GSHP," "geothermal heat pump," or "GeoExchange," the answer is that all four phrases describe the same residential technology. The federal incentive landscape shifted significantly in 2025, so this guide also covers what changed, what still applies, and how the system is sized, installed, and operated today.
Ground Source Heat Pump vs Geothermal Heat Pump vs GeoExchange: Terminology
The same equipment is sold under several names depending on who is talking to whom. The labels are not interchangeable in every context, but they refer to the same underlying technology.
- Ground Source Heat Pump (GSHP) — the technical and international term used by engineering bodies including ASHRAE in its handbooks and standards, and by the International Ground Source Heat Pump Association (IGSHPA). When you read peer-reviewed papers, ANSI/CSA/IGSHPA accreditation specs, or international literature, "GSHP" is the convention.
- Geothermal heat pump — the common North American consumer term, also used by the U.S. Department of Energy and the U.S. Environmental Protection Agency in homeowner-facing literature. Linguistically it is slightly imprecise (true "geothermal" power generation taps deep volcanic heat, while a residential heat pump simply uses near-surface ground temperature as a thermal reservoir), but the term has been standard in U.S. consumer use for several decades and is unlikely to change.
- GeoExchange — a registered term coined and promoted by the Geothermal Heat Pump Consortium beginning in the 1990s. It refers to the same closed-loop or open-loop ground-coupled heat pump technology, marketed under the GeoExchange brand for industry awareness.
- Earth-coupled heat pump and water-source heat pump — older or specialized variants of the same family. A pure water-source heat pump uses a building-loop or surface-water source rather than a buried earth loop, but the heat exchange principle is identical.
Throughout this guide we use "GSHP" and "geothermal heat pump" interchangeably to match how the industry, federal agencies, and homeowners actually speak.
How a Ground Source Heat Pump Works
A GSHP is a vapor-compression heat pump — the same thermodynamic cycle as a refrigerator or an air conditioner — coupled to a buried piping loop instead of an outdoor coil. Three subsystems work together:
- The ground loop — high-density polyethylene (HDPE) pipe buried in the earth that circulates a heat-transfer fluid, typically water with a propylene-glycol antifreeze. The loop exchanges heat with surrounding soil, rock, or groundwater.
- The heat pump unit — the indoor cabinet containing the compressor, refrigerant circuit, water-to-refrigerant heat exchanger (the loop side), and refrigerant-to-air or refrigerant-to-water heat exchanger (the home side).
- The distribution system — ductwork, hydronic baseboards, or radiant floors that deliver conditioned air or water to the home.
In heating mode, the loop fluid (warmer than the boiling point of the refrigerant under low pressure) gives up heat to the refrigerant in the loop heat exchanger. The compressor then raises that refrigerant to a higher temperature, and the indoor heat exchanger releases the heat into your home. In cooling mode, the refrigerant cycle reverses: the home-side coil absorbs heat from indoor air, and the loop heat exchanger rejects that heat into the cool ground.
Because soil at typical loop depth is roughly 50–60°F year-round (DOE EERE), the temperature difference the compressor must bridge is far smaller than what an air source heat pump faces on a 5°F winter morning or a 95°F summer afternoon. That smaller "lift" is why GSHPs operate at a Coefficient of Performance (COP) of 3 to 5 in heating and an Energy Efficiency Ratio (EER) of 14 to 30 in cooling, well above what air source equipment can deliver in extreme weather.
Refrigerant Transition: R-454B (Puron Advance)
Under the U.S. EPA's American Innovation and Manufacturing (AIM) Act, the residential heat pump industry is transitioning away from R-410A to lower-global-warming-potential refrigerants, primarily R-454B (marketed by Carrier as Puron Advance) and R-32 (EPA AIM Act & HFC Phasedown). Carrier modernized its residential GSHP line in June 2025 with R-454B, NFC-enabled commissioning, and InteliSense diagnostics. If you are quoted equipment in 2026 still on R-410A, ask the contractor how that affects future service availability and refrigerant cost over the 20–25-year life of the indoor unit.
Ground Loop Configurations
The U.S. Department of Energy recognizes four primary ground loop types. Choice depends on land area, soil and rock conditions, water availability, and budget.
1. Vertical Closed-Loop
U-bend HDPE pipe is inserted into boreholes typically 150 to 400 feet deep, then grouted with a thermally conductive grout. A typical 3-ton home requires multiple boreholes spaced roughly 15–20 feet apart. Vertical loops use minimal land area and perform well in dense soil or bedrock, but drilling is the most expensive part of the system. In states such as Indiana, vertical geothermal boreholes are regulated as wells under 312 IAC 13-8-1, requiring a licensed driller; many other states have similar requirements.
