Most Efficient Space Heaters

Are you looking for the most efficient space heaters available?

Do you want to stay warm without spending a lot of money this winter?

If so, this guide is for you.

Below, you’ll find a list of the most energy-efficient space heaters you can buy today, as well as a wealth of other information to help you make your decision.

Choosing the most efficient electric space heater can seem like a challenge. With so many different types and designs of economical heaters available on the market, it’s hard to know what to look for.

In this article, you’ll find out what the best energy-efficient electric heaters are, complete with specific recommendations for each type of device.

To help you make an informed choice, we’ve included an in-depth guide to everything that affects the efficiency of a heater.

By the time you’ve finished reading, you’ll have all the tools and knowledge you need to find the best energy-efficient space heater for your needs and save money on heating this winter.

Disclosure: Home Air Guides is reader-supported. As an Amazon associate and affiliate for independent brands, we earn from qualifying purchases made through the links on our site. Learn more.

Most Energy Efficient Space Heaters Reviewed in This Guide

Here’s a quick comparison chart showing the top efficient space heaters. We’ll cover each aspect of these units in the reviews section below, but this gives you an idea of what’s available and an easy way to compare them.

ImageHeater DetailsPrice
 Laskwo AW300 Space HeaterLasko AW300 Space Heater
  • Tower heater with bladeless design
  • Type: Ceramic
  • Thermostat: Digital
  • Coverage: 300 sq. ft.
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Vornado MVH Space HeaterVornado MVH Space Heater
  • Compact and portable heater
  • Type: Electric Fan
  • Thermostat: Dial
  • Coverage: 300 sq. ft.
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Dr. Infrared DR-968 Space HeaterDr. Infrared DR-968 Space Heater
  • Most efficient space heater for large rooms
  • Type: Infrared
  • Thermostat: Digital
  • Coverage: 1,000 sq. ft.
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Heath Storm HS-1500-PHX Space HeaterHeat Storm Phoenix HS-1500-PHX Space Heater
  • Can be wall mounted or stand on the floor
  • Type: Infrared
  • Thermostat: Digital
  • Coverage: 750 sq. ft.
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De'Longhi TRD40615E Space HeaterDe’Longhi TRD40615E Space Heater
  • Good option for kids and pets
  • Type: Oil Filled
  • Thermostat: Digital
  • Coverage: 150-300 sq. ft.
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Pelonis NY1507-14A Space HeaterPelonis NY1507-14A Space Heater
  • Best value for an energy-efficient space heater
  • Type: Oil Filled
  • Thermostat: Digital
  • Coverage: 150-300 sq. ft.
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De'Longhi HCX9115E Space HeaterDe’Longhi HCX9115E Space Heater
  • Dual fan system for faster heat
  • Type: Panel
  • Thermostat: Digital
  • Coverage: 150-300 sq. ft.
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De'Longhi HMP1500 Space HeaterDe’Longhi HMP1500 Space Heater
  • Budget-friendly option; wall-mountable or floor standing
  • Type: Panel
  • Thermostat: Digital
  • Coverage: 150-300 sq. ft.
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Most Energy Efficient Space Heater Reviews

The Lasko AW300 Space Heater in Gray

1. Lasko AW300 Ceramic Space Heater

If you’re looking for an energy-efficient space heater featuring a modern, bladeless design, the Lasko AW300 will be a great choice.

Capable of heating up to 300 square feet, this ceramic tower unit comes with a convenient remote control to switch between the high and low heat settings. The digital control also features an automatic thermostat and an 8-hour timer.

Thanks to the built-in overheat protection, bladeless design, and cool-touch surface, the Lasko AW300 is a safe, family-friendly economical electrical heater. It’s also outfitted with a rear filter for protection from dust and debris.

On the aesthetic front, it’s definitely among one of the best looking efficient space heaters. The slim, sleek design features neatly contrasting black and silver, perfect for complementing any modern interior.

