How To Size A Space Heater For Your Home

HomeHome Improvement

  • Author Albert Lee
  • Published August 24, 2020
  • Word count 595

Did you know that heating accounts for 42% of your home utility bill on average? That is a huge sum of money that you can save on if you are able to use your energy wisely and efficiently to heat up your house.

An easy way to save on heating costs is to use space heaters instead of the central heating system when you just intend to heat up part of the house. However, space heaters can become an inefficient waste of energy if not used properly.

In order to maximize your space heater, the first step is to size your space heater. This means getting the correct wattage that corresponds to the size of the room. Besides the room size, other room conditions such as room insulation and outdoor temperature also needs to be considered.

5 Steps To Size Your Space Heater

  1. Measure Your Room

Measure the length and breadth of your room (in ft) and multiply these two figures together to find out the area of the room in sq. ft.. For example, if the length of the room is 10 ft. and the breadth of the room is 8 ft., then the room area is 10 ft. x 8 ft. = 80 sq. ft.

  1. Calculate The Wattage

As a general rule of thumb, the ratio to consider is 10 watts to 1 sq. ft. of space. For example, a 10 ft. x 12 ft. room, for example, requires a 1200 watt space heater (120 sq. ft. x 10 = 1200 watts).

However, if you just stop here and get your space heater based on that, you will likely be disappointed when the heater does not perform to your expectations. This is because there are still a few factors to consider that might throw us off.

  1. Measure Your Ceiling Height

The ratio of 10 watts to 1 sq. ft. of space applies only to rooms with a standard ceiling height of 8 ft. However, if the ceiling height is greater than 8 ft. then you will need increased power and wattage to ensure the heater can heat up the increased size of the room.

Generally speaking, you should increase the wattage of your space heater an extra 25 percent for every 2 feet of extra space. For example, a 10 x 12 room with 10-foot ceilings would require a 1500 watt space heater.

Room area - 10 ft. x 12 ft/ = 120 sq. ft.

Wattage estimation - 120 sq. ft. x 10x 1.25 = 1500 watts

  1. Determine Your Room Insulation

If your room is poorly insulated or has a faulty window that lets in cold air, you will also need to factor in for greater wattage. Typically, an increase of 20% wattage would be a good place to start depending on how poor the insulation is.

Conversely, if your room is heavily insulated, then you can reduce the wattage by 20%. If you think that the insulation is moderate and decent, you can skip this step.

  1. Determine The Outside Temperature

The rate at which heat is lost from your room depends on the external environment as much as the construction scheme of the house. In particularly cold regions (below 32ºF), homes will experience way more heat loss than a house in a warm region. Therefore if you happen to be living in these extreme cold situations, you will need to increase the wattage ratio from 10 watts per square foot to 15 watts per square foot when you’re estimating space heater size.

Wrapping up

With this guide, you would have understood the main considerations behind sizing a space heater which should help you in your own purchase later on. The math may be slightly bothersome to calculate so do feel free to use our sizing calculator to your convenience!

Home Living Lab is a website on home comfort solutions. Visit for more information!

Article source:
This article has been viewed 260 times.

Rate article

Article comments

There are no posted comments.