How Much Electricity Does a Space Heater Use?

Want to learn how much electricity your space heater uses, and what it costs to run?

Maybe you’re already running a space heater and wondering if it is the source of your high electricity bills.

Or, maybe you’re considering buying one and want to know if it’s going to be expensive to run before making the investment.

If any of these sound like you, you’re in the right place!

In this proHVACinfo guide, you’ll learn:

  • What factors impact the cost of running a space heater? (you won’t forget this one trick!)
  • How you can estimate the approximate cost of running your space heater monthly, weekly, or even hourly?
  • Points to consider when shopping for a space heater (be sure to remember these when sizing a heater)
  • And much more!
proHVACinfo | How Much Electricity Does a Space Heater Use?

An average monthly energy bill in the US is estimated to be around $118, meaning that most Americans will spend in excess of $1400 annually on electricity!

This is a big chunk of most families’ budget, so understanding the impact a space heater will have on this is a good idea.

The good news? We’ve done the hard work to how you that running these appliances isn’t likely to cause a significant increase to your monthly bill!

What you need to know about how much electricity a space heater uses

Determining how much electricity your space heater uses (and how much it will cost you to run) is as simple as:

  1. Finding out how much your pay for electricity
  2. Looking for how much electricity your space heater uses and
  3. Determining how much that will cost you per hour, week, month, or year!

The way electricity is billed varies across the country, but the vast majority of suppliers bill in by what’s known as cents per kilowatt hour (usually abbreviated as “kWh”).

Knowing how much your electricity provider is charging in this format is key to calculating the cost of running a space heater.

Basically, a kilowatt hour is a measure of how much power your space heater draws every hour.

Interested in learning more? Check out this video!

Don’t worry, most homeowners have no idea how much they’re paying per kilowatt hour. If you aren’t sure, we’ll show you how to find out!

How Much Electricity Does a Space Heater Use?

As mentioned above, in addition to the price of the electricity in your home, you’ll also need to know how much power your space heater draws while it’s running.

This is represented as wattage.

Wattage tells you how much electricity your space heater uses every hour.

Fortunately, wattage is one of the more prominent figures advertised on space heaters.

You can almost always find it on a label on space heater itself, normally out of easy view like on the back near the power cord or on the bottom.

Most residential space heaters are 1500 watts, 750 watts, or they have the ability to switch between 1500 and 750 watt modes.

Of course, this varies between makes and models, so be sure to read the information on the device for the best information.

What Size Space Heater Do I Need?

This is another very common question when it comes to space heaters.

Fortunately, there’s a simple answer, and it’s something called the 10-watt rule.

The idea here is that for every square foot you want to heat, you need 10 watts of power.

So, a 1500-watt space heater is effective in heating 150 square feet!

Here are a few benchmarks for common household rooms to put that in context:

  • Bathroom, small – 45 square feet
  • Bathroom, average – 60 square feet
  • Bathroom, large – 80 square feet
  • Living room, average – 330 square feet
  • Kitchen, average- 150 square feet
  • Bedroom, small (guest room) – 70 square feet
  • Bedroom, Master – 170 square feet
  • Garage, 1 car – 260 square feet
  • Garage, 2 car – 400 square feet

Keep in mind these are just estimates.

Determining the actual square footage of the room you want to heat is easy!

Just grab a tape measurer, measure the width of the room and the length, and multiply.

One thing that often goes overlooked is the height of the room’s ceilings! Most estimates you come across assume a standard ceiling height of about 8 feet, so if the room you want to heat has especially high ceilings, you may want to increase the wattage on your heater.

For example, a room that is 10 feet wide and 12 feet long is 10 x 12 = 120 square feet!

proHVACinfo | 10-watt rule

Supplies You’ll Need to Determine the Monthly Cost of Your Space Heater

  1. Your latest power bill – The cost per kWh should be listed on the bill breakdown. If you don’t have any recent bills, we can still help you to fashion a decent guess – keep reading to find out how!
  1. Your space heater – The product information label on the back of the device, usually on the bottom or near where the cord meets the appliance, will tell you the wattage of the heater.
  1. An idea of how often you run (or plan to run) your space heater.
  1. Finally, a calculator. The one built into your cell phone will work just fine.

Step 1 – Establish Your Monthly Electricity Costs

Of course, using your most recent bill from your energy provider will yield the most accurate information.

If you don’t have access to the latest, an older bill should still tell you what the kWh cost is.

Keep in mind, you’re looking for the number next to ¢/kWh

If you can’t find any bills, you should still be able to roughly estimate the cost of electricity in your state by referring to this page on the website of the US Energy Information Administration.