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The Vornado MVH Space Heater in Black

2. Vornado MVH Fan Heater

One of the greatest advantages of the Vornado MVH is its portable, compact design. With small dimensions and a weight of under 4 lbs, it’s a highly practical choice if you plan on storing it out of sight or taking it with you from room to room.

The heater features three fan speed settings, ranging from 750W to 1500W, enabling you to be in control of energy consumption. The thermostat dial has 7 temperature control settings, and will automatically turn the unit on and off to maintain the set temperature and conserve power.

Despite its small size, the Vornado MVH is capable of heating rooms of up to 300 square feet, using vortex air circulation.

This energy-efficient heater is also exceedingly safe to use. It has a cool-touch case and the fan is shielded with a finger-safe cover. Thanks to automatic safety shut-off mechanisms, the unit will turn itself off if it tips over or if the airflow becomes blocked.

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The Dr. Infrared DR-928 Space Heater in Wood

3. Dr. Infrared DR-968 Infrared Space Heater

This unit is the top choice among the most energy-efficient space heaters for warming up large rooms and apartments.

By combining infrared technology with fan-powered convection heat, the DR-968 can heat spaces up to 1000 square feet. The addition of the fan makes it approximately 60% more effective than other infrared heater models, and it also enables the unit to use 100% of the heat that it produces.

Those features alone make this the most economical electric heater available.

The sturdy box design with a wooden case gives this heater a stylish, retro look, and the attached wheels make it easy to take it with you from room to room. Thanks to the digital thermostat and temperature display, you can be fully in control of adjusting the heat output.

Although there’s no guarantee the case will always stay cool to the touch, the heater does feature an automatic safety switch-off function in case it overheats or tips over.

Interestingly, it’s possible to attach a humidifier to this space heater, enabling you to heat up the room and counteract dry, winter air all at the same time, without additional energy input. So if you’re looking for the best energy-efficient space heater that can keep the air moist, then be sure to select that upgrade during checkout.

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The Heat Storm Phoenix HS-1500-PHX Space Heater in White

4. Heat Storm Phoenix HS-1500-PHX Infrared Space Heater

The main feature that sets this heater apart from the other economial electric heaters on this list is the fact that it can be mounted on the wall, just like a radiator.

It comes with a wall-mounting bracket and feet, so you can choose between hanging it on the wall or having it stand on the floor.

In both positions, this infrared, energy-efficient electric heater can warm up even large rooms, up to 750 square feet. The digital thermostat with a LED display makes it easy to adjust and maintain the temperature, and thanks to the remote control, you can do so from the comfort of your sofa or bed.

As an added bonus, this infrared heater measures the humidity and oxygen levels in the room so they don’t get too low, thanks to the proprietary HMS Technology.

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The De'Longhi TRD40615E Space Heater in Gray

5. De’Longhi TRD40615E Oil Radiator Space Heater

If you’re worried about the safety of your kids or pets around the space heater, this oil radiator is an efficient, safe choice.

Oil radiator space heaters usually feature fins — like traditional, old-fashioned radiators — for effective heat distribution through a large surface area. These work really well, but do pose a risk for kids and pets — the surface can get hot, and it’s easy for a child’s fingers to get stuck between the fins.

This efficient electric heater from De’Longhi, however, uses a unique solution in the form of patented thermal slots. Thanks to this technology, the sides of the heater don’t get as hot, as well as being finger-safe. Furthermore, this solution provides an additional 25% of the radiant surface for quickly heating up space.

It also looks a bit more modern and sleek than many other oil radiators. It comes in light grey or black, so you can choose a color that best suits your interior.

When used on its own, this space heater can warm up approximately 150 square feet of space. The coverage is extended to 300 square feet if there’s another heat source in the room.

The heater features a digital thermostat with a display, three heat settings, and a timer. The energy-efficient ECO mode can be enabled to maintain the temperature in the room using a minimum amount of power, saving you money on the electric bill.

