A typical 1,500-watt electric space heater costs about 27 cents per hour to run on its high setting at today’s average US electricity price, and roughly half that on a 750-watt low setting. Run it eight hours a day for a month and you’re looking at around $65. Whether that saves you money depends on one thing: whether you turn the rest of the house’s heat down while you use it.

Quick answer

Setting / scenario	Power	Energy used	Cost at ~$0.18/kWh
High, 1 hour	1,500 W	1.5 kWh	~$0.27
Low, 1 hour	750 W	0.75 kWh	~$0.14
High, 8 hours	1,500 W	12 kWh	~$2.16
High, 8 h/day for 30 days	1,500 W	360 kWh	~$64.80
Low, 8 h/day for 30 days	750 W	180 kWh	~$32.40

These are maximum costs. A heater with a thermostat cycles off once the room is warm, so real-world costs are often lower. Savings vary by climate, home and rates.

How to calculate your own space heater cost

You only need three numbers: the heater’s wattage, how long it runs, and what you pay per kilowatt-hour (kWh).

Cost per hour = watts ÷ 1,000 × your price per kWh

According to the U.S. Energy Information Administration (EIA), the average US residential electricity price is roughly 18 cents per kWh in 2026. That’s the figure used throughout this article. So:

• 1,500 W heater: 1,500 ÷ 1,000 = 1.5 kWh per hour × $0.18 = $0.27 per hour
• 1,000 W heater: 1.0 kWh × $0.18 = $0.18 per hour
• 750 W setting: 0.75 kWh × $0.18 = $0.135 per hour (about 14 cents)

Where to find the wattage

Look on the label on the back or bottom of the heater, or in the manual. Most plug-in space heaters sold in the US top out at 1,500 watts, because that’s about as much as a standard 120-volt household circuit can comfortably supply to one device. Many have a low setting around 600–900 watts.

Where to find your electricity price

Your price is on your bill. Divide the total charge (not counting fixed monthly fees) by the kWh you used to get your real, all-in rate. Our guide on how to read your electric bill walks through it line by line.

Cost per hour at different electricity rates

Electricity prices vary a lot by state and utility, from around 11–12 cents per kWh in some of the cheapest states to over 30 cents in the most expensive ones. Here’s what a 1,500 W heater costs at different rates:

Your rate	Per hour (1,500 W)	8 h/day, 30 days
$0.12/kWh	$0.18	$43.20
$0.18/kWh (≈ US average)	$0.27	$64.80
$0.25/kWh	$0.38	$90.00
$0.32/kWh	$0.48	$115.20

The math for the monthly column: 1.5 kWh × 8 hours × 30 days = 360 kWh, multiplied by the rate.

If you’re on a time-of-use plan, the hour matters too. Running a heater during an evening peak can cost noticeably more than the same hour late at night. See time-of-use electricity rates explained to check your plan’s peak window.

Why real costs are usually lower than the maximum

The tables above assume the heater runs flat out the whole time. In practice:

• Thermostats cycle the heater. Once the room reaches the set temperature, the heating element switches off and on to hold it. In a small, reasonably well-insulated room, it may run only part of each hour.
• Eco or auto modes lower the power when the room is close to target.
• Room size and drafts matter. A heater in a drafty room with single-pane windows will run much longer than the same heater in a snug bedroom.

A simple way to know your real cost is a plug-in electricity usage meter (often called a kill-a-watt style meter). Plug the heater into it for a few days and it will show the exact kWh used. Then multiply by your rate.

Do “energy-efficient” space heaters cost less to run?

Mostly, no. Here’s the key fact: every electric resistance heater turns essentially all the electricity it uses into heat. A 1,500 W ceramic heater, a 1,500 W oil-filled radiator and a 1,500 W fan heater all produce the same amount of heat per hour and cost the same per hour at full power.

What differs is how they deliver that heat:

• Fan / ceramic heaters warm the air quickly. Good for short bursts in a room you just walked into.
• Oil-filled radiators heat up slowly but keep radiating after they cycle off. Good for steady, quiet heat in a bedroom.
• Infrared / radiant heaters warm people and objects in front of them rather than the air. Good for a desk or a drafty spot where heating the whole room is wasteful.

A heater can save you money by heating less, with a good thermostat, a timer or a lower setting, but not by making more heat from the same watts. Be skeptical of any ad claiming a small plug-in heater will slash your whole heating bill.

Space heater vs central heating: which is cheaper?