It provides a state by state breakdown of the average price of electricity across the nation. Make sure you’re using the residential table for the most accurate estimate.

proHVACinfo | DYK Electric Bill

Step 2 – Determine the Wattage of Your Space Heater

Look at the back or the bottom of your space heater, on there you should see a label affixed with some electrical information.

On that label there should be information as to the wattage of the appliance.

In the event that there is no electrical label, or that it is illegible, or simply doesn’t show the wattage, you may also find that information on the product box/packaging, or even more likely, in the instruction manual.

If you purchased the device from Amazon, try typing in the make and model into the search bar, and there’s a good chance the wattage is listed there, too.

Google is also a helpful tool when searching for this info.

proHVACinfo | Did You Know Space Heater

Step 3 – Estimate How Often Your Space Heater Runs

To make this calculation accurately, it’s very important to have a good idea of how long you’re running your space heater on a daily basis.

Are you running your space heater on a timer to warm up a room before you come home?

Perhaps you’re using it all day to keep your basement or garage above freezing?

Understanding the number of hours it runs for will make it much easier to get a true understanding of the cost of running your space heater.

Step 4 – Calculate the Hourly Expense of Running the Space Heater

If you’ve completed steps 1 through 3 you should know how many cents per kWh your electricity provider charges you.

You should also know both how much energy your space heater draws, and how long you run it for each day.

It’s important to understand the distinction between watts and kilowatts.

1 kw is 1000 watts, so, because your electricity is billed in kWh, you will need to divide the wattage on your space heater by 1000 to convert watts to kilowatts.

As we mentioned earlier on, most space heaters draw 1500 watts, so that’s the figure we will use for this example.

So, 1500 divided by 1000 gives us 1.5 kw. Next, to calculate kWh we need to multiply our energy draw in kw by the number of hours it runs for.

For simplicity we will say 10 hours – 1.5 x 10 = 15 kWh.

Next, we will calculate the cost.

We should know from our latest bill, or from using the average value from the table provided by the US Energy Information Administration, how much we pay in ¢/kWh.

In New York, the average for January of 2021 was 18.27¢/kWh.

To calculate the cost, we take the energy used, and multiply it by the cost to run per hour. Therefore 15 kWh x 18.27 = 274.05 cents, or about $2.75.

In summary, this means running this 1500 watt space heater for 10 hours per day in New York will add approximately $2.75 per day to your electricity bill, or a little over $80 per month.

Of course, these numbers will vary based upon actual use conditions, the various eco-modes available on space heaters, the actual cost from your electricity supplier, and of course, taxes and fees.

Factors That Influence the Running Cost of a Space Heater

Space heaters differ from appliances like air conditioners in that they don’t always feature a thermostat. In many cases it’s simply a case of off, or on!

In the event that your space heater has 2 or more heat settings, this will likely drop the wattage used, in some cases by 50% or more.

For example, if your space heater has both 1500 and 750 watt settings, using the 750 watt setting will cut the cost of running the appliance in half when used for the same amount of time.

If your space heater has a dial control over the heat output, the greater the temperature you set, the higher the power draw.

These heaters are a little more difficult to calculate running costs exactly (if they aren’t being used at 100% at all times, that is), but if you have a rough idea of how often you use each setting, you should be able to determine a good estimate.

Now, even if your space heater has an automatic thermostat, there are of course some external factors that will influence the cost of running.

Air Temperature Outside

The colder it is outside, the colder it’s likely to be in your home without the heater running.

The colder it gets inside, the harder your space heater will need to work to reach the desired temperature.

Quality of Your Home Insulation

Depending on how well the room in which the heater is placed is insulated, you could be losing a lot of the heat that you’re paying good money to provide.

Spray foam insulation is the gold standard when it comes to heat retention, but any insulation is better than none.

Also be aware that windows and doors also provide an easy path for heat loss.

Keep curtains closed, install weather sealing around the windows, and buy a draft excluder for the base of your door to prevent unwanted loss of heat and to keep those bills down.

Room Dimensions

A bigger room means more air to heat.

If your space heater is running on a programmable thermostat to reach a desired temperature, the greater the volume of the space, the longer it will take to heat, and therefore the more it will cost to run.

This handy guide from the US Department of Energy provides some excellent money saving tips when it comes to heating your home.

Final Thoughts

We hope that this guide to calculating the cost of running a space heater has been useful for you.

In the event that you don’t want to break out the calculator, this handy energy cost calculating tool will do the work for you using the latest averages in every state.

Stephen Marks

Stephen Marks

Stephen is an HVAC and home-repair enthusiast. He's here to answer any of your questions about HVAC!

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Stephen Marks

Stephen Marks

Stephen is an HVAC and home-repair enthusiast. He's here to answer any of your questions about HVAC!

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