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The Pelonix NY1507-14A Space Heater in Black

6. Pelonis NY1507-14A Oil Radiator Heater

This is an excellent choice of space heater for those on a tight budget. Offering great value for money, this oil radiator from Pelonis can heat up 150 square feet of space without using a lot of power.

The efficient electric features a programmable thermostat, with an LCD screen, a 10-hour timer, three heating options, and five temperature settings. These are all easily adjusted using a remote control.

Although oil radiators are usually quite bulky, this one’s lightweight, sleek, and portable. Resting on four wheels, the heater is easy to move from room to room. Built-in safety features include protection from overheating and an automatic switch-off function when the heater tips over.

This electric oil radiator is mostly black, with two color options for the display casing (silver or gold).

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The De'Longhi HCX9115E Space Heater in Gray

7. De’Longhi HCX9115E Panel Heater

The dual fan system in this electric space heater from De’Longhi is its main advantage, enabling the unit to heat up the room much faster than single-fan-forced air heaters.

The heater features an LCD display and a digital adjustable thermostat with multiple heat settings. For the best energy-saving results, you can use the ECO mode, which automatically maintains the optimal temperature in the room with the lowest energy consumption.

Safety features include overheating protection and automatic switch-off in case the heater tips over or otherwise become unstable.

Helpfully, this heater also has an anti-freeze function, which helps to prevent the pipes from freezing by turning on when it detects particularly low temperatures in the room.

Lightweight, slim, and very modern in style, this heater can act as a freestanding unit or be mounted on the wall. Both a wall-mounting bracket and a set of feet are included with the heater. Despite its small size, this heater can handle up to 300 square feet of space.

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The De'Longhi HMP1500 Space Heater in Black

8. De’Longhi HMP1500 Panel Heater

Characterized by a very slim design, this energy-efficient heater is an excellent budget-friendly option if you don’t have a lot of space.

The sleek panel features two dials for setting the heating power and temperature. Thanks to being able to choose between 750W and 1500W output, you’ll never be using more electricity than you really need for optimum heat.

This heater can be wall-mounted (using the attached bracket) to save on space — and it’s slim enough to fit into any room.

It’s also highly portable as a freestanding unit, thanks to the fact that it’s outfitted with a convenient handle for carrying as well as a set of wheels.

The HMP1500 is capable of heating a room of up to 300 square feet in size. Like most of the other best energy-efficient heaters reviewed on this page, it comes with overheat and tip-over protection features.

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Energy Efficient Space Heater Buying Guide

How Do Space Heaters Work?

Space heaters offer a quick and efficient solution for warming up a room, either as a primary heat source or as an additional heating method.

Unlike central heating, space heaters don’t require any existing infrastructure to work — there’s no need for pipes or extraction. The vast majority of space heaters are electric, which means all you need to do is plug them in.

This also makes space heaters very portable — you can take them with you from room to room if needed.

There are several types of space heaters available on the market, and each works in a slightly different way depending on the technology it uses. However, with the exception of infrared heaters, they all share one common principle: turning electricity into heat that warms up the air.

Science Direct defines electric heating like this, “Electric Heating is a process in which electrical energy is converted to heat.” When you turn an electric space heater on, you allow an electric current to reach the unit’s components. As this current passes through an electric resistor, it’s transformed into heat, warming up heating coils inside the heater.

What happens next will depend on the type of heater. Some units feature just the coils, in which case they simply radiate heat, gradually warming up the surrounding cold air. Certain types of heaters use ceramic plates or oil to store the heat generated by electricity and stay hot for longer.

Other designs feature a fan, which helps with air circulation. The fan draws in cold air from behind the heater, pushing it through the hot coils and blowing warm air as a result — much like a hairdryer would.

Depending on the technology used, some space heaters will be more efficient at heating up a room with less power consumption than others. Let’s find out which types make for the most energy-efficient space heaters.

