Space heater cost calculator
How much does it cost to run a space heater? Enter its wattage, your electricity price and heating time to estimate the added cost per hour, per day and over a month.
16¢/kWh is an editable example, not a current Texas rate. Use the variable energy and delivery charges for your plan. 100% means continuous heating; 50% means the element runs for half the selected time.
$57.60 for 30 days
360 kWh · $1.92 per day · $0.24 per switched-on hour at the selected heating percentage.
Estimated additional usage cost for one heater. Existing fixed monthly fees are excluded. Bill credits, tiered rates, time-of-use prices and taxes can change the actual increase in your bill.
How much does it cost to run a space heater?
At the example rate of 16¢/kWh, a 1,500 watt electric heater costs $0.24 per hour of continuous heating. Running it for eight hours daily costs $1.92 per day, or $57.60 over 30 days. Your rate and thermostat behavior determine your result.
| Power | Hours/day | kWh/month | Cost/month |
|---|---|---|---|
| 750 W | 4 | 90 | $14.40 |
| 1500 W | 4 | 180 | $28.80 |
| 1500 W | 8 | 360 | $57.60 |
| 1500 W | 24 | 1080 | $172.80 |
How to calculate heater electricity usage
kWh = watts ÷ 1,000 × hours per day × days × active heating percentage ÷ 100. Cost = kWh × cents per kWh ÷ 100. Read the power on your heater’s label and use the setting you actually select.
The method and the example portable-heater range of 750–1,500 watts are supported by Virginia Cooperative Extension’s appliance energy-use guide. A 50% heating percentage is a scenario you choose, not a measured default for your home.
Which Texas electricity rate should I enter?
For a flat-rate plan, enter the variable energy charge plus the variable TDU delivery charge. An advertised average price can include fixed fees or conditional credits and may misstate the cost of extra heater usage.
A heater can also push your total usage across a bill credit threshold. Compare your whole bill before and after adding the heater’s kWh. For other appliances, use the kWh calculator; to compare listed plans, use the electricity bill calculator.
Published October 21, 2026. Calculations are estimates for the inputs shown, not provider quotes. Heating cost alone does not establish whether a space heater costs less than your central heating system.
Questions people ask
How much does it cost to run a 1500 watt heater for 24 hours?
At an illustrative 16 cents per kWh, a 1,500W heater running continuously uses 36 kWh and costs $5.76 for 24 hours. Over 30 days that is 1,080 kWh and $172.80. These are arithmetic examples, not a recommendation to run a heater unattended.
How do I calculate space heater electricity cost?
Divide watts by 1,000, multiply by the hours the heating element runs and by the electricity rate in dollars per kWh. Multiply the daily result by the number of days. At 1,500 watts, 8 hours and 16 cents per kWh, that is $1.92 a day.
Does a space heater use a lot of electricity?
A 1,500W heater uses 1.5 kWh for every hour of continuous heating. Eight hours a day for 30 days uses 360 kWh. A thermostat can reduce active heating time; enter the percentage of time actually heating to model that.
Is a 750 watt heater cheaper to run than a 1500 watt heater?
At the same electricity rate and active heating time, 750W uses half as much electricity as 1,500W. It also supplies less heat. If it has to run longer, the total saving can be smaller or disappear.