2. Horizontal Closed-Loop
Pipe is laid in trenches typically 4 to 6 feet deep across an open area of yard. A standard residential loop uses 300 to 600 linear feet of pipe per ton of capacity, depending on soil thermal conductivity and design parameters. Horizontal loops are the cheapest option when adequate land is available, but they require significant uncovered yard area and disturb landscaping during installation.
3. Pond/Lake Closed-Loop
If a sufficiently deep, year-round pond or lake (generally at least 8 feet deep at its lowest level and at least half an acre in surface area) sits on or near the property, coiled pipe can be sunk to the bottom and anchored. Pond loops are typically the lowest-cost option where they are feasible because no excavation is needed, but they require a suitable water body and local environmental permits.
4. Open-Loop (Standing Column or Pump-and-Dump)
An open-loop system draws groundwater from a well, runs it through the heat pump's water-side heat exchanger, and discharges it to a return well, surface water, or storm drain (subject to state and local rules). Open loops can deliver excellent efficiency because groundwater is already at the deep stable temperature, but they require adequate aquifer yield, water chemistry suitable for the heat exchanger, and a permitted discharge path. Many jurisdictions restrict or prohibit open-loop systems near sensitive aquifers.
Use our ground loop sizing calculator for a first-pass estimate of which loop type fits your site.
Efficiency Metrics: COP, EER, HSPF
Three numbers describe GSHP efficiency:
- COP (Coefficient of Performance) — heating efficiency. A COP of 4 means the unit delivers 4 units of heat to the home for every 1 unit of electricity consumed. ENERGY STAR-certified residential GSHPs typically post heating COPs of 3.6 to 5.0 (ENERGY STAR, Geothermal Heat Pumps).
- EER (Energy Efficiency Ratio) — cooling efficiency at standard rating conditions. ENERGY STAR closed-loop GSHPs commonly rate at EER 17 to 30. By comparison, a high-efficiency air conditioner is typically EER 12 to 14.
- HSPF (Heating Seasonal Performance Factor) — used for air source heat pumps, not strictly applicable to GSHPs (which are rated by COP because their source temperature is stable rather than seasonal).
Real-world performance closely matches lab ratings for ground source systems. A 2025 field study of more than 1,000 installed heat pumps found GSHPs missed their expected efficiency by only 2% on average, compared with 17% for air source heat pumps — the gap reflects the fact that GSHPs draw from a stable thermal reservoir, while ASHPs are penalized when outdoor air is hot or cold.
Installation Cost (2026 National Averages)
Per RSMeans cost data and contractor surveys, the 2026 U.S. average installed cost for a 3-ton residential GSHP system is approximately $25,500, with a typical range of $20,000 to $27,000 for properties in standard soil. New England granite, complex bedrock, or hard-to-access lots can push the total to $35,000 to $50,000+. Per-ton averages run roughly $8,500/ton, with a national range of $4,500 to $12,500+.
Drilling and trenching account for 50% to 70% of total project cost on vertical-loop installations. Specialized labor wage inflation has driven installed costs up more than 4% year over year for three consecutive years through 2026, per RSMeans.
| Cost Component | Typical Share | Notes |
|---|---|---|
| Ground loop (drilling/trenching + pipe + grout) | 50–70% (vertical), 30–45% (horizontal) | Largest single line item; depends on soil/rock |
| Heat pump unit + indoor mechanical | 15–25% | Variable-capacity models cost more |
| Distribution (ductwork, hydronic, controls) | 10–20% | Higher in retrofit with no existing duct |
| Permits, design, commissioning | 3–8% | Includes loop design and load calculation |
For a regional and home-size-specific estimate, see geothermal heat pump cost.
Federal Incentives in 2026: What Changed
The federal incentive landscape for residential geothermal shifted significantly with the One Big Beautiful Bill Act (P.L. 119-21), signed July 4, 2025 (congress.gov, P.L. 119-21). Three programs are most relevant:
§25D Residential Clean Energy Credit — Terminated for 2026+ Installs
The 30% federal tax credit for residential geothermal expenditures, previously scheduled under the Inflation Reduction Act to run through 2032, was terminated for new expenditures made after December 31, 2025. Per IRS guidance, "expenditure made" means the date the system is installed — not the contract date or deposit date. Homeowners with unused 2025 credits can still carry the credit forward on Form 5695 (IRS Form 5695, Residential Energy Credits). For installs completed in 2026 and later, the §25D credit no longer applies.