Per unit of heat, electric resistance heat is one of the more expensive ways to warm a home. Here’s a rough comparison for 100,000 BTU of delivered heat (1 kWh = 3,412 BTU; 1 therm of gas = 100,000 BTU):

Heat source	Math	Cost for 100,000 BTU
Electric space heater	29.3 kWh × $0.18	~$5.28
Gas furnace, 95% efficient	1.05 therms × ~$1.50	~$1.58
Gas furnace, 80% efficient	1.25 therms × ~$1.50	~$1.88
Heat pump (efficiency ~2.5–3×)	9.8–11.7 kWh × $0.18	~$1.76–$2.11

The natural gas price here (about $1.50 per therm) is based on EIA’s 2025 average residential price of roughly $15 per thousand cubic feet. Heat pump efficiency drops in very cold weather, so real results vary. For a deeper comparison of whole-home systems, see heat pump vs furnace cost.

So when does a space heater save money? Only when it lets you heat less space:

• You spend most of the evening in one room and turn the central thermostat down several degrees.
• You need a little extra warmth in a home office during the day while the rest of the house is empty.
• One cold room (a converted garage, a basement den) would otherwise force you to crank the whole house.

When it doesn’t: if you leave the central heat where it was and add a space heater on top, you’re simply paying for extra heat.

A worked example

Say your gas furnace keeps the house at 70°F (21°C). In the evening you sit in the living room for five hours, so you turn the thermostat down to 64°F and run a 1,500 W heater at an average of 60% of full power:

• Heater: 1.5 kWh × 0.6 × 5 h = 4.5 kWh × $0.18 = $0.81 per evening
• Furnace savings: depends on your home and climate, and you’d need your own gas usage to measure it

Whether you come out ahead depends on the size of your house and how efficient the furnace is. In a larger home with gas heat, zone heating one room often wins. In a small apartment with a heat pump, it often doesn’t. Our guide on how to save on heating this winter covers other ways to trim the bill.

Tips to cut your space heater costs

• Use the thermostat, not just “high.” Set it to the lowest comfortable temperature and let it cycle.
• Use a timer so it isn’t running in an empty room.
• Heat the person, not the room. A radiant heater aimed at your chair or desk can keep you comfortable on a lower setting.
• Close the door of the room you’re heating.
• Seal drafts around windows and doors with weatherstripping or a draft stopper.
• Size it right. An oversized heater in a tiny room will cycle a lot; an undersized one will run constantly.
• Don’t run it overnight as a habit. It’s both a cost and a safety issue.

Safety basics (please don’t skip)

The U.S. Consumer Product Safety Commission (CPSC) recommends:

• Keep space heaters at least three feet away from anything that can burn, such as curtains, furniture and bedding.
• Plug electric heaters directly into a wall outlet, never into an extension cord or power strip.
• Never leave a heater running while you sleep.

Also look for a heater with tip-over protection and overheat shut-off, and a safety certification mark from a recognized testing lab.

Frequently Asked Questions

How much does it cost to run a space heater all night?

For eight hours on high (1,500 W) at about $0.18/kWh: 1.5 × 8 × $0.18 = about $2.16. However, safety agencies advise against leaving a space heater on while you sleep. Warm the room before bed, then switch it off.

Is it cheaper to run a space heater or the furnace?

Per unit of heat, a gas furnace or heat pump is usually cheaper. A space heater only saves money if you use it to heat one room and turn the central heat down.

Do space heaters use a lot of electricity?

Yes, for a single appliance. At 1,500 W, a space heater draws more power than most things in your home. Run it for hours every day and it can add a noticeable amount to your monthly bill.

Does the low setting really cost half as much?

Roughly, yes. If the low setting is 750 W, it uses half the energy per hour of the 1,500 W high setting. But it also makes half the heat, so it may need to run longer to warm the room.

Are oil-filled heaters cheaper to run than ceramic ones?

At the same wattage, no. They use the same electricity per hour. Oil-filled models hold heat longer after cycling off, which some people find more comfortable, but the cost per hour at full power is identical.

The bottom line

A standard 1,500 W space heater costs about 27 cents an hour at average US electricity prices, around $2 for an eight-hour stretch, and roughly $65 a month with heavy daily use. It’s a smart tool for heating one room while you turn the rest of the house down, and an expensive one if you use it on top of central heat. Check your own rate, use the thermostat and a timer, follow basic safety rules, and a space heater can keep you comfortable without an ugly surprise on your bill. Savings vary by climate, home and rates.

Figures in this guide are estimates based on typical US prices at the time of writing. Savings vary by home, climate and utility rates — check your own bill before making a purchase.