How Much Does It Cost to Run a Space Heater?

Quick answer: A 1,500-watt electric space heater running continuously at full power uses 1.5 kilowatt-hours (kWh) of electricity per hour. At the U.S. residential average electricity price of 18.31¢ per kWh in July 2026, that works out to about 27¢ per hour, $2.20 for 8 hours, or $65.92 for 8 hours a day over 30 days. Your actual cost can be higher or lower depending on your electricity rate, heater wattage, and how often the thermostat cycles the heating element on and off.

Space Heater Running Cost at a Glance

Important: These are full-power estimates, not a promise of what your bill will increase by. A thermostatically controlled heater may cycle off after the room reaches the set temperature, while a poorly insulated or very cold room may keep it running much longer.

How to Calculate Your Own Space Heater Cost

You only need three numbers: the heater’s wattage, how long it runs, and your electricity price in dollars per kWh. If you want a quick refresher on the unit itself, see what a kWh is and how to read it on your electric bill.

Step 1: Convert watts to kilowatts.
Watts ÷ 1,000 = kilowatts

For a 1,500-watt heater: 1,500 ÷ 1,000 = 1.5 kW.

Step 2: Calculate electricity use.
Kilowatts × hours of operation = kWh

For 8 hours at full power: 1.5 kW × 8 hours = 12 kWh.

Step 3: Calculate the cost.
kWh × electricity rate = operating cost

Using 18.31¢/kWh, or $0.1831/kWh: 12 × $0.1831 = $2.20 for 8 hours of continuous full-power operation.

How Much Does a Space Heater Cost Per Hour?

At 18.31¢/kWh, a 1,500-watt heater costs about 27¢ per hour while its heating element is drawing the full 1,500 watts. A lower-wattage heater costs less per hour at full power because it draws less electricity.

How Much Does a Space Heater Cost to Run for 8 Hours?

If a 1,500-watt heater draws full power for all 8 hours, it uses 12 kWh. At 18.31¢/kWh, the estimated cost is $2.20.

Do that every day for 30 days and the full-power estimate becomes about $65.92 per month. But this is best treated as an upper-end runtime example rather than a universal monthly cost. Thermostats, temperature settings, room conditions, and user behavior can reduce the amount of time the heating element actually draws full power.

Why Your Actual Space Heater Cost May Be Different

Your Electricity Rate

The 18.31¢/kWh figure used above is a national residential average, not the rate every household pays. Electricity prices vary by state, utility, rate plan, and sometimes time of day. For the most useful estimate, use the price from your own electric bill.

Heater Wattage

Check the heater’s label or manual for its rated wattage. A 750-watt setting uses half as much electricity per hour as a 1,500-watt setting while both are continuously drawing their rated power.

How Long the Heating Element Actually Runs

A heater with a thermostat may stop drawing full heating power once the room reaches the set temperature and turn back on as the room cools. That means “8 hours plugged in” does not necessarily mean 8 hours at the heater’s maximum wattage.

Room Size and Heat Loss

A drafty room, open door, poor insulation, or very low outdoor temperature can make a heater work longer to maintain the same indoor temperature. Improving obvious air leaks can therefore matter as much as comparing heater designs.

Are More Expensive Space Heaters Cheaper to Run?

Not automatically. If two electric resistance heaters are both drawing 1,500 watts, each uses 1.5 kWh for every hour it continuously draws that full power. A higher purchase price by itself does not change that arithmetic.

Features can still affect real-world use. A better thermostat, timer, lower-power modes, or controls that help you avoid unnecessary runtime may reduce total consumption. Compare the wattage and controls rather than assuming a premium heater must have a lower hourly electricity cost.

Do Oil-Filled Heaters Cost Less to Run?

An oil-filled electric radiator is still an electric resistance heater. If it and another heater both draw 1,500 watts continuously, their full-power electricity cost is essentially based on the same 1.5 kWh per hour. The oil acts as a heat-transfer and heat-storage medium; it does not create free energy.

Real-world costs can differ because heater controls, thermostat behavior, room conditions, and usage patterns determine how long each unit actually draws power.

Is a Space Heater Cheaper Than Central Heating?

There is no single answer for every home. A space heater can make sense when you only need to warm one occupied room and can reduce heating elsewhere. But using multiple 1,500-watt heaters for long periods can add substantial electricity use.

The comparison also depends on what your central system uses. A gas furnace, electric furnace, boiler, and heat pump have different fuel prices and efficiencies. Compare the cost of heating the space you actually need rather than assuming a portable heater is always cheaper.

How to Lower the Cost of Running a Space Heater

• Heat the occupied space, not the whole house unnecessarily. A space heater is most useful as targeted heat.
• Use the thermostat. Avoid setting the heater higher than needed.
• Use a lower-power setting when it keeps you comfortable. Lower wattage reduces electricity draw while that setting is active.
• Reduce obvious drafts. Close exterior doors and address easy-to-fix air leaks where appropriate.
• Turn the heater off when it is not needed. Runtime is one of the biggest variables in the cost equation.
• Use your own electricity rate. A national average is useful for examples, but your bill gives you a better estimate.

Space Heater Safety Matters

Cost is only part of the decision. The U.S. Consumer Product Safety Commission (CPSC) estimates that portable heaters, including electric space heaters, were involved in an average of 1,600 fires per year, with an average of 70 deaths and 150 injuries annually during 2020–2022.

• Keep portable heaters at least 3 feet from drapes, furniture, bedding, and other combustible materials.
• Plug an electric space heater directly into a wall outlet, not an extension cord or power strip.
• Turn the heater off when sleeping.
• Place it on a stable, level surface where it will not be knocked over.
• Follow the manufacturer’s instructions and warnings for your specific model.

These recommendations come from the CPSC’s January 2026 winter-heating safety guidance.

How Much Would a Space Heater Cost to Run for 24 Hours?

A 1,500-watt heater drawing full power continuously for 24 hours would use 36 kWh. At 18.31¢/kWh, that would cost about $6.59 for one day. Repeating that for 30 days would use 1,080 kWh and cost about $197.75.

Again, that is a mathematical continuous-runtime scenario, not a typical-use prediction. It shows why runtime matters so much when estimating the impact of a high-wattage heater on an electric bill. If your bill has already jumped and you are not sure the heater is the only cause, use our high electric bill troubleshooting guide.

The Bottom Line

For a typical 1,500-watt example, the calculation is straightforward: 1.5 kW × hours used × your electricity rate. At the July 2026 U.S. residential average of 18.31¢/kWh, continuous full-power operation costs about 27¢ an hour.

The most accurate estimate comes from replacing the national average with your own utility rate and being realistic about how long the heater’s heating element actually runs. That gives you a useful number for deciding whether targeted space heating makes sense in your home.

Sources

• U.S. Energy Information Administration — Electric Power Monthly, July 2026 residential electricity price (accessed October 4, 2026).
• U.S. Consumer Product Safety Commission — Keep Warm and Safe This Winter (January 23, 2026).

Use the main electricity cost calculator for other appliances and devices.