Formula
kWh = Watts ÷ 1,000 × Hours
Cost = kWh × Price per kWh
Cost = kWh × Price per kWh
Example: A 1,500 W heater running 8 hours a day for 30 days uses 360 kWh. At $0.175 per kWh that costs $63.00 — $0.26 an hour or $2.10 a day. With a thermostat keeping it on 60% of the time, the cost drops to about $37.80.
Other appliances
- Window AC unit: 500–1,500 W · Dehumidifier: 300–700 W
- Electric blanket: 50–200 W — a cheap way to stay warm at night
Sizing an air conditioner? Use the BTU calculator.
Frequently asked questions
How much does it cost to run a 1,500 W space heater?
At $0.175 per kWh, about $0.26 an hour. Eight hours a day for 30 days costs about $63.
Do space heaters use a lot of electricity?
Yes — 1,500 W is one of the highest loads in a home. Heating one room with a space heater can still save money if you turn the central heat down.
Are some space heaters more efficient?
All electric resistance heaters convert 100% of electricity into heat. Oil-filled and ceramic heaters differ in comfort, not efficiency. Heat pumps are 2–4× more efficient.
How can I lower the cost?
Use the low setting (750 W), a thermostat, a timer, and heat only the room you are in with the door closed.