§48 Commercial Investment Tax Credit — Still Active
The §48 commercial ITC for business-owned geothermal systems remains active. Base credit is 6%, rising up to 30% with domestic-content, prevailing-wage, energy-community, or apprenticeship bonuses, and phasing down to 5.2% in 2033, 4.4% in 2034, and 0% after December 31, 2034 (IRS, Energy Investment Tax Credit). Wind and solar were phased out under OBBBA more aggressively, but geothermal was explicitly preserved.
Third-Party Ownership (TPO) Leasing — A Path to §48 Savings for Homeowners
Because §48 still applies to business-owned systems, a corporate lessor can install and own the GSHP, claim the §48 ITC, and pass the value through to the homeowner via reduced lease payments. TPO geothermal leasing is growing in 2026 as a workaround for the §25D termination, and several specialty financiers are building out residential lease products. Compare lease economics carefully against ownership-plus-state-incentive scenarios.
HEEHRA / HEAR (§50122) — Heat Pump Rebate
The High-Efficiency Electric Home Rebate Act (now administered as HEAR) provides up to $8,000 per household for a heat pump including GSHPs, income-tiered: full rebate at less than 80% of Area Median Income, 50% rebate at 80–150% AMI. Programs are state-administered, and rollouts vary; check your state energy office for current status.
What's Dead
The FHA PowerSaver pilot is dead — the program ended in 2015 and HUD archived obsolete guidance under 85 FR 69640 (Nov 3, 2020). Marketing copy that still references PowerSaver is stale. Modern GSE financing paths are Fannie Mae HomeStyle Refresh (effective March 31, 2026, SFC 892 — a rebrand of HomeStyle Energy with broader scope including energy and resiliency upgrades up to 15% of future home value) and Freddie Mac GreenCHOICE Mortgage.
State Incentives (Selected Programs)
State and utility incentives are now the primary remaining stack for residential GSHP buyers. Programs change annually; verify current rules with the state agency or utility before signing a contract.
- New York — State tax credit of 25% of installed cost, capped at $10,000 per primary residence (cap raised from $5,000 effective July 1, 2025 per S4882). Source: tax.ny.gov. NYS Clean Heat / NYSERDA utility-administered rebates ($7K–$9K average) are separate.
- Massachusetts — Mass Save whole-home GSHP rebate of $13,500 in 2026 (down from $15,000 in 2025); $25,000 income-qualified rebate at ≤60% State Median Income. The Mass Save HEAT Loan is a separate 0% APR financing product, not a rebate.
- Connecticut — Smart-E Heat Pump Special at 0.99% APR through June 30, 2026 (the standard Smart-E rate is 6.99–7.99%). Source: ctgreenbank.com.
- Indiana — Note that the property tax deduction for geothermal under former IC 6-1.1-12-34 was repealed by SEA 1 (2025), retroactive to January 1, 2025; it now applies only to assessment dates before that date. Vertical closed-loop drilling requires a licensed driller per IC 25-39 and 312 IAC 13-8-1.
- Maryland, Virginia, Washington — property tax exemption (MD), sales tax exemption (VA, WA). Verify current scope with the state department of revenue.
For state-by-state detail, see geothermal rebates by state.
Realistic Payback and Annual Savings
Per DOE/EERE modeling and Monte Carlo analyses, realistic residential GSHP payback ranges are 5–10 years overall, with a 7.5-year median when replacing an air source heat pump and a 9.2-year median when replacing a gas furnace plus AC. Without §25D for 2026+ installs, expect 10–15 years unincentivized, or 7–12 years with state rebates.
Per EPA, expected energy savings depend strongly on the fuel being displaced and the climate zone:
| Displaced Fuel | Heating Cost Savings (EPA range) | Cooling Cost Savings | Notes |
|---|---|---|---|
| Electric resistance | 50–70% | 20–50% | Highest savings band; common in retrofit |
| Heating oil / propane | 40–60% | 20–50% | High savings, especially in Northeast |
| Older (80% AFUE) gas furnace | 30–50% | 20–50% | Solid economics in cold climates |
| Modern (95–97% AFUE) gas furnace | 20–35% | 20–50% | Lowest heating-side savings; cooling still strong |
Note that the often-quoted "60% energy savings" is a midpoint of this range, not a flat number that applies to every household. Actual savings depend on your displaced fuel, your climate zone, your home's envelope, and your local electricity and fuel rates.
Equipment Lifespan
Indoor heat pump units typically operate 20–25 years, comparable to or longer than air source heat pumps. The ground loop is rated for 50+ years by HDPE pipe manufacturers and IGSHPA design guidance. When the indoor unit is eventually replaced, the existing ground loop is typically reused, which substantially lowers the cost of the second-generation system.
