What Is a Heat Pump?

If you’re comparing heating and cooling options for your home, the term “heat pump” probably keeps coming up — and for good reason. A heat pump is a single system that both heats and cools your house by moving heat rather than generating it, which is why it can cut energy use by 30% to 60% compared with electric resistance heating. This guide explains how heat pumps work, the major types available in the US, what sizing specs like BTU and HSPF2 actually mean, and what installation realistically costs in 2026.

Key Takeaways

• A heat pump moves heat instead of burning fuel, so it delivers 2 to 4 units of heat for every unit of electricity it consumes.
• One system handles both heating and cooling, replacing the traditional furnace-plus-AC pair.
• Typical installed cost in the US is $5,500 to $12,000 for a ducted air-source system, with tax credits covering up to $2,000.
• Cold-climate models now perform reliably below 5°F, making them viable across most of the country.

How a Heat Pump Works

Every heat pump — whether it heats your home or cools it — runs the same basic refrigeration cycle. The only thing that changes is the direction the refrigerant flows.

Cooling Mode

In summer, the heat pump behaves exactly like a central air conditioner:

1. The indoor coil absorbs heat and humidity from your return air.
2. The compressor pressurizes refrigerant, raising its temperature.
3. The outdoor coil releases that heat into the outside air.
4. Cooled, dehumidified air is pushed back through your ductwork.

Heating Mode

In winter, a reversing valve flips the refrigerant path:

1. The outdoor coil now acts as an evaporator, absorbing whatever heat exists in the outside air — even at 20°F, outdoor air still contains usable thermal energy.
2. The compressor raises the refrigerant to a high temperature.
3. The indoor coil releases that heat into your ductwork and living space.

This is the key distinction from a furnace: nothing is combusted. The heat is transferred, not created. In practical terms, an air-source heat pump in mild weather operates at a COP (coefficient of performance) of 3 to 4, meaning every dollar of electricity produces three to four dollars’ worth of heat. At 17°F, expect a COP closer to 1.5 to 2.0 — still more efficient than electric baseboard heat, which tops out at 1.0.

The Component Short List

If you’re new to the terminology, this HVAC definition guide covers the core industry language, and it helps to know how the rest of your equipment fits together before you shop.

Heat Pump vs. Furnace vs. Air Conditioner

The bottom line: a heat pump replaces two appliances with one and typically costs less to install than a new furnace plus a new air conditioner. The trade-offs are a shorter service life, a higher repair cost profile, and heating performance that depends on your local design temperature.

Types of Heat Pumps

Air-Source Heat Pumps

The most common type in the US. A split system with an outdoor unit and an indoor air handler connected to your existing ductwork. Standard models are rated for operation down to roughly 17°F to 25°F before relying on backup heat. Installed cost: $5,500 to $12,000, including ductwork modifications if needed.

Cold-Climate Air-Source Heat Pumps (ccASHP)

Specifically engineered for northern climates, these units maintain rated capacity at 5°F and continue running to about -13°F. They use vapor injection compressors and larger coils. Expect to pay a $1,000 to $2,500 premium over standard models, though utility rebates often offset it. If you live in USDA Zones 5–7, this is the category to shop.

Ductless Mini-Split Heat Pumps

No ductwork required. A wall-mounted indoor head pairs with an outdoor unit, making these ideal for additions, garages, finished basements, and older homes without ducts. Cost runs $3,000 to $6,500 for the first zone and $1,500 to $3,000 per additional zone.

Geothermal (Ground-Source) Heat Pumps

The most efficient option available, using stable ground temperatures (50°F–70°F) instead of outdoor air. Geothermal systems achieve COPs of 3.5 to 5.0 year-round, but the ground loop is expensive: $15,000 to $35,000 installed for a typical home. A 30% uncapped federal tax credit through 2032 changes the math considerably.

Heat Pump Water Heaters

A related category worth mentioning: these use the same principle to heat domestic hot water at roughly 2 to 3 times the efficiency of a standard electric tank. Installed cost is $1,200 to $3,500, with a 30% federal credit up to $2,000.

Reading Heat Pump Specs: BTU, SEER2, and HSPF2

You’ll see a wall of numbers on any spec sheet. Here’s what matters.

BTU and Tonnage

BTU (British thermal units) measure heating and cooling capacity. One “ton” of capacity equals 12,000 BTU per hour. As a rough starting point:

• 20 BTU per square foot of conditioned space in moderate climates
• 30 to 45 BTU per square foot in cold climates or poorly insulated homes

A 2,000 sq. ft. home in a mixed climate lands around 36,000 to 48,000 BTU, or a 3- to 4-ton system. Do not size from square footage alone — insist on a Manual J load calculation that accounts for window area, insulation levels, air leakage, and duct losses. Oversized heat pumps short-cycle, dehumidify poorly, and wear out faster.

SEER2

SEER2 measures cooling efficiency. The federal minimum for split-system heat pumps is 14.3 SEER2 in most regions. ENERGY STAR certified units generally hit at least 15.2 SEER2, and “Most Efficient” models exceed 18.

HSPF2

HSPF2 measures heating efficiency across the season — the number that actually matters if you’re buying this system to stay warm. The federal minimum is 7.5 HSPF2 for split systems, and ENERGY STAR requires at least 8.1. Higher is better; premium cold-climate units reach 10 or above.

