What Is a Heat Pump?

A heat pump is a single piece of equipment that both heats and cools a home by moving heat rather than creating it. In summer it pulls heat out of the house and dumps it outside, exactly as an air conditioner does; in winter it runs the same cycle backwards, pulling heat out of the outdoor air and bringing it inside.

That one difference, moving heat instead of burning fossil fuels to make it, is why heat pumps are so efficient. The underlying technology is refrigeration, the same principle your fridge uses, pointed at a whole house. ENERGY STAR notes that an air-source heat pump can deliver up to three times more heat energy to a home than the electrical energy it consumes, something no furnace can do because a furnace is limited by how much energy is in the fuel it burns.

How a Heat Pump Works

1. Refrigerant absorbs heat

A refrigerant circulates through a sealed loop between an outdoor unit and an indoor coil. In heating mode, the refrigerant in the outdoor coil is colder than the outside air, so heat flows into it. There is usable heat in air well below freezing, which is the part most people find counterintuitive.

2. A compressor concentrates that heat

The refrigerant vapor passes through a compressor, which raises its pressure and, with it, its temperature. This is the step that turns diffuse outdoor warmth into air hot enough to heat a room.

3. The indoor coil releases the heat

Hot refrigerant flows to the indoor coil, a blower moves house air across it, and the heat transfers into your home. The refrigerant cools back to a liquid as it gives up that heat.

4. An expansion valve resets the cycle

The liquid refrigerant passes through an expansion valve, drops in pressure and temperature, and returns to the outdoor coil cold enough to absorb heat again.

5. A reversing valve flips it for summer

The one component an air conditioner does not have is a reversing valve. It changes the direction of refrigerant flow, so the coil that released heat indoors in January absorbs it in July. Same equipment, same refrigerant, opposite direction.

Types of Heat Pumps

Ducted air-source heat pump

The most common type. It uses the same supply and return ducts a traditional furnace and central AC would use, so it is the natural swap for a home whose existing HVAC ductwork is in decent condition. Efficiency is rated in SEER2 for cooling and HSPF2 for heating.

Ductless mini-split

An outdoor unit connected to one or more wall-mounted indoor heads by a small refrigerant line set. No ducts required, and each head is controlled separately. This matters in Philadelphia, where a lot of rowhomes have radiators and no duct system at all.

Cold-climate heat pump

A designation rather than a separate technology, though the underlying technologies have improved a great deal in the last decade. ENERGY STAR cold-climate models are third-party tested for heating capacity down to 5°F, which is the specification that matters in a region that sees genuine cold snaps.

Dual-fuel or hybrid system

A heat pump paired with a gas furnace. The heat pump handles the mild majority of the heating season, and the furnace takes over when it gets cold enough that gas is the cheaper fuel. For homes with existing gas service in this region, this is often the most practical configuration.

Geothermal (ground-source) heat pump

Exchanges heat with the ground instead of the air, through buried loops. Very efficient and very stable in winter, but it requires excavation and sits at the top of the cost range.

Pros and Cons

Advantages	Drawbacks
Heating and cooling from one system, so one piece of equipment to install and maintain	Higher upfront cost than a straight furnace and AC swap in most cases
Delivers up to three times more heat energy than the electricity it uses (ENERGY STAR)	Efficiency falls as outdoor temperature drops, so capacity needs checking against local design temperatures
No combustion in the home, so no flue gases, no carbon monoxide risk from the heating system, and lower emissions than any system burning natural gas, propane or oil on site	Runs on electricity, which in Pennsylvania averaged 21.73 cents per kWh and in New Jersey 24.95 cents per kWh in June 2026 (U.S. EIA)
Cuts electricity used for heating by roughly 65% compared with electric resistance heat (U.S. Department of Energy)	Delivers milder supply air than a furnace, which some people read as "not hot enough" at the register
Ductless versions work in homes that have no duct system at all	Ductless heads are visible on the wall, which is a real objection in some rooms and needs choosing carefully

Is a Heat Pump a Good Fit for a Philadelphia or New Jersey Home?

