Heat pumps are more efficient than most furnaces and air conditioners, but the difference depends on your climate and what you're replacing
A heat pump moves heat instead of generating it, which uses less energy than burning fuel or running a resistance heater. In moderate climates, a heat pump can deliver two to three times more heating or cooling energy than the electricity it consumes. A traditional furnace converts fuel into heat at roughly 80 to 95 percent efficiency—meaning 5 to 20 percent of the energy is lost. A heat pump's efficiency advantage shrinks in very cold climates, where it may need a backup heater and performs closer to a high-efficiency furnace. The real comparison depends on what system you currently have, your local climate, and your electricity costs versus fuel costs.
Key Takeaways
- Heat pumps deliver more heating or cooling energy than the electricity they use, while furnaces and air conditioners convert fuel or electricity into heat at lower rates.
- In climates where winter temperatures rarely drop below freezing, a heat pump typically costs less to operate than a gas furnace or electric resistance heater.
- In very cold climates, a heat pump's efficiency drops and it may run a backup heater, narrowing the savings compared to a high-efficiency furnace.
- The total cost difference includes the upfront price of the unit, installation, and how long you plan to stay in the home.
How heat pump efficiency is measured
Heat pump efficiency is rated using HSPF (Heating Seasonal Performance Factor) for heating and SEER2 (Seasonal Energy Efficiency Ratio) for cooling. These numbers represent the total heating or cooling output divided by the total electricity input over a season. A heat pump with an HSPF of 8 delivers eight units of heat for every unit of electricity it uses. Modern heat pumps range from HSPF 8 to 13 for heating and SEER2 8 to 22 for cooling, depending on the model and brand.
Furnaces are rated by AFUE (Annual Fuel Utilization Efficiency), which measures the percentage of fuel that becomes usable heat. A furnace with 95 percent AFUE wastes 5 percent of the fuel as exhaust. Central air conditioners use SEER2, the same standard as heat pumps. The key difference: a heat pump's HSPF and SEER2 both measure energy moved, not energy created, so the numbers reflect a fundamentally different process.
Heat pumps versus gas furnaces in moderate climates
In a climate where winter lows rarely fall below 30°F and you heat for four to six months per year, a heat pump typically costs less to operate than a gas furnace. Even if your furnace is 95 percent efficient, the heat pump is moving existing heat rather than creating it, so it uses roughly 30 to 50 percent less energy for the same output. The operating cost advantage grows if your local electricity rates are low relative to natural gas prices, and shrinks if gas is much cheaper than electricity in your area.
The upfront cost of a heat pump is usually $5,000 to $15,000 installed, compared to $3,000 to $8,000 for a furnace replacement. If you plan to stay in the home for 10 or more years, the lower operating costs often recover the higher purchase price. If you plan to move within five years, the payback period may extend beyond your time in the home.
Heat pumps in cold climates and backup heating
Below about 25°F to 30°F, a heat pump's efficiency drops because the outdoor air contains less heat to extract. Most cold-climate heat pumps are sized to handle heating down to around 0°F, but they run a backup electric resistance heater or gas furnace for the coldest days. When the backup heater runs, the system's overall efficiency approaches that of a furnace or electric resistance heater, erasing much of the advantage.
Newer cold-climate heat pumps (sometimes called "cold-climate-rated" models) maintain higher efficiency down to -13°F or lower, but they cost more upfront and are not available from all manufacturers. In regions where temperatures regularly drop below 0°F, a high-efficiency gas furnace paired with a heat pump for shoulder seasons (fall and spring) may deliver better overall efficiency and lower operating costs than a heat pump alone.
Cooling efficiency: heat pumps versus air conditioners
A heat pump and a central air conditioner use the same cooling technology and have nearly identical SEER2 ratings when both are modern units. The efficiency difference in cooling is negligible. The advantage of a heat pump is that it handles both heating and cooling with one outdoor unit, eliminating the need for a separate furnace. If you're replacing an old air conditioner and furnace, a heat pump does the work of both, but you're not gaining cooling efficiency—you're gaining heating efficiency and simplifying the system.
Electricity costs and operating expenses
The real-world savings depend on how much you pay per kilowatt-hour of electricity and per therm (or gallon) of natural gas. In states where electricity is cheap and gas is expensive—such as the Pacific Northwest—a heat pump saves significantly. In states where gas is cheap and electricity is expensive—such as parts of the Midwest—the savings are smaller or may not exist. Your utility bills from the past year show your local rates; you can calculate the annual cost difference by comparing the energy use of your current system to the heat pump's rated efficiency.
A heat pump also eliminates the cost of a gas line inspection and annual furnace maintenance, though it requires professional refrigerant service if it develops a leak. Over 15 years, these maintenance differences are usually small.
When a heat pump is not the most efficient choice
If you live in a climate where winter temperatures stay below 0°F for weeks at a time, a high-efficiency gas furnace may deliver lower operating costs and simpler operation. If your home has no existing ductwork and you cannot afford to install it, a ductless mini-split heat pump is an option, but it costs more per ton of capacity than a ducted system. If you heat with oil or propane and electricity rates are very high, replacing the furnace with a heat pump may not save money despite the efficiency advantage.
The most efficient choice is the one that matches your climate, your utility rates, your home's layout, and how long you plan to stay. A professional HVAC contractor can model the operating costs of a heat pump versus your current system using your local rates and heating and cooling needs.
Frequently Asked Questions
Will a heat pump work if I have a gas furnace now?
Yes. A heat pump can replace a furnace entirely in moderate climates, or work alongside it as a backup in cold climates. If your home has ductwork, the heat pump uses the same ducts. If it doesn't, you can install a ductless system, though that costs more. Your contractor will assess whether your current system's ducts and electrical service can support a heat pump.
How much will I save on my heating bill?
Savings vary widely by climate and local utility rates. In mild climates with low electricity costs, savings can reach 30 to 50 percent. In cold climates or areas with expensive electricity, savings may be 10 to 20 percent or zero. Your utility bills and a contractor's load calculation are the only reliable way to estimate your specific savings.
Do heat pumps work in freezing weather?
Yes, but with reduced efficiency. Most heat pumps operate down to 0°F or below, though they may run a backup heater on the coldest days. Cold-climate models work efficiently to -13°F or lower. Below that, or when outdoor temperatures drop very far, the backup heater provides most of the warmth.
Is a heat pump more efficient than an old air conditioner and furnace?
Almost certainly yes, because modern heat pumps are more efficient than systems installed 10 or more years ago. A single modern heat pump is more efficient than an old furnace and old air conditioner combined. The efficiency gain is largest if your current system is over 15 years old.
What if I have electric resistance heat now?
A heat pump is almost always more efficient than electric resistance heating, regardless of climate. Resistance heaters convert electricity to heat at 100 percent efficiency, but a heat pump delivers two to three times more heat per unit of electricity. Switching from resistance heat to a heat pump typically cuts heating costs in half.