Heat pump emergency heat typically costs about $0.65-$3.00 per hour to run, depending on the electric heat-strip size and local utility rate. Monthly bills vary with operating hours, outdoor temperature, and whether emergency heat is being used for a short repair delay or as a substitute for a failed heat pump.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Emergency heat per hour | $0.65 | $1.60 | $3.00 | Approx. 5-15 kW of resistance heat at $0.13-$0.20 per kWh |
| Daily use, 8 heating hours | $5.20 | $12.80 | $24.00 | Assumes strips draw full rated power while energized |
| One month, 8 hours daily | $156 | $384 | $720 | 30 days; actual cycling and utility rates change totals |
| Emergency heat repair | $150 | $500 | $1,500 | Diagnostic and common electrical or heat-strip repairs; major parts can cost more |
What emergency heat costs on a typical heat pump
Emergency heat, often marked “EM Heat” on a thermostat, usually switches off the outdoor heat-pump compressor and relies on electric resistance strips inside the air handler. The strips make heat directly from electricity, so each kilowatt-hour produces less heat than a heat pump normally delivers from the same electricity. The mode is intended for a malfunction or another short-term need, not routine winter heating.
For a common 10-kW strip kit, expect roughly $1.30-$2.00 for each hour the strips run continuously. This estimate uses residential electricity prices of $0.13-$0.20 per kWh and excludes taxes or fixed utility charges. A 5-kW setup costs about $0.65-$1.00 per full-power hour; a 15-kW setup costs about $1.95-$3.00.
Equipment capacity, not the thermostat label alone, determines the draw. Some air handlers have staged strips, so a 10-kW kit may energize only part of its capacity at first, then add another stage when the home needs more heat. The figures above represent full rated draw, not guaranteed consumption during every clock hour.
Assumptions: standard electric resistance backup, $0.13-$0.20 per kWh, no unusual demand charge, and full-power operation for the stated hours.
How heat-strip size and electric rates shape the bill
The basic operating estimate is heat-strip kilowatts multiplied by hours of operation and the electricity price per kilowatt-hour. A 10-kW strip running for six hours uses about 60 kWh. At $0.16 per kWh, that is $9.60 for the day before taxes and fees. If the strips cycle on and off, the actual total will be lower than a full six hours at rated power.
| Heat-strip capacity | Electricity per full hour | Hourly cost at $0.13-$0.20/kWh | Cost for 8 full hours |
|---|---|---|---|
| 5 kW | 5 kWh | $0.65-$1.00 | $5.20-$8.00 |
| 10 kW | 10 kWh | $1.30-$2.00 | $10.40-$16.00 |
| 15 kW | 15 kWh | $1.95-$3.00 | $15.60-$24.00 |
Every additional 5 kW of resistance heat adds about $0.65-$1.00 for each full hour at these utility rates. To estimate a monthly bill, multiply the hourly figure by the number of hours the strips actually run per day and by the number of days. For example, a 10-kW system running four full-power hours daily for 30 days adds about $156-$240, while eight hours daily adds about $312-$480.
Actual household bills may differ because a utility’s energy rate can fall outside the example range, and some plans have time-of-use pricing or demand charges. Check the per-kWh energy charge on the bill rather than dividing the total bill by total usage if fixed monthly fees are included.
What installers charge for strips, controls, and diagnosis
A repair quote depends on whether the problem is a failed heating element, sequencer, relay, fuse, thermostat, wiring connection, or control board. A service call and diagnosis commonly runs about $75-$200, with additional labor and parts. A straightforward electrical repair may total $150-$500; multiple failed components or difficult access can raise the bill to $500-$1,000 or more.
Replacing a heat-strip assembly can cost around $300-$1,000 for many residential systems, including parts and labor. Larger or less common assemblies, extensive wiring repairs, or replacement of an air handler may bring a project to $1,000-$3,000 or higher. These are broad U.S. estimates, not a guaranteed quote; the equipment model and local labor rates matter.
| Quote component | Typical range | What changes the charge |
|---|---|---|
| Diagnostic visit | $75-$200 | Trip distance, after-hours scheduling, and whether the fee is credited toward repair |
| Electrical repair labor | $100-$400 | About 1-3 hours; access and troubleshooting complexity |
| Relay, sequencer, fuse, or wiring part | $20-$250 | Part type, availability, and whether additional damage is found |
| Heat-strip assembly replacement | $300-$1,000 | Capacity, assembly design, labor, and air-handler access |
| Air-handler replacement | $1,500-$4,000+ | Capacity, duct changes, electrical work, and code requirements |
Ask whether the quote separates diagnosis, parts, labor, and any after-hours fee. A technician may charge a minimum service fee even when the repair takes less than an hour. Labor pricing often falls around $75-$150 per hour, though a flat-rate quote is also common.
Why a 10-kW kit can cost more than a 5-kW kit
Heat-strip capacity is one of the clearest cost drivers. A 5-kW kit draws about 21 amps at 240 volts, while a 10-kW kit draws about 42 amps and a 15-kW kit about 63 amps, before accounting for equipment-specific details. Larger strip banks can require more robust breakers, wiring, and air-handler components. A mismatch between the installed kit and the home’s electrical service can add upgrade work.