Home Value Impact
Per NAHB, Lawrence Berkeley National Laboratory, and Zillow data, a residential geothermal system typically increases home value by $8,700 to $15,000. Higher figures up to $20,000 have been documented in luxury or oil-displacement markets, but those are not typical for the median U.S. residence. Treat home-value uplift as a meaningful component of total ROI but not the primary purchase justification — the operating-cost savings and equipment lifespan dominate the financial case.
Comparison: Ground Source vs Air Source vs Conventional
The simplest way to think about a GSHP is as the upper end of the heat-pump performance curve, where extra capital cost buys higher and more stable seasonal efficiency.
| System | Heating Efficiency | Cooling Efficiency | Installed Cost (3-ton) | Cold-Weather Performance |
|---|---|---|---|---|
| Ground source heat pump (GSHP) | COP 3.5–5.0 | EER 17–30 | $20,000–$27,000+ | Stable; loop temperature does not drop with outdoor air |
| Modern cold-climate air source heat pump (ASHP) | COP 2.0–3.5 (drops in cold) | EER 12–18 | $8,000–$15,000 | Capacity falls below 5°F; resistance backup may engage |
| 95% AFUE gas furnace + AC | 0.95 effective | EER 12–14 | $6,000–$10,000 | N/A (combustion) |
| Electric resistance + AC | 1.0 (100%) | EER 12–14 | $5,000–$8,000 | Consistent but expensive to operate |
For a deeper side-by-side, see geothermal vs air source heat pumps.
Selecting a Contractor
System performance lives or dies on loop design and proper sizing. The contractor should:
- Hold IGSHPA accreditation for ground loop installation (igshpa.org) — and in many states, hold a separate well-driller license for vertical boreholes.
- Perform a Manual J load calculation on the home, not size by square footage rule of thumb.
- Run a Manual S equipment selection matched to the load.
- Provide a ground loop design based on local soil thermal conductivity (TC test recommended for jobs over 5 tons).
- Be licensed and insured under your state's HVAC contractor or mechanical license.
- Offer at least a 10-year manufacturer warranty on the heat pump and ideally a 50-year warranty on the loop.
Use our directory to find an IGSHPA-accredited geothermal contractor. We list verified installers across all 50 U.S. states.
Maintenance
GSHPs require less maintenance than fossil-fuel systems because there is no combustion, no flue, and no outdoor coil exposed to weather. Recommended schedule:
- Monthly — replace or clean the indoor air filter (1-inch filters monthly; 4–5-inch media filters every 6–12 months).
- Annually — qualified technician inspection of refrigerant charge, loop pressure, antifreeze concentration, and electrical connections.
- Every 5 years — comprehensive performance check including loop heat-exchanger cleaning and compressor diagnostics.
- Loop — typically no maintenance for the life of the loop, beyond monitoring loop pressure during the annual inspection.
For more, see geothermal heat pump maintenance.
Climate Zone Considerations
GSHP performance is more uniform across climate zones than air source equipment because the ground temperature varies less than air temperature. That said, the economic case is shaped by what fuel the system displaces:
- Cold climates (Minnesota, Wisconsin, Northern New York, New England, Montana) — strongest economic case when displacing oil, propane, or electric resistance heat. Loop design must account for longer heating runs and may favor vertical configurations to maintain loop temperature through winter.
- Moderate climates (Ohio, Pennsylvania, Mid-Atlantic, Pacific Northwest interior) — solid case versus gas; cooling-side savings add value.
- Mild climates (Carolinas, Tennessee, Georgia) — heating savings are smaller but cooling savings are substantial; payback is typically longer than in cold climates.
- Hot climates (Texas, Florida, Arizona) — cooling-dominated math. The compressor rejects heat into 60–75°F ground rather than 95°F+ air, and EER advantages are pronounced. Open-loop systems are common where groundwater rules permit.
Frequently Asked Questions
Q: What is the difference between a ground source heat pump, a geothermal heat pump, and GeoExchange?
A: They refer to the same technology. Ground source heat pump (GSHP) is the international and technical term used by ASHRAE and IGSHPA. Geothermal heat pump is the common North American consumer term used by the U.S. Department of Energy and EPA in homeowner-facing literature. GeoExchange is a registered marketing term coined by the Geothermal Heat Pump Consortium for the same technology.
Q: How efficient are ground source heat pumps?
A: Per EPA, a properly designed GSHP saves 30–70% on heating costs and 20–50% on cooling costs versus conventional systems, with actual savings depending on climate zone and the fuel being displaced. Typical heating COP is 3 to 5 and cooling EER is 14 to 30. A 2025 field study of more than 1,000 installed heat pumps found GSHPs missed expected efficiency by only 2% on average, compared with 17% for air source heat pumps.
