Heating Cost Calculator

How to use the heating cost calculator

Enter the heater’s wattage, how many hours a day it runs, and over how many days, plus your electricity rate, and you get the cost to run it. It’s the same energy-times-rate math as any electric load, framed for space heating — where the numbers are large and the misconceptions plentiful. The rate varies by state; the US average is about 17.5¢/kWh as of 2026, so use your own bill.

The “cheap heater” myth is the one to clear up first. Every 1,500 W electric resistance heater — ceramic, oil-filled, fan-forced, “infrared,” twenty dollars or two hundred — costs exactly the same to run, because they all convert the same watts into the same amount of heat. Resistance heating is 100% efficient at making heat, so wattage and runtime are the only things that set the cost. A pricier heater isn’t cheaper to run; it just looks nicer doing it.

That 100% sounds unbeatable until you meet the heat pump, which moves heat rather than making it and delivers two to four units of heat per unit of electricity — a coefficient of performance (COP) of 2 to 4. For the same warmth, a heat pump costs a third to a half of resistance heat. If you’re heating a space for hours a day through a season, that gap, not the heater’s sticker price, is where the real money is.

Run the space-heater-per-room math and it adds up fast. A 1,500 W heater on 8 hours a day for a month is 360 kWh, about $63 at $0.175 — per room. Two or three rooms and you’re paying more than central heating would cost. Space heaters genuinely win for brief, targeted warmth — an hour in the one room you’re using — but they lose badly as a whole-home or all-day solution.

To size the heating itself rather than just price a heater’s draw, the BTU calculator works out how much heating power a room actually needs from its volume and conditions. Use this tool for the running cost, the BTU calculator for the right capacity, and the electricity-cost calculator for any other device — and seriously weigh a heat pump before resistance heat for anything you’ll run a lot.

The formula

Heating cost is the same energy-times-rate math as any electric load — resistance heaters turn 100% of their watts into heat:

kWh = (watts ÷ 1000) × hours per day × days
cost = kWh × rate

Worked example with the defaults — a 1,500 W heater, 8 hours a day for 30 days at $0.175/kWh: (1500 ÷ 1000) × 8 × 30 = 360 kWh, times $0.175 = $63.00 ($2.10 a day). A 5,000 W heater run the same way is 1,200 kWh and $210.

A heat pump delivering the same warmth at a COP of 3 would use a third of the electricity — about $21 instead of $63. Among resistance heaters, though, wattage is everything: every 1,500 W unit costs the same to run.

Frequently asked questions