What are the Most Efficient Space Heaters?

It’s virtually impossible to point to a single best space heater, as a lot depends on the circumstances in which it will be used — such as the size and layout of the room.

We’ll go into detail about the most economical electric heaters available to help you determine the most efficient space heater type for your needs.

Electric units make for the most efficient, safe space heaters, so we will focus on:

  1. Ceramic Space Heaters
  2. Infrared Space Heaters
  3. Oil-Filled Space Heaters
  4. Panel Space Heaters

Ceramic Space Heaters

Inside this type of heater, there are ceramic plates that absorb the heat generated by the heating coils. You can think of the plates as storing the heat created by the electric current within the unit.

Although they warm up very quickly, the ceramic plates will continue to radiate heat even after the heater has been turned off. In practice, this means the ceramic type units make for some of the most efficient space heaters out there — they stay warm for a while with no power consumption. (You can learn more about how ceramic heaters work here.)

Ceramic space heaters are best suited for small areas and can take a long time to warm up large areas in the home. To speed up the heating process, some ceramic heaters are outfitted with a fan, which forces more cool air into contact with the hot plates.

If you’re looking for the best space heater for bathroom, a ceramic fan heater is a good choice due to its efficiency, price, and various types available.

Infrared Space Heaters

Although infrared space heaters are also electric, they’re the only type on this list to use a different heating method.

Rather than heating a coil and warming the air, these relatively large space heaters emit electromagnetic waves that warm physical objects. Specifically, they convert electricity into infrared light, using a series of coils. A reflector then directs the light outwards.

Objects (such as furniture) and people absorb this light, warming up in the process. So, rather than heating up the air inside the room, infrared units directly heat up your body and the objects around you.

For this reason, the infrared type will make for the most efficient electric heater in medium-sized, furnished rooms. They don’t work as well in large, empty spaces in which there is nothing to absorb the heat from infrared light.

The infrared type of energy-efficient space heaters has the advantage of working instantly — you’ll immediately feel warmer in front of the unit. (You can learn more about how infrared heaters work here.)

Some top rated infrared heaters are also outfitted with a fan, which is used to circulate the warmth generated by the coils. This way, none of the heat is lost and you get maximum efficiency for the energy input.

Lastly, in case ‘infrared radiation’ sounds a bit ominous, don’t worry — infrared units make for perfectly safe space heaters for you, your kids, and your pets.

In fact, they’re the safest kind of electric space heater, since they don’t get nearly as hot as the coils inside other electric heaters — so they pose virtually no fire or burn risk.

You’ll often find this type of heating technology in electric fireplaces that stand on the floor and wall mounted electric fireplaces. It’s also available on the best patio heaters that are designed to be heat lamps.

Oil-Filled Space Heaters

In oil-filled space heaters, the electric heating element warms up a specialist kind of oil inside the unit. The oil then circulates around the inside of the radiator—like a unit, heating the metal housing. The entire housing begins to radiate heat, warming up the air around it.

There’s a good reason why oil space heaters look like old-fashioned radiators. The purpose of the many thin fins (or ribs as they’re sometimes called) is to create the biggest surface area for maximum heating efficiency. Put simply, this design means that there are more hot surfaces to warm up the air.

The oil inside this kind of space heater has two important properties: a high specific heat capacity and a high boiling point. Thanks to these, it can conduct heat extremely efficiently without the risk of boiling.

One of the ways in which the best oil filled radiator heaters are particularly energy-efficient heaters is that the housing stays hot for a while after the heater has been turned off. These radiators may take a relatively long time to warm up, but they don’t need to be on constantly to provide heat.

Because oil-filled space heaters don’t feature fans or any other method of air oscillation like other types of electric heaters, they’re best suited for small spaces where you can sit close to the unit. They make for energy-efficient, cheap space heaters for close-up use in an office or a small living room. The lack of fans also makes them some of the quietest space heaters available.