Runtime also changes sharply with conditions. A home that needs only two hours of backup heat per day has a very different bill from one where a failed compressor leaves the strips running most of the day. A 10-kW system at $0.16 per kWh costs $1.60 per full hour; four hours daily for a week is about $44.80, while 12 hours daily for the same week is about $134.40.
Long, cold-weather operation can multiply the bill even when the thermostat setting stays unchanged. Poor insulation, air leaks, a large temperature setback, and an undersized or malfunctioning heat pump can all increase demand. An indoor temperature drop followed by a large thermostat adjustment may keep backup strips energized for longer as the system tries to recover.
Utility rates are another major variable. At $0.12 per kWh, a 10-kW strip costs $1.20 per full hour; at $0.25 per kWh, it costs $2.50. The same 10-kW unit running eight hours a day for 30 days would therefore cost about $288 at the lower rate or $600 at the higher rate.
When emergency heat should stay on and when it should not
Emergency heat is generally for a heat-pump problem, such as an outdoor unit that will not operate, while a technician arranges service. Some thermostats also display “Aux Heat” when backup strips assist the heat pump during unusually cold weather or a temperature recovery. Auxiliary heat can operate alongside the compressor; emergency heat normally disables the compressor. The terminology and controls vary by thermostat and system.
If the outdoor unit works normally, leaving the thermostat on emergency heat can raise the bill without improving comfort. Use the setting as directed in the equipment manual or by a service professional. If the heat pump is making unusual noises, repeatedly tripping a breaker, or producing no heat, avoid repeated resets and request diagnosis rather than running an electrical fault indefinitely.
Do not assume that every cold-weather use of backup heat signals a defect. Heat pumps may need supplemental heat under certain outdoor conditions, and defrost cycles can temporarily affect the air temperature. A technician can determine whether the compressor, controls, refrigerant circuit, or strip heat is responsible for persistent backup operation.
Three household examples show the likely running expense
A small home with a 5-kW kit, an electricity rate of $0.14 per kWh, and three full-power hours per day would use about 15 kWh daily. That equals roughly $2.10 per day, or $63 over 30 days, if the strips run at full capacity for all three hours.
A typical 10-kW system at $0.16 per kWh running six full-power hours daily uses 60 kWh per day and costs about $9.60 daily. A week of this use is approximately $67.20; 30 days is about $288. This estimate does not include a service repair or changes in household electricity use.
A larger 15-kW kit at $0.20 per kWh running eight full-power hours daily would cost about $24 per day, or $720 in 30 days. That level of sustained use can justify calling for service promptly, especially if the compressor is not operating. The examples are billing calculations, not predicted run times for every home.
These totals assume continuous rated draw during each listed hour, so cycling and staged operation can reduce the actual charge. The thermostat may not show strip run time, and utility usage may be easier to verify by comparing daily kWh on the electric bill or meter during similar weather.
Regional electricity prices can change emergency heat totals
Electricity rates vary substantially by state, utility, and rate plan. At $0.12 per kWh, a 10-kW strip costs $1.20 per full hour; at $0.25, it costs $2.50. That difference produces a monthly range of $288-$600 for eight full-power hours each day over 30 days. Homes on time-of-use plans may pay more during peak hours, so the time the strips run can matter as well as total usage.
Contractor pricing also varies. Diagnostic visits and repairs in dense, high-cost metro markets may run roughly 10%-30% above comparable work in lower-cost rural areas. Rural service calls can include a longer travel charge or fewer available technicians, and severe cold snaps may limit appointment availability and increase after-hours fees.
Use the local utility rate for the operating estimate and local written quotes for repair pricing. National averages can help frame a budget, but they cannot capture a particular contractor’s minimum charge, the home’s electrical setup, or local permit and inspection requirements for substantial equipment changes.
How to lower the bill without sacrificing needed heat
First, confirm whether the thermostat indicates emergency heat or auxiliary heat and check the system manual. If emergency mode was selected accidentally and the heat pump is operating properly, switching back to the normal heat setting may avoid unnecessary strip use. If the outdoor unit is not functioning, do not disable backup heat when that would leave the home without safe heat; arrange service instead.
For a repair, compare two or three itemized quotes when the issue is not urgent. Ask whether a diagnostic charge applies toward the repair, whether the recommended part is available, and whether the price includes labor and testing. If replacement is proposed, request the repair alternative and the reason the existing component cannot be safely repaired.
Keeping emergency mode to the shortest safe period is usually the biggest controllable operating-cost decision. Avoid large thermostat increases that can trigger extended strip operation, and use normal insulation and air-sealing measures to reduce heat loss. Do not remove panels, handle high-voltage wiring, or install a larger strip kit without professional review; an improper electrical change can create a fire or shock hazard.
If the system needs frequent emergency heat, ask the technician to check heat-pump operation, thermostat setup, staging controls, and the home’s heating load. A recurring backup-heat bill may point to a repair or configuration problem rather than a need for a larger strip assembly. The least-cost option depends on diagnosis, expected repair life, and the cost of continued resistance heating.