Calculate how much any appliance costs to run
The electricity cost of any device depends on three things: its power rating in watts, how many hours per day you use it, and what you pay per kilowatt-hour (kWh). The formula is simple:
Daily cost = (Watts × Hours) ÷ 1,000 × Price per kWh
A 1,500W space heater running 6 hours a day at $0.20/kWh costs $1.80 per day — $54 per month, $657 per year. That single appliance can be your biggest electricity expense in winter.
| Appliance | Typical wattage | Daily use | Monthly cost* |
|---|---|---|---|
| Space heater | 1,500 W | 6 h | ~$54 |
| Air conditioner | 1,200 W | 8 h | ~$58 |
| Electric oven | 2,000 W | 1 h | ~$12 |
| Refrigerator | 150 W | 24 h | ~$22 |
| Washing machine | 500 W | 1 h | ~$3 |
| Dishwasher | 1,200 W | 1 h | ~$7 |
| TV (55") | 100 W | 5 h | ~$3 |
| LED light bulb | 10 W | 8 h | ~$0.48 |
| Desktop PC | 300 W | 8 h | ~$14 |
| EV charger (L2) | 7,200 W | 2 h | ~$86 |
* Based on $0.20/kWh. Adjust using the calculator above for your local rate.
The wattage is usually printed on a label on the back or bottom of the appliance, or in the user manual. It may be listed as watts (W) or kilowatts (kW) — multiply kW by 1,000 to get watts. For devices with variable power (like laptops or TVs with brightness settings), use the typical operating wattage rather than the maximum.
If you cannot find the label, a plug-in energy monitor (smart plug with energy monitoring) will give you the real wattage under actual operating conditions — often lower than the rated maximum.
The highest-impact changes are almost always related to heating and cooling. Replacing a 1,500W resistive space heater with a modern heat pump can cut heating electricity use by 60–70% for the same warmth output. Improving insulation reduces heating and cooling demand at the source.
For other appliances: running your washing machine on cold wash saves 80–90% of the energy versus a hot wash (most of the energy goes to heating water, not spinning). Switching from incandescent to LED bulbs cuts lighting costs by 80–90%. Unplugging devices on standby eliminates phantom load — typically 5–10% of a household electricity bill.
What you pay per kWh varies dramatically by country. As of 2025, the global residential average is approximately $0.17/kWh, but European countries like Germany and Denmark pay $0.35–0.40/kWh, while the US averages around $0.16/kWh and parts of Asia pay as little as $0.08/kWh. Your electricity bill should show your exact rate — look for the unit rate or price per kWh on the tariff summary page.
Multiply the wattage by hours used per day, divide by 1,000 to get kWh, then multiply by your electricity rate. A 2,000W oven running 1 hour at $0.20/kWh costs 2 × 1 ÷ 1,000 × $0.20 = $0.40 per use.
1,500W × 24h ÷ 1,000 = 36 kWh. At $0.20/kWh that is $7.20 per day, or about $216 per month if run continuously.
A modern 55-inch LED TV uses roughly 80–120W. At 5 hours per day and $0.20/kWh: 100W × 5h × 30 days ÷ 1,000 = 15 kWh = $3.00 per month.
Heating and cooling systems account for 40–50% of a typical household electricity bill. Water heating is second at 14–18%. Everything else — appliances, lighting, electronics — makes up the remainder.
Check your electricity bill — the rate is usually listed as cents per kWh or price per unit. In the US, average rates range from about 10 cents (states with cheap hydro power) to 30+ cents per kWh (Hawaii, California). European rates are generally higher due to taxes and grid fees.