How Much Electricity Does a Space Heater Use? Wattage and Cost per Hour

A space heater is a wonderful thing to have on a cold day, and a good one will heat up a small space with delightful effectiveness.

But are space heaters efficient as well as effective? How much electricity does a space heater use, and how much does it actually cost to run one?

Let’s look at these questions in a bit more detail, and also look at some ways to make your space heater more efficient and less expensive to use, in this guide to how much electricity space heaters use.

Executive Summary:

• A 1,500-watt space heater costs about 27 cents an hour to run, based on the U.S. Energy Information Administration’s July 2026 national average residential price of 18.31 cents per kWh
• The cost of running a space heater can vary considerably depending on where in the US you are, and what time of day you are running it
• For a more accurate calculation, you can use a simple formula (as detailed below) to determine the space heater’s kWh (kilowatt hour) consumption and consult your local utility company for current rates per kWh.
• While the hourly rate may seem low, it can quickly add up, and space heaters, if used too much or unwisely, can be fairly expensive
• There are several ways to use a space heater more efficiently and less expensively, as outlined below

Does An Electric Space Heater Use a Lot of Electricity?

Space heaters can be very effective at quickly heating smaller spaces, and are a great thing to have to supplement your home’s central heating system, but in fact, they are not the cheapest way to heat, and if used too much can end up being expensive.

Specifically, most portable space heaters top out at 1,500 watts, which is about what a standard 15-amp household circuit can carry, according to the Consumer Product Safety Commission. Different models may use less on their lower settings.

Ok, great, but what does that really mean? After all, you might not really be wondering how much electricity a space heater uses, but instead just how much it costs to run a space heater.

How Much Does a Space Heater Cost to Use?

If we assume the average of 1,500 watts of power, we can quite easily convert this into kWh, or kilowatt hours, which is the unit your utility company uses to determine your electric bill.

Energy Usage (in watts) multiplied by time (in hours) and divided by 1,000 -equals- kWh (kilowatt hours)

So if you use a space heater for, say, two hours, we can simply multiply the heater’s electrical rating – 1,500 watts – by 2 (hours), giving us 3,000 watts. Then we divide this by 1,000 to arrive at the correct kWh or kilowatt hours figure: 3,000 / 1,000 equals 3-kilowatt hours.

A kilowatt hour costs about 18.31 cents, based on the U.S. Energy Information Administration’s July 2026 national average for residential customers, so your two hours of toastiness will cost you about 55 cents (3 kWh x 18.31 cents).

Here is what common heater wattages cost to run at 18.31 cents per kWh (EIA, July 2026). The formula is watts x hours / 1000 x price per kWh, so a 1,500-watt heater costs 1.5 x 18.31 = 27.5 cents an hour.

Heater wattage	Cost per hour	8 hours a day	8 hours a day for 30 days
500 watts	9.2 cents	$0.73	$21.97
750 watts	13.7 cents	$1.10	$32.96
1,000 watts	18.3 cents	$1.46	$43.94
1,500 watts	27.5 cents	$2.20	$65.92

If we go on to calculate a monthly cost for your electric space heater, based on two hours of use a day, it would cost about $16.50 a month (3 kWh x 30 days x 18.31 cents). Of course, many people use their space heaters far more than this, and their costs during cold months can be significantly higher.

• Keep in mind that all of this is based on a national average, and the price of a kilowatt hour will vary dramatically in different states and different parts of the country and also vary at different times of the day.

You can use the above formula to determine the exact kWh consumption and then consult your local utility company for their specific price for a kilowatt hour of electricity to make more exact and useful calculations.

So, Are Space Heaters Expensive to Run?

This is a good question, and a bit of a tricky one as well – see, the hourly cost of running a space heater can be quite small, or at least seem quite small – about 27 cents an hour for a 1,500-watt heater, but in fact, this can really add up over time.

And so a space heater, if used too much or unwisely, can actually end up being pretty expensive, and it adds up fast: a 1,500-watt heater running 8 hours a day for 30 days uses 360 kWh and costs about $66 a month at 18.31 cents per kWh.

Central heating is usually less expensive for a whole home, but a combination of space heater and central heat can be the best, and most cost-effective, approach, and of course, a space heater might make a lot more sense if you are only heating a very small area.

How Can You Save Money with a Space Heater?

If you use a space heater a lot, it can indeed become a very expensive appliance, but there are a few basic things you can keep in mind and do to keep costs down and heat your home, yourself, and your family, as effectively and efficiently as possible.

Use Space Heaters and Central Heating in Concert

It makes great sense to only heat the rooms that are being occupied, so you can turn off the central heat in unused rooms, and turn it down overall, to save money. Then, by using space heaters judiciously for small areas, just when you are there and need them, you can end up significantly reducing energy bills.

Don’t Use A Space Heater to Heat a Large Room

Space heaters are great for small areas, and are especially effective in closed spaces like bedrooms or offices, but have to work too hard to warm up larger areas, and will end up being an expensive solution – better to use central heat for large spaces.

Never Heat Unused Rooms

This also applies to central heat or any heating system but is particularly true for space heaters, which cost more per unit of heat than most central heating, especially in larger rooms.

Use a Separate Thermometer

Space heaters will often have built-in thermostats, which will monitor temperature and even turn the unit off when a desired temperature is reached. These inbuilt thermostats can be inaccurate, though, and it is better to use a physically separate thermometer and turn the heater down or off when appropriate.

Do Space Heaters Use a Lot of Electricity?

We’ve looked at this very question in some detail above, but to sum it up, yes and no…

Used on a limited basis – for a short time and in an appropriately small space – space heaters can be affordable, efficient, and very effective, and they can be a great supplement to central air, and if used smartly in this way can save you money.

But if you try to use space heaters as a primary heating source, especially for long periods, or in too large or open of spaces, they can end up being quite expensive to run, and central heat is almost always a better solution – more effective and efficient and less expensive.

By following a few basic guidelines, as detailed just above, you can keep a space heater affordable to use. For safety, plug it straight into a wall outlet (never an extension cord or power strip), keep it at least three feet from anything that can burn, and never leave it on while you sleep.