In this climate the honest answer is: often yes, but the configuration matters more than the decision itself. Heat pumps are now the fastest growing segment of the residential HVAC industry in the United States, and the performance available today is not what it was when most of the skepticism formed.

How local housing stock decides the configuration

Philadelphia rowhomes and twins

Philadelphia rowhomes and older twins frequently have no ductwork, or have a duct system that was squeezed into a converted space and cannot carry the airflow a ducted system needs. Ductless mini-splits solve that without opening walls, and they let you condition a third-floor bedroom that has never been comfortable in either season.

Cape Cods and split-levels in New Jersey

Cape Cods and split-levels across South and Central New Jersey have the opposite problem: ducts exist, but they run through unconditioned attics and lose capacity before the air arrives. A heat pump will expose that, the same as a furnace does, so duct sealing and attic insulation belong in the same conversation.

Winter design temperatures here sit in the low teens, which is comfortably within the range a cold-climate rated system is tested for. Heat pumps are often assumed to suit only moderate climates, and that was true of equipment sold twenty years ago rather than of what is on the market now. For homes with gas already on site, a dual-fuel setup often makes the most financial sense, because it uses the heat pump through the long mild shoulder seasons and switches to gas on the coldest days.

Synergy3 Home Solutions has been installing heating and cooling equipment in this housing stock since 2006. Our NATE-certified technicians size systems from a room-by-room load calculation rather than from the size of the old unit, which is what determines whether a heat pump performs the way it should. The goal is a system that carries the house on its own for most of the winter. See Heat Pump Installation for how we approach it.

What a Heat Pump Feels Like Day to Day

This is the part almost nobody explains before installation, and it accounts for most of the complaints in the first winter.

The air at the register is cooler. A furnace delivers air at 120°F and up in short, obvious bursts. A heat pump delivers air in the 90s over much longer cycles. Ninety-degree air is warmer than a room but cooler than your hand, so it can feel like the system is blowing cold even while the house is holding temperature perfectly. The house gets just as warm; it simply gets there differently.

It runs for longer stretches. Long, low-output cycles are how a heat pump is meant to work, and they produce steadier room temperatures and better humidity control than a system that blasts and stops. A heat pump that short-cycles is usually oversized.

The outdoor unit runs in winter. An air conditioner sits idle from October to May. A heat pump does not, and neighbors occasionally point this out as if something is wrong.

It will steam a few times a day when it is cold. That is the defrost cycle melting frost off the outdoor coil. It lasts a few minutes, the indoor air goes briefly cool, and it ends by itself. It is normal operation, not a fault.

Set the thermostat and leave it. Large setbacks work against a heat pump, because recovering four or five degrees pulls in expensive auxiliary heat. A steady setpoint, or a small setback of a degree or two, costs less than the deep night-time drop that saves money on a gas furnace.

What a Heat Pump Costs

A residential heat pump averages $6,087 installed, with most homeowners paying between $4,237 and $7,943 (Angi, 2026). The spread is driven mostly by system type, capacity and how much ductwork the job involves.

One thing to be clear about in 2026: the federal 25C tax credit that paid up to $2,000 toward a qualifying heat pump ended for equipment placed in service after December 31, 2025. Utility rebates in this region are still live. For the full breakdown by system type, and what actually moves your quote, see our guide to Heat Pump Cost in Philadelphia & NJ.

Talk to Someone Who Installs These

If you are weighing a heat pump against replacing a furnace and AC separately, Get in touch with Synergy3 Home Solutions. We are family-run out of Philadelphia, with 20 years in the trade, a 4.9-star rating, and 500+ Google reviews. Our hours are Monday to Friday 7:00 am to 7:00 pm and Saturday 7:00 am to 3:00 pm during peak season, with same-day service available on most calls.