If you want to learn more about the difference between oil heaters and other electric heaters, you can visit our oil heater vs electric heater page.

Panel Space Heaters

Panel space heaters take their name from the flat, usually rectangular shape of their housing. They feature a series of coils that heat up as an electric current passes through a resistor — just like we described earlier on.

Once these coils have become hot, they radiate warmth which is absorbed by the surrounding air.

In a process called convection, a panel heater warms up the air above it, which then rises up. As it does so, it replaces the colder air above. The resulting air current eventually encircles the room.

The most efficient space heaters in the panel category feature a fan, which helps to warm up the room quicker without using much more electricity. The exact coverage of a panel heater will vary from model to model, but most units can warm up a room of up to 300 square feet. You can view our best wall mounted electric heaters to see the top units that are available.

Unlike most of the other types of space heaters, panel heaters can be mounted on the wall. This makes them the ideal choice for rooms without much space, like a bedroom, and for areas where additional heating is needed regularly. In fact, we recommend panel heaters as the safest space heater for a bedroom with children because they can be installed up and out of the way.

How to Calculate the Efficiency Of Space Heaters

When looking for the most economical electric heater, it’s important to be able to calculate exactly how much it would cost you to run each unit. This way, you’ll be able to make informed comparisons between different options and choose the best one for you.

There are several factors that go into calculating the efficiency of space heaters. In order to calculate the average daily cost of running a heater, you need the following information to know for sure how much electricity does a space heater use:

  • The power use of the heater: The vast majority of space heaters use 1500 watts at a maximum, although many give you the option to choose a lower power use setting. Check the manual or the specifications online to make sure.
  • Your current kWh rate: You can find this on your electricity bill. In the U.S., the average is approximately $0.13/kWh.
  • The number of hours you plan to use the heater per day: When determining how much you’ll be using the heater, take into account the size of the room and the purpose of the heater. If you only need it as an additional heat source during colder evenings, you’ll be using it a lot less than someone who intends to run it as the only heating in the room. Remember to also take into consideration other relevant factors, such as the height of the ceiling and the quality of wall insulation.

Armed with this information, you can use this convenient calculator to determine how much it will cost you to run the heater per hour, day, month, and year.

Formula for calculating the cost

If you’d rather do the calculations yourself, here’s a simple formula:

Watts x hours per day x kWh rate ÷ 1000 = average daily cost

So, we take the power use of the heater in watts and multiply it by the number of hours it will be used per day. Then, multiply this number by the kWh rate, and finally, divide the result by 1000.

For example, let’s assume your space heater runs at 1500 watts, you plan on using it for 4 hours per day, and your kWh rate is $0.13. The equation would look like this:

1500 x 4 x 0.13 ÷ 1000 = $0.78 average daily cost

With this formula, you can accurately predict the level of efficiency of various units and find the best space heater for your needs.

Features to Look for in an Energy Efficient Space Heater

Most Energy Efficient Space Heaters

Although different kinds of energy-efficient space heaters come with various attributes, there are several features common to all units.

It’s a good idea to keep these in mind when comparing economical electric heaters and weighing their pros and cons. The importance of each feature will depend on your individual needs and expectations.


Naturally, every electric space heater is going to use electricity when turned on. Wattage is a way to determine just how much electricity is required to run a heater. Watts are units of power, which can be used to measure the rate at which energy is transferred.

The higher the wattage of an appliance, the more energy it uses per second and the faster it works. Electric space heaters turn energy into heat, so in very simple terms, higher wattage means quicker heating.

The majority of electric space heaters have a wattage of 1500, though some give you the option of adjusting power use — offering low-power settings such as 750W. Using a 750W heater will provide less heat, but also cost less.

