How to use it
- Enter the floor area and ceiling height.
- Choose the insulation level (or set watts per cubic foot).
- Enter daily hours, thermostat duty cycle and your $/kWh rate.
- Read the wattage, suggested panels and running cost.
How much wattage does a room need?
The calculator multiplies the room's volume by a watts-per-cubic-foot factor for the insulation level: about 0.7 W/cu ft for good insulation, 1 W/cu ft for average and 1.3 W/cu ft for poor. It then suggests a combination of up to four common panel sizes (300, 450, 600, 720, 900 and 1,200 W) that covers the need, preferring fewer panels.
Example: a 160 sq ft room with 8 ft ceilings is 1,280 cu ft. With average insulation that's about 1,270 W, so the suggestion is 720 W + 600 W = 1,320 W.
Running cost
Cost = panel watts ÷ 1,000 × hours on × duty cycle × price per kWh.
The duty cycle is the share of time the thermostat actually has the panel on. On mild days it might be 30–40%, in a cold snap 70–100%. Continuing the example, 1,320 W for 10 hours a day at 50% duty uses 6.6 kWh per day. At $0.17 per kWh that's about $1.12 a day, $34 a month and about $200 over a 180-day heating season.
Use the rate from your electric bill, including delivery charges. Rates vary a lot by state and utility, and some plans charge more at peak times.
Infrared panels vs. heat pumps and space heaters
| Heater | Heat per kWh of electricity |
|---|---|
| Infrared panel, oil-filled radiator, fan heater, baseboard | about 1 kWh (100% efficient at the point of use) |
| Ductless mini-split heat pump | typically 2.5–4 kWh, depending on model and outdoor temperature |
All electric resistance heaters, infrared or not, turn electricity into the same amount of heat. Infrared panels feel warm quickly because they heat people and surfaces directly rather than the air, which suits rooms you use occasionally, bathrooms and home offices. For whole-home heating, a heat pump usually costs far less to run; the electricity cost calculator helps compare appliances.
Electrical and placement tips
- A standard 120 V, 15 A household circuit can supply about 1,500 W for a plug-in heater; don't put two large heaters on the same circuit.
- Larger or hard-wired panels (240 V) need a dedicated circuit installed by an electrician.
- Mount ceiling or high wall panels so they "see" the area where people sit; furniture in between blocks the radiant heat.
- Use a thermostat; it's what keeps the duty cycle, and the bill, down.
- Keep panels away from curtains and follow the manufacturer's clearances.
Accuracy
The watts-per-cubic-foot factor is a rule of thumb, not a heat loss calculation. Climate, window area and air leaks change the real need considerably. Treat the result as a starting point for comparing panel sizes and costs.
Frequently asked questions
How many watts of infrared heat do I need per square foot?
Roughly 6–10 W per square foot for a room with 8 ft ceilings, depending on insulation. The calculator uses the room volume for a better estimate.
How much does it cost to run a 1,000 W infrared heater?
1 kWh per hour at full power. At $0.17/kWh that's 17 cents an hour, or about 8.5 cents an hour at a 50% duty cycle.
Are infrared heaters more efficient than other electric heaters?
No, all resistance heaters convert electricity to heat at the same rate. Infrared can feel more comfortable at a lower air temperature because it warms you directly.
Is an infrared heater cheaper than a heat pump?
To buy, usually yes; to run, no. A heat pump delivers several times more heat per kWh.
Can I plug an infrared panel into a regular outlet?
Plug-in models up to about 1,500 W can go on a standard 120 V outlet. Larger panels may need a dedicated or 240 V circuit.
Last updated: November 12, 2026