How to calculate the cost of running an appliance
Your utility bills you per kilowatt-hour (kWh): one kWh is 1,000 watts running for one hour. Multiply the device's average watts by the hours it runs, divide by 1,000 and multiply by your rate.
Example: a 1,500 W space heater running 4 hours a day at $0.18/kWh costs 1,500 × 4 ÷ 1,000 × 0.18 = $1.08 per day, about $33 per month.
Monthly cost of common appliances
At $0.18 per kWh (the 2026 US residential average according to the EIA) and typical daily use.
| Appliance (avg. draw × hours/day) | Per day | Per month | Per year |
|---|---|---|---|
| Refrigerator (full size) (55 W × 24 h) | $0.24 | $7.22 | $87 |
| Chest freezer (35 W × 24 h) | $0.15 | $4.60 | $55 |
| Window AC (8,000 BTU) (550 W × 8 h) | $0.79 | $24.08 | $289 |
| Space heater (high) (1,200 W × 4 h) | $0.86 | $26.27 | $315 |
| Electric blanket (60 W × 8 h) | $0.09 | $2.63 | $32 |
| TV (55" LED) (100 W × 4 h) | $0.07 | $2.19 | $26 |
| Desktop PC + monitor (250 W × 6 h) | $0.27 | $8.21 | $99 |
| Gaming PC + monitor (450 W × 4 h) | $0.32 | $9.85 | $118 |
| Wi-Fi router + modem (15 W × 24 h) | $0.06 | $1.97 | $24 |
| CPAP (no humidifier) (40 W × 8 h) | $0.06 | $1.75 | $21 |
| Washing machine (400 W × 1 h) | $0.07 | $2.19 | $26 |
| Microwave (1000 W) (1,500 W × 0.2 h) | $0.05 | $1.64 | $20 |
Fridges, freezers and AC units cycle on and off, so we use their average draw, not the label maximum.
Where to find your electricity rate
- Your utility bill shows the price per kWh, sometimes split into "supply" and "delivery". Add both for the real cost.
- Rates vary widely by state: from roughly 12¢ in some central states to over 30¢ in California, New England and Hawaii.
- On time-of-use plans, evening peak hours can cost two to three times more than nights.
How to lower the cost
- Measure real consumption with a plug-in energy meter for a few days. Label wattages are often far off.
- Replace space heaters with a heated blanket or a heat pump: the same comfort for a fraction of the energy.
- Shift big loads (laundry, dishwasher, EV charging) to off-peak hours if you're on a time-of-use plan.
- Solar panels or a solar-charged power station can cover small loads like routers and laptops. See how much solar you need.
Frequently asked questions
How much does it cost to run a refrigerator per month?
A modern full-size fridge averages about 55 W, roughly 1.3 kWh per day. At $0.18/kWh that is about $7.22 per month.
How much does it cost to run a space heater?
A 1,500 W heater on high costs about $0.27 per hour at $0.18/kWh, or around $53 per month if it runs 8 hours a day at an average of 1,200 W.
What is a kilowatt-hour?
A kilowatt-hour (kWh) is the energy used by a 1,000-watt device running for one hour. A 100 W TV needs 10 hours to use 1 kWh.
Why is my bill higher than the calculator?
Many devices draw standby power, older appliances use more than their label suggests, and your bill includes fixed fees and taxes. A plug-in energy meter shows the real numbers.