Running heat strips typically costs about $0.65-$4.00 per hour, depending on strip capacity, electricity rates, and how long the strips operate. A common 10-kilowatt system costs roughly $1.70 per hour at a $0.17-per-kWh rate, while colder weather and frequent auxiliary-heat use can raise monthly bills quickly.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Cost per operating hour | $0.65 | $1.70 | $4.00 | 5-20 kW strips at $0.13-$0.20/kWh |
| Four hours of use per day | $2.60 | $6.80 | $16.00 | Daily electricity expense |
| 30-day month, four hours daily | $78 | $204 | $480 | Assumes the same runtime each day |
| Cost per delivered kWh of heat | $0.13 | $0.17 | $0.20 | Resistance heat converts electricity to heat at the point of use |
What a 5- to 20-kW heat strip costs to run
Heat strips use electric resistance to produce heat. The simplest estimate multiplies the strip’s kilowatt rating by its operating hours and the home’s electricity price. At $0.17 per kWh, a 5-kW strip costs about $0.85 an hour; a 10-kW strip costs $1.70; and a 20-kW strip costs $3.40. At the higher assumed rate of $0.20, a 20-kW system reaches $4 an hour.
For a typical 10-kW strip, budget about $1.70 for each hour it runs at the national-use example rate. A 10-kW rating does not mean the equipment runs continuously whenever the thermostat calls for heat; actual consumption depends on controls, outdoor temperature, and heat demand. Assumptions: $0.17/kWh electricity, full rated output, no demand charges or time-of-use adjustment.
How electricity use translates into the utility bill
The key cost components are the strip’s capacity, its runtime, and the rate on the electric bill. The table shows full-output estimates at the average example rate; shorter cycles lower the total proportionally.
| Strip capacity | Electricity used per hour | Cost per hour | Cost at 4 hours daily | 30-day total |
|---|---|---|---|---|
| 5 kW | 5 kWh | $0.85 | $3.40 | $102 |
| 10 kW | 10 kWh | $1.70 | $6.80 | $204 |
| 15 kW | 15 kWh | $2.55 | $10.20 | $306 |
| 20 kW | 20 kWh | $3.40 | $13.60 | $408 |
Every additional hour of full-output operation adds about $0.17 per kW at this rate. For a calculation using a different utility rate, use ; for labor-free operating estimates, no installation labor charge is included.
Why strip size and electric rates change the estimate
Capacity and the price per kilowatt-hour are the biggest drivers. A 15-kW strip consumes three times as much electricity per hour as a 5-kW strip. Utility rates vary widely, so a 10-kW strip costs $1.30 an hour at $0.13/kWh, $1.70 at $0.17, and $2.00 at $0.20. Check the bill’s energy charge rather than relying on a national average.
Controls can stage multiple heating elements instead of switching the entire bank on at once. For example, a 15-kW assembly that energizes only 5 kW for a portion of an hour uses less than a full hour at 15 kW. Thermostat settings, heat-pump condition, insulation, and outdoor temperature also affect how many hours the strips run.
A 5-kW change in strip capacity shifts full-output cost by about $0.65-$1 per hour across the example rate range. Confirm the installed strip rating on the equipment label or service documentation; the air handler’s maximum supported capacity may differ from the amount energized in normal operation.
How many hours do auxiliary heat strips usually run?
Heat strips paired with a heat pump are often auxiliary or emergency heat, not the home’s primary heat source. They may operate briefly when outdoor temperatures are low, when the thermostat is raised several degrees at once, or during a defrost cycle. If strips run four hours daily, a 10-kW system costs about $204 monthly at $0.17/kWh. Eight hours daily doubles that estimate to $408.
Runtime matters as much as the strip’s nameplate size. A utility bill alone cannot identify strip usage because it includes other appliances, but a sudden winter increase can be compared with the system’s rated kilowatts and likely operating hours. A technician can check whether staging and thermostat settings are working as intended.
Three household runtime examples at $0.17 per kWh
A 5-kW strip running two hours daily uses 10 kWh a day and costs about $1.70 daily, or $51 over 30 days. A 10-kW strip running four hours daily uses 40 kWh a day and costs $6.80 daily, or $204 monthly. A 15-kW strip running six hours daily uses 90 kWh a day and costs $15.30 daily, or $459 monthly.
These examples assume full rated output for every stated hour. Real equipment may cycle on and off or stage elements, so measured consumption can be lower. If a system has a time-of-use plan, calculate each operating period at its applicable rate.
When heat strips cost more than a heat pump
Heat strips usually cost more to operate than a functioning heat pump because resistance elements consume roughly one kWh of electricity for each kWh of heat delivered. A heat pump can move heat rather than generate all of it electrically, so it may provide several times as much heat per unit of electricity under suitable conditions. Its advantage shrinks in severe cold, and backup strips may be needed to maintain comfort.
Frequent strip operation can signal a comfort or equipment issue, not just a high utility rate. A dirty filter, low refrigerant, poor airflow, or a large thermostat setback can increase auxiliary-heat use. Diagnosis and repair pricing varies by fault; compare the service quote with the likely monthly savings before authorizing major work.
Ways to lower heat strip use without sacrificing comfort
Keep thermostat changes gradual, replace clogged filters, and use a moderate setpoint rather than making large recovery jumps after a setback. Avoid selecting emergency heat unless the heat pump is malfunctioning or a technician recommends it, since that setting can rely heavily or entirely on resistance strips. Weather sealing and insulation improvements can reduce the home’s heat demand, though their price depends on the affected area and materials.
Ask a technician to verify staging before replacing a properly sized system. When comparing service estimates, request the strip capacity, expected operating condition, diagnostic charge, and whether the proposed work addresses auxiliary heat running too often. This helps distinguish normal cold-weather backup use from a control or equipment problem.