Refrigerant Note for 2026

As of January 1, 2025, newly manufactured residential systems must use refrigerants with a global warming potential of 700 or lower. That means R-454B or R-32 have replaced R-410A. If a contractor quotes you leftover R-410A equipment at a steep discount, factor in long-term refrigerant availability before saying yes.

How Much Does a Heat Pump Cost?

Incentives That Change the Numbers

• Federal 25C tax credit: 30% of project cost, up to $2,000 per year for air-source heat pumps and heat pump water heaters, through 2032.
• Geothermal credit: 30% of total cost with no dollar cap.
• State and utility rebates: frequently $500 to $4,000, with low- and moderate-income households eligible for larger amounts under HEEHRA programs.
• ENERGY STAR labeling: a useful shorthand — certified units are guaranteed to meet the efficiency threshold most rebate programs require.

Always confirm current program details with your state energy office and your utility before signing a contract. Rebate rules change annually, and the incentives frequently cover the entire cost gap between a standard and high-efficiency unit.

Troubleshooting: When Something Seems Wrong

Heat pumps fail in predictable ways. These symptoms are worth a service call:

• System blows cold air in heating mode — reversing valve, reversing valve solenoid, or low refrigerant charge.
• Frequent defrost cycles — normal in cold, damp weather, but excessive cycling points to a bad defrost board or sensor.
• Auxiliary heat runs constantly — the heat pump may be undersized, low on charge, or the balance point is set incorrectly on the thermostat.
• Ice buildup on the outdoor unit — a defrost failure. Never chip ice off the coil; call a technician.
• Short cycling — often an oversized system, a failing capacitor, or a thermostat wired for the wrong equipment type.
• Rattling or screeching outdoors — loose fan blades, failing bearings, or debris in the unit.

Simple homeowner checks first: replace the air filter every 1 to 3 months, verify the thermostat is set to HEAT (not AUX/EMERGENCY), confirm the outdoor unit has 2 feet of clear space, and check that the breaker and service switch are on.

Maintenance and Lifespan

Plan on two professional visits per year — one in spring before cooling season, one in fall before heating season. A proper tune-up includes refrigerant charge verification, coil cleaning, electrical connection tightening, condensate drain clearing, defrost control testing, and airflow measurement. Budget $150 to $300 annually, which is far cheaper than the $1,200 to $2,500 compressor replacement it helps you avoid.

Homeowner tasks between visits: change filters on schedule, keep the outdoor unit clear of leaves and snow, hose off the outdoor coil each spring, and don’t block supply or return registers with furniture.

With this routine, an air-source heat pump should reach 12 to 15 years, and geothermal indoor equipment can last 20 to 25 years.

Is a Heat Pump Right for Your Home?

A heat pump is a strong fit if you answer yes to most of these:

• You’re replacing both a furnace and an air conditioner, or your AC is 12+ years old.
• You have ducted central air already, or your home suits a ductless layout.
• Your electricity rate is below roughly $0.20/kWh, or you have solar.
• You live in a climate where winter design temperatures stay above -13°F (which covers nearly all of the contiguous US with cold-climate equipment).
• You want to reduce on-site fossil fuel use or qualify for electrification rebates.

It may be a weaker fit if you have very cheap natural gas, extremely high electric rates with no solar, or a house with ductwork that needs $10,000+ in sealing and repair. When in doubt, get a Manual J load calculation and a written quote from at least three licensed contractors — and read our full heat pump installation guide before you book an appointment.

Frequently Asked Questions

Do heat pumps actually work in freezing weather? Yes. Modern cold-climate heat pumps are rated to deliver full heating capacity at 5°F and can continue operating down to about -13°F. Below the system’s balance point, they pair with electric resistance strips or a gas furnace as backup heat. Older single-stage units from the 2000s are a different story — those typically struggle below 25°F.

How long does a heat pump last? A well-maintained air-source heat pump typically lasts 12 to 15 years, and geothermal indoor equipment can reach 20 to 25 years. Annual professional maintenance is the single biggest factor in reaching that upper range — neglected systems often fail around year 10.

Is a heat pump cheaper to run than a furnace or AC? In most US markets, yes. A heat pump costs far less to run than electric resistance heat and is typically competitive with or cheaper than propane, oil, and — in many regions — natural gas. Actual savings depend on your electricity rate, local climate, and how well the system is sized, sealed, and commissioned.

Conclusion

A heat pump is a single, reversible refrigeration system that heats and cools your home by moving thermal energy instead of burning fuel — and that one design choice is why it can deliver two to four times more heat per dollar than electric resistance heating. For most US homeowners replacing an aging furnace-and-AC pair, a properly sized ducted air-source unit in the $5,500 to $12,000 range, backed by a $2,000 federal tax credit and utility rebates, is the most cost-effective path to year-round comfort. Cold-climate models have erased the old “heat pumps don’t work up north” objection, and the 2025 refrigerant transition means new equipment is both more efficient and lower-impact than what it replaces.

The single most important step isn’t picking a brand — it’s insisting on a Manual J load calculation and a contractor who commissions the system rather than just dropping it in. Get three written quotes, verify the SEER2 and HSPF2 ratings against ENERGY STAR thresholds, confirm which rebates you qualify for before signing, and keep up with twice-yearly maintenance. Do that, and a heat pump will comfortably carry your home through both the hottest and coldest weeks of the year for well over a decade. For related terms as you continue your research, browse the rest of our HVAC glossary.