How much does it cost to run an appliance?
Short answer: cost = watts × hours ÷ 1,000 × your price per kWh. At 18 cents per kWh, a 1,500-watt space heater costs 27 cents an hour, and a 10-watt Wi-Fi router left on all year costs about $16. Add your own devices below to see your total and which one costs the most.
1. Your devices
Watts are typical values. Check the label on your device for its real number. Hours means hours a day it actually draws power.
18¢ is close to the U.S. Energy Information Administration's forecast 2026 average. Your bill shows your real rate: divide the total charge by the kWh used.
2. What it costs
- Per day
- $2.55
- Per month
- $76.57
- Per year
- $931.63
14.18 kWh a day
30 days
365 days of the same use
| Device | Per hour running | Per month | Share |
|---|---|---|---|
| Space heater (high) | 27.0¢ | $64.80 | 85% |
| Refrigerator (average draw) | 1.1¢ | $7.78 | 10% |
| TV (55-inch LED) | 1.8¢ | $2.70 | 4% |
| Wi-Fi router | 0.2¢ | $1.30 | 2% |
How this is calculated
- kWh per day = watts × hours per day × quantity ÷ 1,000.
- Cost = kWh × your price per kWh (18¢).
- Devices with a thermostat (heaters, fridges, dehumidifiers) switch on and off, so they draw full watts only part of the time. Enter the hours they actually run, or use a plug-in meter to measure.
How to find a device's watts
- The label or nameplate lists watts, or amps and volts. Watts ≈ amps × volts, but this is a maximum, not what the device usually draws.
- The yellow EnergyGuide label on fridges, TVs and some other appliances lists yearly kWh. Divide by 365 for kWh per day.
- A plug-in electricity meter measures real use over a day or a week. It is the most accurate option for anything with a thermostat or a standby mode.
Worked examples at 18¢ per kWh
| Device | Use | kWh per month | Cost per month |
|---|---|---|---|
| 1,500 W space heater | 8 hours a day | 360 | $64.80 |
| Refrigerator (524 kWh/yr label) | always on | about 44 | about $7.86 |
| 100 W TV | 5 hours a day | 15 | $2.70 |
| 10 W Wi-Fi router | 24 hours a day | 7.2 | $1.30 |
Months are 30 days. The fridge figure uses an ENERGY STAR-certified model's yearly rating divided by 12.
Guides for specific appliances
- How much it costs to run a space heater
- How many watts a refrigerator uses
- How much electricity a TV uses
- Electric fireplace running cost
- Christmas lights running cost
- Standby power: what devices use when off
- How to lower your electric bill in winter