How Much Does It Cost to Run a Space Heater? (500W to 1,500W)

Space heaters are among the most power-hungry appliances you can plug into a socket, so a few hours a day adds up fast. Below: the cost for every common heater size, a calculator for your own rate, and the changes that cut the bill.

Space heater cost calculator

Enter your heater’s wattage and the price per kWh from your bill for the most accurate figure.

How much a space heater costs per hour, day and month

These figures assume the heater runs at full power the whole time. Heaters with a thermostat usually cost less in practice (see why yours may cost less).

Your local rate changes the answer a lot. In California, where homes paid about 33.6¢ per kWh in July 2026, a 1,500 W heater costs about 50¢ an hour; in Texas, at about 15.9¢, about 24¢. See electricity rates by state.

How we calculated these costs

Electricity is billed by the kilowatt-hour (kWh): one kWh is a 1,000 W appliance running for one hour. The cost of running a heater is:

Cost = heater power in kW × hours used × price per kWh

For a 1,500 W heater used for 8 hours: 1.5 kW × 8 h = 12 kWh. At 18.2¢ that is $2.18; at 26.32p it is £3.16. Our methodology explains where each rate comes from and when we update it.

Why your heater may cost less than this

A heater with a thermostat switches its element off once the room reaches the set temperature, then back on as the room cools. The table above is the maximum, with the element on all the time.

How much the heater cycles depends on the size of the room, insulation, the outside temperature and the setting you choose. A small, well-insulated room with the door closed costs far less than a draughty open-plan space.

Is a space heater cheaper than central heating?

Every electric space heater turns almost all of its electricity into heat, so a 1,500 W oil-filled radiator and a 1,500 W ceramic heater cost the same per hour. What changes the answer is what you compare it with:

• Heating one room versus the whole house. Running a heater in the room you use while turning the central heating down can save money. The US Department of Energy estimates that turning your thermostat back 7 to 10°F for 8 hours a day can save up to 10% a year on heating and cooling.
• Gas heating in the UK. Under the October to December 2026 price cap, gas costs 7.97p per kWh against 26.32p for electricity. Even allowing for boiler losses, heat from a gas boiler costs roughly a third as much per unit as heat from a plug-in heater, so heating a whole home with space heaters usually costs more.
• Heat pumps. A heat pump delivers around 2 to 4 units of heat for each unit of electricity, so it heats far more cheaply than any plug-in resistance heater.

If your winter bill has jumped, see why electric bills rise in winter.

How to cut the cost of running a space heater

1. Use the thermostat or the lowest setting that keeps you comfortable. A heater on 750 W costs half as much per hour as one on 1,500 W.
2. Close the door and block draughts. The smaller and better sealed the space, the less time the element stays on.
3. Heat the person, not the house. An electric blanket uses roughly 100 W, a fifteenth of a 1,500 W heater (see what an electric blanket costs to run).
4. Use a timer. Warm the room before you arrive instead of running the heater all evening.
5. Turn the central heating down while you zone-heat, otherwise you pay for both.
6. Check your tariff. If electricity is cheaper at night on your plan, a timer can shift use to those hours. More ideas: how to lower your electric bill.

Space heater safety

• Plug the heater directly into a wall outlet. Do not use an extension cord or a power strip.
• Keep it at least 3 feet (about 1 metre) from curtains, bedding, furniture and anything else that can burn.
• Choose a model with tip-over and overheat protection, certified by a recognised testing body.
• Switch it off when you leave the room or go to sleep, and never use it to dry clothes.

Frequently asked questions

Is it cheaper to leave a space heater on all night?

Running a 1,500 W heater at full power for 8 hours costs about $2.18 in the US and £3.16 in the UK. A thermostat or a lower setting cuts that, but an electric blanket keeps you warm in bed for a fraction of the cost. Most manufacturers advise against leaving heaters on while you sleep.

Do space heaters use a lot of electricity?

Yes. At 1,500 W, one hour uses 1.5 kWh, about what a typical modern refrigerator uses in a whole day.

How many amps does a 1,500 W space heater draw?

About 12.5 amps on a US 120-volt circuit and about 6.5 amps on a UK 230-volt circuit. On a standard 15-amp US circuit that leaves little room for anything else.

Is an oil-filled radiator cheaper to run than a ceramic heater?

Not per hour at the same wattage. An oil-filled radiator holds heat and releases it slowly, so in a closed room its thermostat may switch the element on less often, which can lower the real cost.

What size space heater do I need?

A common rule of thumb is about 10 watts per square foot (around 100 watts per square metre) for a room with average insulation, so a 1,500 W heater suits roughly 150 square feet (about 14 square metres).

A real example: heating a home office all winter

Take a 1,500 W ceramic heater in a 12 ft by 12 ft home office, used 5 hours a day on workdays and weekends. At full power that is 225 kWh a month, about $40.95 in the US or £59.22 in the UK.

With the thermostat set to 68°F (20°C) in a reasonably insulated room, a heater like this typically runs about 60% of the time once the room is warm. That brings it down to roughly 135 kWh a month: about $24.57 or £35.53. Over a five-month heating season, the difference between leaving it on full and letting the thermostat work is around $81.90 in the US.

If the rest of the house can stay a few degrees cooler while you work, this is one of the few cases where a space heater can genuinely save money.

Mistakes that make a space heater expensive

• Heating a room with the door open. The heater ends up warming the hallway and runs flat out.
• Using it to replace central heating everywhere. Several 1,500 W heaters in several rooms quickly cost more than a heat pump or gas furnace.
• Ignoring the thermostat. Many cheap heaters only have high and low settings, so they never switch off. A model with a real thermostat pays for itself.
• Buying a bigger wattage than the room needs. A rough guide is 10 watts per square foot of floor area. A 100 sq ft room rarely needs more than 1,000 W.
• Running it overnight in an empty room. A timer or smart plug costs a few dollars and stops this.

More questions readers ask

Does a space heater raise my electric bill a lot?

It can. One 1,500 W heater used 8 hours a day for a month adds about 360 kWh, which is around 40% of an average US household’s monthly use. At 18.2¢ per kWh that is roughly $65.52 on top of your normal bill.

Are “energy-efficient” space heaters cheaper to run?

All plug-in electric resistance heaters turn electricity into heat at almost exactly the same rate: 1 kWh of electricity gives 1 kWh of heat. A model can save money only by heating for less time, through a better thermostat, a timer or by heating just the space you are using.

Is it safe to plug a space heater into an extension cord?

No. Heaters draw a lot of current for hours at a time, and most extension cords and power strips are not rated for it. Plug the heater directly into a wall outlet.

Sources

• U.S. Energy Information Administration, Short-Term Energy Outlook, and Electric Power Monthly (state prices).
• Ofgem, Energy price cap.
• U.S. Department of Energy, Programmable thermostats.
• Our own calculations, as described in our methodology.