Q: Will a ground source heat pump work in my climate?
A: Yes. GSHPs are installed and operating in all 50 U.S. states. Cold climates produce the strongest savings versus oil, propane, and resistance heat; mild climates produce slightly lower heating savings but strong cooling savings. The decisive factors are the fuel you are displacing and your local electricity rate, not climate zone alone.
Q: How much land do I need for a horizontal closed loop?
A: A typical 3-ton residential horizontal loop uses 300–600 linear feet of pipe per ton of capacity, occupying roughly 4,000–6,000 square feet of yard depending on trench layout. Roughly a quarter to half acre of usable lawn is typically sufficient. If land is constrained, vertical or pond loops are alternatives.
Q: How long does a ground source heat pump last?
A: The indoor heat pump unit typically operates 20–25 years. The buried ground loop is rated for 50+ years and is normally reused when the indoor unit is replaced, which lowers the cost of the second-generation system substantially.
Q: Does the federal residential geothermal tax credit still exist for 2026 installs?
A: No. The §25D Residential Clean Energy Credit was terminated for new geothermal expenditures made after December 31, 2025 by the One Big Beautiful Bill Act (P.L. 119-21, signed July 4, 2025). Carryforward of unused 2025 credits via IRS Form 5695 still works. Business-owned systems still qualify for the §48 Commercial Investment Tax Credit, and Third-Party Ownership leasing structures pass §48 savings through to homeowners via reduced lease payments. State and utility programs (NY $10K cap, MA Mass Save $13,500, CT 0.99% Smart-E, etc.) remain the primary direct-incentive stack for 2026.
Q: Are FHA PowerSaver loans still available for geothermal?
A: No. The FHA PowerSaver pilot ended in 2015, and HUD archived the obsolete guidance under 85 FR 69640 in November 2020. Modern GSE financing paths are Fannie Mae HomeStyle Refresh (effective March 31, 2026) and Freddie Mac GreenCHOICE Mortgage.
Q: Can a geothermal heat pump heat my domestic hot water?
A: Many GSHPs include an optional desuperheater, a small heat exchanger that captures rejected heat from the refrigerant cycle and preheats water in the domestic hot water tank. During cooling season the desuperheater can deliver effectively free hot water as a byproduct. It does not replace the water heater on its own but can offset 20–60% of water-heating energy depending on usage patterns.
Q: What refrigerant do new ground source heat pumps use?
A: New residential GSHPs are transitioning to lower-global-warming-potential refrigerants under the EPA AIM Act, primarily R-454B (Carrier markets it as Puron Advance) and R-32. Carrier modernized its residential geothermal line with R-454B in June 2025. If you are quoted equipment still on R-410A, ask the contractor about service availability and refrigerant cost over the 20–25-year service life of the unit.
Q: What happens if my ground loop develops a leak?
A: Leaks in HDPE ground loops are uncommon — the pipe is heat-fused at joints rather than glued or threaded, and there are no joints below grade in a properly installed loop. If the loop loses pressure, a contractor pressure-tests the system to locate the leak (usually at an indoor manifold or near a building penetration), repairs it with a new fusion joint, and recharges the loop fluid. Loop fluid is typically water plus a propylene-glycol antifreeze; it is not a refrigerant and does not require EPA recovery procedures.
Q: Are open-loop systems allowed everywhere?
A: No. Open-loop systems require sufficient groundwater yield, suitable water chemistry, and a permitted discharge path (return well, surface water, or storm drain depending on local rules). Many jurisdictions restrict or prohibit open-loop systems near sensitive aquifers, and some require a separate water-rights permit. Closed-loop systems are unrestricted in most places where any GSHP is allowed.
Q: Should I size the system for my heating load or my cooling load?
A: A qualified contractor performs a Manual J load calculation that produces both numbers and sizes the heat pump and loop to the larger of the two, with consideration for which load drives the design — heating in cold climates, cooling in hot climates. Oversizing leads to short-cycling and reduced comfort and efficiency; undersizing leaves comfort gaps. Variable-capacity GSHPs tolerate sizing imperfection better than single-stage units because they modulate output to match actual load.
Next Steps
If a ground source heat pump is on your shortlist, the practical sequence is: confirm site suitability (yard space, soil/rock, water access), get two or three IGSHPA-accredited contractors to perform Manual J load calculations and bid the project, identify the state and utility incentives currently available in your ZIP, and run a payback analysis against your displaced fuel cost. Use our incentive calculator to see what programs apply to your address and our contractor directory to source bids from accredited installers.