What is the difference between heat strips and a heat pump?
The difference is that a heat pump moves heat while heat strips make it, and that one distinction drives everything else. A heat pump uses a refrigerant cycle to pull heat out of the outdoor air and carry it inside, so it delivers far more heat than the electricity it consumes. Heat strips are electric resistance coils that glow and warm the air passing over them, exactly like a space heater or a toaster, turning each watt into the same amount of heat and no more.
In most homes these two are not separate systems you pick between; they are parts of the same system. The strips sit inside the heat pump's air handler as auxiliary (aux) or emergency heat, wired to kick in when the heat pump needs help. That is why comparing them is really a question of roles: the heat pump should carry your normal heating load, and the strips should only step in when it cannot keep up. If your setup is all electric and has no heat pump at all, an electric furnace is essentially a big bank of heat strips; see gas furnace vs electric furnace for that version of the choice.
Which is cheaper to run, heat strips or a heat pump?
A heat pump is far cheaper to run, usually about three to four times cheaper for the same amount of heat. The reason is efficiency, not the price of electricity. A heat pump runs at a coefficient of performance (COP) around 3 to 4 in mild-to-moderate cold, meaning it delivers three to four units of heat for every unit of electricity. Heat strips run at a COP of about 1.0, so they deliver exactly one unit of heat per unit of electricity. Same power bill inputs, three to four times the output for the heat pump.
This is why leaning on strip heat is expensive. A typical air handler carries 5 to 20 kilowatts of strip heat, and a 10 kW element burning for one hour uses 10 kilowatt-hours, the same energy as running ten space heaters. When the strips run for hours during a cold snap, the meter spins hard. The gap does narrow as it gets very cold, because a heat pump's COP drops toward 2 or even lower near its limits, but even then the heat pump still wins. If you want to check the heat your home actually needs before sizing anything, start with our BTU calculator.
When do heat strips actually run?
Heat strips run when the heat pump cannot meet the heating demand on its own, and a good thermostat brings them on automatically. The most common trigger is temperature: below a crossover point, often around 35°F but it depends on your home and equipment, the heat pump can no longer keep up, so the aux heat strips fill the gap. They also fire briefly during the defrost cycle, when the heat pump reverses to melt frost off the outdoor coil and needs the strips to keep indoor air from blowing cold.
The two settings people confuse are aux heat and emergency heat. Aux heat runs the strips alongside the heat pump automatically when it needs a boost. Emergency heat shuts the heat pump off entirely and heats with the strips alone, which you only use if the heat pump has actually failed, because it is the most expensive way to heat. Setting a thermostat back by a large amount and then asking for a quick recovery also wakes the strips up, so deep setbacks can cost more than they save on a heat pump. For the full breakdown, see what aux heat means on a thermostat.
Should you heat with strip heat or a heat pump?
Heat with the heat pump and let the strips stay in the backup role they were built for. Running strip heat as your main source is what produces those shocking winter electric bills, and it is usually a sign the heat pump is undersized, mis-set, or being overridden into emergency heat. If your bill spikes with a heat pump, the strips are almost always the reason, not the heat pump itself.
In a genuinely cold climate, the smart move is a cold-climate (hyper-heating) heat pump that keeps working efficiently down to much lower temperatures, which keeps the expensive strips off far longer. Some homes pair a heat pump with a gas furnace instead, a setup called a dual-fuel or hybrid system, so gas takes over in deep cold rather than resistance heat. Either way, the goal is the same: keep the heat pump doing the work and treat strip heat as the emergency brake, not the engine. Weigh the honest tradeoffs in the disadvantages of a heat pump.
Heat strips wins on
- +Cheap to install, built into the heat pump's air handler
- +Full heat output at any outdoor temperature, even below zero
- +Instant backup and defrost heat when the heat pump needs help
Heat pump wins on
- +About 3x to 4x cheaper to run for the same amount of heat
- +One system heats in winter and cools in summer
- +Carries the whole heating load in most climates, keeping the strips off
The verdict
Make the heat pump your primary heat and keep the strips as backup only. A heat pump heats for roughly a third the cost of resistance strips, so the more hours it runs on its own, the lower your bill. Let aux heat cover the coldest snaps and defrost cycles, and reserve emergency heat for when the heat pump has actually broken down. If you live somewhere with hard winters, buy a cold-climate heat pump or a dual-fuel setup rather than relying on strip heat, because strip heat run for long stretches is what turns a heat pump into an expensive way to heat. Size the system to your real load first with the BTU calculator, and compare heating options in heat pump vs furnace.
Related: What Aux Heat Means on a Thermostat, Disadvantages of a Heat Pump, Heat Pump vs Furnace, BTU Calculator.
Frequently asked questions
Are heat strips expensive to run?
Yes. Heat strips run at a COP of about 1.0, so they cost roughly three to four times as much as a heat pump to deliver the same amount of heat. A typical air handler holds 5 to 20 kilowatts of strip heat, and a 10 kW element uses 10 kilowatt-hours for every hour it runs, so a cold snap that keeps the strips on for hours drives the bill up fast.
What are the drawbacks of using heat strips?
The main drawback is running cost, since strip heat is the least efficient way to heat a home electrically. They also do nothing in summer, and relying on them as a primary heat source usually points to an undersized or mis-set heat pump. Their one real advantage is that they put out full heat at any temperature, which is why they make good backup and emergency heat rather than a main heat source.
At what temperature does a heat pump switch to auxiliary heat strips?
Most systems bring on aux heat below a crossover point that is often around 35°F, though the exact temperature depends on your home, your heat pump's capacity, and how the thermostat is set. Below that point the heat pump can no longer meet the heating demand on its own, so the strips fill the gap. A properly sized heat pump and a well-configured thermostat keep that crossover point as low as possible to hold the strips off.
Why is my electric bill so high with a heat pump?
In almost every case the culprit is the backup heat strips running, not the heat pump itself. If the heat pump is undersized, the thermostat is left in emergency heat, or you use deep setbacks that force a fast recovery, the resistance strips end up doing hours of work at three to four times the cost. Check whether the thermostat is calling aux or emergency heat, and have a tech confirm the heat pump and crossover point are set correctly.
Should heat strips be my main source of heat?
No. Heat strips are meant to back up a heat pump, not replace it, because resistance heat costs roughly three to four times more to run. Let the heat pump carry the normal load and use the strips only for the coldest days, defrost cycles, and true emergencies. In cold climates, a cold-climate heat pump or a dual-fuel system keeps the strips off far longer than relying on them.