WattNoteSpace heater electricity cost calculator
Your appliance’s estimated energy cost
What this estimate uses
Calculation method and limits
Watts ÷ 1000 × hours × days gives energy. Multiply per-cycle energy by cycles; annual energy is used directly. Monthly and daily averages divide the annual estimate by 12 and 365. Seasonal bills, changing fixed charges, tiers and time-of-use rates are not predicted. Maximum label watts may differ from average power.
Use the detailed calculator
Calculate with your own usage
Formula reviewed: 2026-09-19 · Inputs: your measurements or product labels, not an official tariff database.
Enter average watts, daily hours and your heating season. This tool does not size a heater or estimate room heating performance.
Account for thermostat cycling once
If average power includes off periods, use total connected hours. If using active rated power, enter actual heating hours. Mixing both adjustments can double-count idle time.
Comparing with heat pumps
Equal electrical power need not deliver equal heat. Compare measured electricity under similar heating conditions. Insulation, outdoor temperature and heating efficiency are not automatically modelled.
Illustrative arithmetic
1000 average watts × 3 hours/day × 20 days/month × 4 months/year = 240 kWh/year. At an assumed 0.2 currency units/kWh, the cost is 48 currency units/year.
Cost does not determine safety
Reduced-use scenarios do not determine heating needs or safe operation. Follow the product instructions for clearance and use.