On utility bills, energy use is represented in kWh — kilowatts per hour. 1 kilowatt equals 1000 watts, so a 1500W heater will use 1.5 kilowatts. If your electricity rate is, for instance, $0.10 per kWh, running a 1500W heater for an hour will cost $0.15 (1500W = 1.5kW; 1.5kW x 0.10 = 0.15).

Thermostat Options

The term thermostat in the context of space heaters refers to the inbuilt controls for setting the temperature or heat level.

Thermostats on space heaters can be either analog or digital. The first refers to a dial that you have to turn in order to change the temperature setting. Usually, the dial is used to choose between two to three heat levels offered by the heater, or to set a temperature. Some heaters feature a slider instead of a dial.

Digital thermostats, meanwhile, usually feature an LCD screen and a series of buttons for adjusting the temperature, mode, and power usage more accurately. Some models of space heaters with digital thermostats also include a remote control.

The type of thermostat doesn’t directly impact how energy efficient a heater will be. However, some digital thermostats are equipped with specific energy-saving features.

The U.S. Department of Energy recommends that you always “choose a thermostatically controlled heater because they avoid the energy waste of overheating a room.”

ECO mode

The best and most efficient space heaters will feature an ECO mode in addition to the standard options. While in this setting, the heater will use only enough power to maintain a set temperature, rather than constantly heating the space.

For instance, if you set your heater to 20°C (or 68°F), it will work on maximum heat until the air in the room reaches this temperature. It will then switch off, turning back on when the temperature drops.

So if you were wondering, “will space heaters save money?”, then the answer is yes when using an ECO mode. The ECO mode is the most economical choice you’ll find in space heaters today.

Safety Features

In general, electric space heaters should be used under supervision at all times. Realistically, however, it may not be possible to constantly monitor a heater for several hours a day.

For this reason, modern space heaters are outfitted with a series of safety features to ensure that they don’t pose a risk to you, your family, and your apartment. These are particularly important if you have kids or pets, but they’re good to have in any circumstances.

Overheat protection

This is the most basic safety feature that virtually all electric space heaters have. In the event that the heating element inside the heater reaches a dangerously high temperature — either due to malfunction or improper use — the device will switch itself off automatically.

Overheating is only likely to happen if the heater is left running for longer than the recommended maximum. Each heater will come with an instruction manual, which includes the upper limit of time the heater can be run continuously.


Many heaters feature a timer that either works automatically or can be set to a certain amount of hours. A built-in 8-hour timer, for instance, will automatically turn the heater off after 8 hours of operation.

This is a safety measure similar to the timers in hair straighteners or clothes irons. If you accidentally fall asleep while the heater is on or forget to turn it off before leaving the house, it will switch off by itself.

Tip over protection

Although most space heaters are quite sturdy, they can still be accidentally tipped over. Many heaters feature a sensor that can determine whether the device has been knocked over, and automatically turn it off.

This feature is especially useful to have if you have pets capable of knocking over the heater.

Cool-touch surface

Up until a few years ago, the exterior of most space heaters would get extremely hot during prolonged use. This posed a danger of injury when touching the heater, as well as a fire risk in case something flammable came into contact with the hot surface.

Nowadays, the best space heaters have a cool-touch case. Manufacturers even find ways to add cool-touch cases to oil-filled space heaters.

Thanks to this solution, the heater’s exterior surface may warm-up, but will stay safe to touch. This is particularly important if the heater will be used around small children, as it will minimize the risk of burns and give you additional peace of mind.


Many space heaters that are energy efficient are also easy to move around the room or the apartment.

If you need your heater to be portable, pay attention to its weight and design elements that make it easier to carry or move the device. Lighter heaters are often outfitted with a handle, while heavier ones usually have a set of caster wheels.

This can also be important when looking for the best space heater for large rooms as there are often cold spots. And if you can move the unit around, then you can find the perfect position to eliminate those colder areas in a big room.


If you plan on using an efficient electric space heater in one room only, it might be a good idea to pick a model that you can mount on the wall.

