Enter the number of usage hours, power setting (in wattage) of electric space and click on calculate button to know power consumption along with running cost per hour, day, week and for a year.

How Many Watts Does An Electric Space Heater Use?

An electric space heater uses approximately 100 watts, on an average, an electric space heater is used approximately 5 hours a day.

Click calculate to find the energy consumption of a space heater using 1500 Watts for 5 hours a day @ $0.12 per kWh.

*Based on $0.12/kWh electricity cost and 5 hours daily usage. Actual energy consumption and cost may vary. For information and to compare models, visit https://www.eia.gov.

*The figures in this table are approximate. The actual power consumption of your household appliances may vary significantly from the figures in this chart. Before you do a final load calculation for your household, we strongly recommend checking the tags and owners manuals for your appliances to get precise figures.

With the promise of high efficiency and portability, space heaters have become the preferred heating device for most families worldwide to brave the icy claws of winter.

But like all electrical equipment, you must factor in the amount power needed to keep your space heater up and running at its optimal capacity.

Electricity Usage Of A Space Heater

Space heaters are portable electric devices used for heating up a single room or an area of the house.

Convection space heaters heat up a room by heating up the air, most common convection space heaters will use around 1500 watts.

The last thing you would like to see is a monstrous peak in your electricity bill, or worse, an overheated and broken space heater stemming from overuse.

What Is The Average Power Of A Normal Space Heater?

Most temperate climates around the world require the usage of some form of heating to stave off the frigid chill of the northern winds, including countries scattered across certain parts of Europe and Asia.

Thus, many have resorted to using space heaters to keep themselves and their loved ones warm and comfortable.

Space heaters, with the exception of gas heaters and kerosene heaters, mainly operate on electricity.

The electric space heaters tested approximately use 1,500 watts to fully power.

According to a survey conducted by the United States Department of Energy, the amount of power consumed by a standard space heater in a typical American household ranges between 5,000 kW and 30,000 kW per annum.

This amounts to a rough estimate of between $1,200 to as much as $6,000 of heating bills spent on a yearly basis.

However, this number excludes the inclusion of taxes or additional fees that might be applicable to your location.

How Do I Determine The Amount Of Energy Used By My Space Heater?

In order to ascertain the amount of energy consumed by your space heater, you must first understand the concept of heater wattage.

All electrical heaters contain two separate wattage ratings. The first is power consumption, whilst the second pertains to the heating capacity of your space heater.

These two tit-bits of information are usually found in the manual or booklet that comes with your heater, or is printed on the heater itself.

In the case of heater wattage, the advertised rating usually pertains to the power output of the space heater, and not its direct power consumption.

How To Estimate Power Consumption?

If you wish to discover the actual power consumption of the space heater that you have obtained, you must first take a quick peek at the label located at the bottom or the back of your heater.

The electrical ratings will usually be stamped on the label itself, in terms of either Watts (W) or Voltage (V) and Amperage (A).

You can then determine the heater wattage using a simple formula of:

Watts (W) = Volts (V) x Amps (A) x Power Factor.

In most cases, the Power Factor is a standard of 1 unit, but there are always exceptions to this rule. If you wish to determine the efficiency of your space heater, you can use the equation listed below:

x 100 =  %

The percentage (%) resulting from the equation is also known as the power input of the space heater in terms of heat. For example, if your space heater has a label with the designated numbers of 120VAC and 15A, this means that:

120V x 15A x 1 = 1800 Watts or 1.8 kW

What Is A Space Heater Power Rating?

Now that you have figured out how much power your space heater uses in terms of wattage (W), the next step would be to determine your heater power rating so that you can have a rough estimate of your heating bill.

In general, a space heater that utilizes either 120V or 240V to run will more or less consume the same amount of energy, and therefore generate heating bills that are not too disparate from each other.

If you have gas central heating then this will be a lot cheaper to run than an electric heater considering the power consumption.

Heating bills also directly translate into electricity bills. Each electricity bill is measured in kilowatt hours (kWh).

In other words, the electricity bill is determined by the amount of energy used by a 1-kilowatt heating device for an hour.

In order to ascertain how much a 1.8 kW space heater will cost you, you may use this simple equation of:

No. of Watts used by your space heater x No. of hours the heater is used

For example, if you wish to watch your favorite sports program on television for two hours in a row, and you leave your space heater turned on to retain the warmth in your living room:

1,800 Watts x 2 hours = 3,600

Next, divide the number you have attained by 1000:

= 3.6

Use the resultant number and multiply it with the utility charges for electricity designated to your region.

Since these charges vary from location to location, do take note that using the same space heater in different areas may grant you different overall charges.

So, if the local utility charges for electricity costs $0.75, for example, then:

3.6 x $0.75 = $2.70

This means that the heating bills for those two hours of luxurious warmth in your living room has just cost you a whooping total of $27.90.

If you use the same space heater for the same amount of time for the whole month, your monthly electricity bill from your space heater alone will shoot up to:

$2.70 x 30 days = $81.00

Remember, this is without factoring in the cost of taxes or any other additional fees!

The longer you turn on your space heater, the higher that little spike in your electricity bill will be.

This is why the United States Department of Energy has ascertained that bills stemming from heating devices amount to as much as 40% of overall household energy consumption in North American homes.

What Is The Electricity Consumption Of My Space Heater?

The power consumption of your space heater is different compared to its power rating.

Unlike the heater wattage rating, which is measured in kilowatts (kW), the power consumption is measured mostly in BTUs (although this can be measured in Watts (W) and Amperages (A) too).

