How Much Electricity Does a Space Heater Use?

Christine Herrington

Christine is our Chief Editor and a contributing writer to the site.

Last Updated on January 20, 2022

There are several good reasons you may ask, “how much electricity does a space heater use?” If you can decrease your electricity use, you will slash energy bills and reduce your carbon footprint.

If you are considering getting a space heater, you might also be concerned about the additional expenses and environmental effects of consuming more electricity.

You can estimate how much electricity a space heater uses by looking at the wattage rating of your device, whether or not your device includes efficiency and cost-cutting features, insulation, and the size of the space you need to heat.

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Table of Contents

How to Measure Electricity

Before answering the question “how much electricity does a space heater use,” you need to know the basics of how to measure electricity.

Electricity is measured in watts (W) and kilowatts (kW), which is equivalent to 1,000W. A watthour (Wh) is the consistent generation or consumption of one watt over the duration of an hour. So if you use a 750W space heater for an hour, you have used 750Wh of electricity. If you leave it on for three hours, then you have used 2,250Wh.


Watt Ratings on Your Device

The watt ratings and settings options on space heaters show you how many watts each device uses per hour. The wattage rating is usually written on the device’s cord, in the owner’s manual, on the box, or the product description if you’re shopping online.

If a product tells you that it has a setting at 750W, that means that it uses 750 watts per hour. You will have to convert it to kilowatt-hours (kWh) to calculate costs, as the energy company charges you by the kilowatt-hour. You do this by dividing the watthours by a thousand. For example, a setting of 750Wh uses up .75 kWh

How Much Electricity Does a Space Heater Use?

Several factors affect how much electricity a space heater uses to efficiently heat your space, from the heat setting to your home’s insulation.

You can determine how much electricity your space uses by checking a utility bill. Another option is to check the specifics of your device.

You can multiply the space heater’s watt rating by the number of hours you want to leave it on per day. This is how much electricity your device will use each day.

Then, to check the cost, you must convert to kilowatt-hour and then multiply that number by the rate your electricity company charges you per kilowatt-hour.

For example, if you have a 1,500W heater, it uses 1.5kW per hour. If you leave your heater on for 2 hours per day, it uses 3kW of energy per day. If your energy company charges you 15¢ per kWh, it would cost you 45¢ per day to operate.


How Heat Settings and Insulation Affect Your Electricity Consumption

Many space heaters offer multiple settings. The most common ranges are warm, hot, and fan. The wattage settings usually range between 1,500Wh and 750Wh.  Whichever setting you use depends on a few factors such as insulation and the size of your space.

If you live in an old home, the quality of insulation influences how much wattage you should use for efficient heating.

Calculate the room’s square footage and then multiply that by the level of insulation of the room. A poorly insulated room can use up to 12.5W per square foot, while an average insulated room will use only 10W per square foot.

This means that if you want to heat 100 ft², and the insulation is bad, you should probably get a device that uses 1,250Wh of electricity. If your insulation is moderate, then you should get a space heater that uses up 1,000Wh.

Space Heaters: Energy Consumption and Cutting Costs

Getting the right type of space heater for your home or business is a big part of reducing your expenses. The caveat is that if you want to use a space heater to save money, you may need to lower the temperature in the rest of the house.

Otherwise, the cost of a space heater can add up over the months if added on top of the cost of central heating. A space heater should be used to heat one room or supplement central heating in one room at a time.


There are generally four types of space heaters:

1. Infrared heaters

These appliances heat people and things, like the sun. An infrared heater produces radiation and then blows it out into the room with a fan. This type is ideal for small rooms or spaces with high ceilings. They often come with an oscillating feature for even heat distribution.

2. Ceramic heaters

Ceramic models heat the air of an enclosed area. They usually have one or two coils wrapped around a ceramic center with a reflector that directs the heat to the room.

They often work quickly and can self-regulate for safety or cost-efficiency.

3. Convection heaters

Convection heaters intake air from the room and pass it across a heating element inside the housing and blow out the warm air to increase the room’s ambient temperature.

4. Micathermic panel heaters

Micathermic heaters are a hybrid between infrared and convection heaters, using approximately 20% infrared technology and 80% convection. These models do not feature a blower; rather, the panel features mica stone that produces electromagnetic heat when heated to a specific temperature.


Features to Look for to Reduce Energy Consumption

You can reduce your heating bills by opting for space heater modes that come with energy-efficient features, such as:

1. Timer

A timer allows you to preset the amount of time your heater operates, switching it off automatically when the timer goes off. This enables you to limit the amount of run time and decrease energy usage.

2. Adjustable Thermostat

The higher the temperature emitted by your heater, the greater the wattage needed to operate the appliance. By purchasing a heater with an adjustable thermostat, you can control the heat level and keep your room at a moderate temperature instead of overheating the space and wasting electricity.

3. Eco Mode

Many energy-efficient models feature an eco-mode that fluctuates between the highest selected setting and the lowest to maintain the space at room temperature.

Choose Energy Efficient Space Heater to Warm Your Home

To keep your home cozy during the colder months without sending your utility bill skyrocketing, it is crucial to determine the amount of electricity your space heater consumes. This measurement can help you manage your energy consumption, so heating your home is easier on your wallet and better for the environment.

When possible, choose Energy Star-rated appliances that are specifically designed for reduced energy consumption and produce lower emissions.

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