Panel heaters are the most likely type to be wall-mountable, given that they’re the right shape, size, and weight to be safely attached to a wall. Suitable models often come with brackets that you can use to secure the heater to the wall with sufficient airflow and spacing.

Conveniently, there are space heaters on the market (usually panel ones) that come with both a wall-mounting bracket and a set of wheels, so you can use them as a permanent fixture or a portable heater, as needed.

And although they’re not mentioned here, you can also opt for a plug in baseboard heater that sits up against the floor of a wall. You can see our reviews of the best baseboard heaters here if this interests you.

Space Heater Safety Tips

All of the units reviewed above make for safe space heaters for home use. However, as with any other electric device, a space heater has to be used in accordance with manufacturer guidelines in order to be safe.

With this in mind, here are the essential safety tips to keep in mind when using electric space heaters:

  • Read the manual that comes with your space heater and follow the instructions at all times. Remember to only use the heater for the purposes specified in the manual, in the recommended way. For instance, don’t attempt to wall-mount a space heater that’s meant to be used as a freestanding device.
  • Take care when choosing where to position the heater in the room. Keep in mind that it should be placed well away from any flammable objects or materials, and pick a spot in the room where the heater will be least likely to get knocked over.
  • For prolonged use, make sure to plug the heater directly into the socket and avoid using an extension cord. Extension cords are only safe for light, temporary use — when used for several hours a day with a high-wattage heater, they can easily overload and cause a fire.
  • If possible, don’t leave a working space heater unattended for longer than necessary. Even with a built-in timer, it’s safer to only use space heaters when you’re in the room.
  • Unless you know exactly what you’re doing, don’t try to fix a broken space heater by yourself. Done improperly, home repairs on electric devices can constitute a serious danger to you, your family, and your home. It’s always best to leave any repairs to the experts

Other Factors That Affect Room Heat

The efficiency of a space heater depends on more than the characteristics of the device itself.

There are other factors that affect how well the heater will work, mostly to do with the size and features of the room or apartment you’re looking to heat.

Room size

While reading our most efficient space heaters reviews, you’ve probably noticed that each heater is capable of heating a certain amount of square feet.

Predictably, the larger the room, the more time and energy it will take for a space heater to adequately warm up the area. It’s therefore important to have an idea of the size of the room(s) that need heating before choosing a heater.

The easiest way to find out the size of the room is to measure it yourself. For rectangular rooms, all you need to do is multiply the length of the room by its width. For instance, if your room measures 15 by 20 feet, it has an area of 300 square feet (15 x 20 = 300).

For L-shaped rooms, split the area into two rectangular sections, calculate the area of each, and add them together to get the total area.

Rooms with corners, meanwhile, should be split into a rectangle and a triangle. To find out the area of the triangular section, measure the length and height of the triangle — so, the two sides that meet at a right angle. Then, use the following formula: (0.5 x length) x height = area.


If the room has archways or cased openings rather than doors that you can close, it will be more difficult to warm up.

Most space heaters work best in closed areas with little airflow. If there’s no new (and cold) air coming in, it’s easier to warm up the air already in the room and maintain a given temperature.

In the absence of doors, an infrared space heater may be the best choice. This type of heater doesn’t warm up the air, so limiting airflow into the room is not as important.

Ceiling height

If the room has a high ceiling, it will take longer to warm up with a space heater. The reason for this is that hot air is lighter than cold air, so it has a tendency to move upwards. If the ceiling is high, there’s more air in the room and more space above your head for the warm air to fill.

The ceiling height is the distance from the floor to the surface of the ceiling. The standard ceiling height in the U.S. is between 8-9 feet. Anything above 9 feet is considered a high ceiling.

Wall insulation

When the walls are well insulated, it means they keep warmth inside the house and prevent the cold from outside from seeping inside. A good level of insulation will improve the efficiency of a space heater — once it has warmed up the room, the warmth won’t be displaced by the chill of the walls.