A BTU is known as a British Thermal Unit.

It is extremely useful in determining the energy output of a space heater since some heaters have multiple or different power levels, as well as different heat settings.

BTUs are capable of ascertaining the heating capacity of not only electric-based space heaters such as ceramic heaters, but can also calculate the thermal energy output of heaters that use fuel such as kerosene, paraffin or gas heaters.

Additionally, it can also determine the capacity of cooling systems.

In most cases, the BTU of a space heater will be listed on the label on the heater itself.

But in the event that it is nowhere to be found, you may manually calculate the BTU of your space heater using this basic formula of:

Heater Wattage Rating (W) x 3.413 = BTU Output

3.413 is the amount of BTU that is equal to 1 Watt of energy, and therefore a standard in this circumstance.

Thus, a heater with a 1,800 W heater wattage rating would be: 1,800 W x 3.413 = 6143 BTU

This means that a 1,800 W space heater is capable of delivering 6143 BTU of heat, and a larger space heater of 5,000 W will deliver at least 17,065 BTU of heat.

Thus, a heater with a higher BTU rating would generally have greater power consumption.

Will A Larger Space Heater Consume More Electricity?

Technically, yes. There are many factors that contribute to the power consumption of a space heater – from energy efficiency to shape, weight and design.

But the most notable factor is the size of the space heater itself.

Over the course of the next few lines, we shall explore the power consumption of a space heater according to its size and its relevant heating capacity:

  • 2557 BTU Heaters

A space heater with 2557 BTUs is sufficient enough to heat up a 100 square feet room or office space. The wattage required to run a heater of this size is approximately 750 W.

  • 6820 BTU Heaters

Space heaters with 6820 BTUs require at least 2000 W to run. They are also capable of heating up an enclosed space of up to 250 square feet.

  • 13640 BTU Heaters

An even larger space heater of 13640 BTUs needs approximately 4000 W to operate.

A heater of this size can provide warmth in a larger room or space such as a parking garage or hall of up to 450 square feet.

Therefore, the larger the heater, the higher the amount of power required to operate the heater in concern.

With more Watts consumed, more warmth is provided per square feet, and more heating units are allocated for each electrical unit that is being consumed.

In other words, the heater wattage is significantly increased.

Likewise, the size of the space heater increases as well, since a larger device would be needed to generate a larger amount of thermal energy to radiate additional warmth at a larger radius.

With the increase in power consumption, naturally, you will observe a staggering increase in your electricity bill.

Although heating costs vary from region to region as discussed earlier, the acceptable standard electricity rate in the US hovers around an average of $0.12 kW per hour.

Infrared heat is safer than conventional, resistive heat, but it takes just as much electricity to produce it.

If a heater with a 9000 BTU, for example, was run continuously for six hours a day, it would generate an overall cost of $0.52 daily. The monthly bill will then chalk up to $15.60.

Although this might not seem too much at first, once you take into account the additional cost of running a fan heater, you will need to multiply that value by three.

This will then elevate the total heating cost to $46.80.

Do Different Brands Of Heaters Consume Power Differently?

Simply put, yes. Each brand of the heater has been exclusively designed to have an output of different units of heat per unit of power consumed.

  • Depending on the type of heater being used (fan heaters, heat pumps or even radiators), the amount of space that can be warmed up varies as well, even if the same number of BTUs is being used.
  • Therefore, you must select your heater according to the size of the space you need to keep warm, and your own personal financial capacity.
  • Make sure you take your time to evaluate and study each heater at the store thoroughly and do take note of all their built-in safety features.
  • In most cases, the specifications of each heater including the Wattage (W), Voltage (V) and Amperage (A) as well as BTUs will be listed.

It is, therefore, your responsibility to select the most appropriate heater that will benefit your home or office in the best of ways.

What Are The Most Efficient Heaters That Consume Less Power?

There are three main types of heaters that have been noted to consume power at an efficient rate:

  • Fan Heaters

This type of space heater provides less than 1 unit of heat per unit of power consumed. This is because the fan within the heater itself consumes additional power.

  • Heat Pumps

Space heaters that utilize heat pumps are highly efficient with a consumption of up to 3 units or more of heat per unit of power consumed.

Heat pump-based heaters are therefore much larger and usually far less portable, but due to their strength and heating capacity, they are able to put out enough thermal energy to warm up a larger, enclosed space.

  • Radiators

Radiator-based space heaters are usually highly portable. They exude 1 unit of heat for each unit of power consumed, but are highly old-fashioned and can be hot to the touch.

Despite this, they do remain highly popular in some countries such as the UK and Russia.

Other Types Of Heaters And Power Consumption

There are other heaters such as natural gas heaters that use gases to function as well.

However, electricity-based heaters still remain highly sought after since they convert almost 100% of the electricity flowing through them directly into heat.

Heat pumps are an exception to this rule since they produce triple the output of heat.

This means for every 1000 Watts of electricity that is consumed, they can generate up to 3000 Watts of heat, which make them highly efficient, and the ideal choice for heating a home or office for most people in the US.


Thus, the power consumption of space heaters is largely dependent on several key factors, such as the size and heating capacity of each individual heater as mentioned above.

However, different types of heaters also contribute to the efficiency, power consumption and heat output of each space heater.

Therefore, the next time you flick out that credit card to go space heater shopping, it is best that you read through the specifications of each brand and type of heater first, and draw your own personal comparisons and conclusions.

Ultimately, it is up to you to decide which space heater to bring home and keep those fingers and toes warm and comfy throughout the day.