For this reason, using a space heater in areas with poor insulation will be less effective. Even the most energy-efficient space heater will need more time and energy to warm up a poorly insulated garage than a well-insulated apartment.


Drafts in apartments and houses are usually caused by improper insulation around the windows and doors. These cracks and gaps let in cold air, requiring your space heater to work much harder to keep the space warm.

If possible, try to fill in or cover any gaps causing a draft. If your heater has a fan, it’s important to position it away from the window or door, facing the middle of the room.

Common Questions About Energy Efficient Space Heaters

Most Efficient Electric Space Heaters

Which type of heater is cheapest to run?

An infrared space heater will usually generate the lowest running costs. However, this type of heater is also usually more expensive than others.

The actual per-hour cost of running each type of heater is likely to be very similar across all types since most units have the same wattage (1500W).

What determines the efficiency of a heater is how quickly and effectively it warms up the room during this space of time. As we’ve seen in the previous sections of this article, this depends on a number of factors, such as the size of the room and ceiling height.

You can learn more about the differences between infrared heaters and the top competitors in our posts on ceramic vs infrared heater and electric heater vs infrared.

Is it cheaper to run the heat or a space heater?

It depends on the circumstances — in particular, the number of rooms you’re looking to heat.

If you need to warm up one or two rooms, it will be cheaper to use a space heater. For heating an entire house, meanwhile, the central heating will be a more efficient solution.

As pointed out in this research study at Cornell University, you can get the most energy efficiency with a space heater by warming up the entire house to 60 degrees and then using the space heater to increase the heat in one room up to 70 degrees. By using a space heater and central heating system today, you can reduce your total heating bill each month.

Do space heaters raise electric bills?

The short answer is yes — electric space heaters use electricity to run, and this will reflect on your utility bill.

The exact amount to expect depends on your kWh price, heater wattage, and the frequency of use. Running a typical (1500W) space heater for six hours a day would cost $30 – $40 per month, on average.

There are space heaters on the market which don’t require electricity to run and therefore won’t raise your electric bill. Instead, they use another kind of fuel — most often propane or kerosene.

Do all 1500 watt heaters heat the same?

Technically, yes — every 1500W heater will produce the same amount of heat. Specifically, 3.4 BTUs per watt. A BTU (British thermal unit) is a universally used unit of heat.

However, space heaters can differ in the way they distribute this heat. Devices that feature fans, for example, usually warm up the air in the room more quickly, while heaters with ceramic plates stay warm for longer after they’ve been turned off.

Can you leave a space heater on overnight?

The short answer is no — space heaters should not be left running unattended.

Even with all the safety features in modern space heaters, such as tip over and overheating protection, it’s not safe to have them on while you’re asleep.

The primary reason for this is that they can cause a fire. The unit itself may not overheat, but it can heat a flammable object in the room to the point of combustion. In apartments with out-of-date wiring, an unattended heater can also cause an electric fire.

It’s therefore much safer to run the heater for a few hours immediately before you go to bed. This should keep the room warm enough for a comfortable night’s sleep, without creating a fire hazard.

Enjoy Your New Energy Efficient Space Heater

We hope you’ve found our guide to the most energy-efficient space heaters both informative and helpful.

The key takeaway is that the features of the heater itself are just as important as the environment in which it will be used, and there are lots of factors that go into just how efficient the device will be.

Now that you know exactly what to look for, choosing from the most efficient space heaters available should be easier than ever.

Armed with this information, you’re just one step away from enjoying a new, best energy-efficient electric heater with full confidence that it’s the best, most economical choice for your needs.

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About Patrick Holmes

Patrick is a Senior Air Quality & Comfort Specialist. He conducts in-depth research and analysis for our product reviews and buying guides in order to offer expert recommendations for people who are seeking to improve their indoor air quality and comfort. (See Full Bio)