What Is the Most Energy-Efficient Space Heater?

• They all turn 100% of their electricity into heat. The DOE says electric resistance heating "is 100% energy efficient in the sense that all the incoming electric energy is converted to heat." That is true of ceramic, oil-filled, infrared and fan heaters alike.^[1]
• So watts decide the cost, not the type. Any 1,500-watt heater on high uses 1.5 kWh an hour: about $0.27 at the U.S. average of 18.19 cents per kWh, or about $65 a month at 8 hours a day.^[3]
• Type changes how the heat feels. The DOE says a radiant (infrared) heater warms the people and things in front of it, so it can make sense if you sit near it for a few hours.^[2]

• 228 of 378 plug-in heaters claim to save energy or lower your bill.^[7]
• Most of those claims are about running less, through a thermostat, an ECO mode or a timer. That can be true: the DOE says a thermostat avoids "the energy waste of overheating a room."^[2]
• 18 listings make a claim that doesn't hold up as written (16 different claims, since some sellers repeat theirs). They give an electric heater an efficiency figure below 100%, say it saves energy compared with other heaters, or call a low setting or a low-wattage heater more efficient. Low settings and small heaters use less power because they make less heat.
• 26 listings put a number on the savings, and 14 of them say "up to 40%" from ECO mode. Only 3 say what the savings are compared with.
• False savings claims are not allowed. The FTC says it is unfair or deceptive to falsely represent the energy savings a product will give.^[5]

The 16 claims that don't hold up, word for word

1. Buy the right size. The DOE says not to buy an oversized heater. Heater maker Dimplex plans on 10 watts per square foot, so a 1,500-watt heater suits a room of about 150 square feet. Most plug-in heaters are 1,500 watts on high, so a bigger box does not mean more heat.^[2][4]
2. Use a thermostat. A heater that switches off once the room is warm uses less than one that runs nonstop.^[2]
3. Heat only the room you are in, and turn the furnace down for the rest of the house. The DOE says that is when a space heater can cost less. See what a heater costs to run in your state.^[2]
4. For a room you heat all winter, look at a heat pump. The DOE says heat pumps cut electricity use by about half compared with electric heaters. A DIY mini split heats one room this way.^[1]
5. Warming just yourself? A heated blanket uses a small fraction of a heater's power.

These are the same picks as on our space heater cost page. Each listing states a thermostat, tip-over and overheat shutoff and a UL, ETL or CSA safety listing. Both are 1,500 watts, so like any 1,500-watt heater they cost about $0.27 an hour on high.^[7]

Quick heat for a small room

Chikit ceramic fan heater

1,500 W, ETL listed, thermostat, tip-over and overheat shutoff.

$24.34 at Amazon, checked October 17, 2026

Check price on Amazon

Quiet, steady heat for a bedroom

Amazon Basics oil-filled radiator

1,500 W, ETL listed, thermostat, tip-over and overheat shutoff.

$70.19 at Amazon, checked October 17, 2026

Check price on Amazon

Note: the Amazon Basics oil-filled radiator listing is on the list above for its energy-saving line. We pick it for its safety features and price; the claim does not change how much heat it makes.

Is an infrared heater more efficient?

It turns electricity into heat no better than any other electric heater. The DOE says radiant (infrared) heaters can be the better choice when you sit near one for a few hours, because they warm you and what is around you instead of the whole room. That saves energy only if it lets you run the heater less. ^[2][1]

Does ECO mode save energy?

It can, by running the heater less, usually on a lower setting or by switching off once the room is warm. It does not make more heat from each kWh. 14 of the listings we read promise "up to 40%" savings from ECO mode, and most don't say compared with what. ^[7]

Are oil-filled heaters cheaper to run?

Not per hour on the same setting. A 1,500-watt oil-filled heater and a 1,500-watt ceramic heater both cost about $0.27 an hour on high at the U.S. average electricity price. The oil-filled one stays warm after it cycles off, which feels steadier, but it does not save energy. ^[3][1]

What is the cheapest space heater to run?

The one you run least. Every 1,500-watt heater costs the same per hour on high. Pick one with a thermostat so it switches off once the room is warm, and turn the furnace down for the rooms you are not using. See what one costs where you live on our space heater cost page. ^[2][3]

Are energy-saving claims on heaters allowed?

Sellers must be able to back up savings claims. The FTC says it is unfair or deceptive to falsely represent the energy savings a product will give. In 2012 the ad watchdog run by the Better Business Bureaus told the seller of EdenPURE heaters to stop claims that it saves more on heating bills. ^[5][6]

1. 1

   U.S. DOE Energy Saver: Electric Resistance Heating (archived copy, January 1, 2026)

   Read October 17, 2026. "Electric resistance heating is 100% energy efficient in the sense that all the incoming electric energy is converted to heat." "Because of electricity generation and transmission losses, electric heat is often more expensive than heat produced in homes or businesses that use combustion appliances." "If electricity is the only choice, heat pumps are preferable in most climates, as they easily cut electricity use by 50% when compared with electric resistance heating." "Room heaters can consist of electric baseboard heaters, electric wall heaters, electric radiant heat, or electric space heaters."

2. 2

   U.S. DOE Energy Saver: Small Space Heaters (archived copy, March 24, 2026)

   Read October 17, 2026. "In some cases, small space heaters can be less expensive to use if you only want to heat one room or supplement inadequate heating in one room." "Radiant heaters emit infrared radiation that directly heats objects and people within their line of sight, and are a more efficient choice when you will be in a room for only a few hours and can stay within the line of sight of the heater." "They can also be more efficient when you will be using a room for a short period because they save energy by directly heating the occupant of the room and the occupant's immediate surroundings rather than the whole room." "Choose a thermostatically controlled heater, because they avoid the energy waste of overheating a room." "Select a heater of the proper size for the room you wish to heat. Do not purchase oversized heaters." "Make sure the heater carries the Underwriter's Laboratory (UL) label." "Electric small space heaters can be more expensive to operate than combustion space heaters." "For convection (non-radiant) space heaters, the best types incorporate a heat transfer liquid, such as oil, that is heated by the electric element. The heat transfer fluid provides some heat storage, allowing the heater to cycle less and to provide a more constant heat source." "Space heater capacities generally range between 10,000 Btu and 40,000 Btu per hour, and commonly run on electricity, propane, natural gas, and kerosene"

3. 3

   U.S. EIA: average residential price of electricity (same figure as our space heater cost page)

   Year-to-Date through July 2026: 18.19 cents per kWh, U.S. average.

4. 4

   Dimplex (heater maker): Electric heater technical support, "How big a heater do I need to heat my room?"

   “The general rule for electric heat is to use 10 watts of heat per square foot of space i.e. 1000 watt heater will heat 100 square feet (10' x 10') in a standard insulated room.” At 10 W per sq ft, 1,500 W covers about 150 sq ft.

5. 5

   FTC: Synopsis of Federal Trade Commission Decisions Concerning Energy Saving Claims (Notice of Penalty Offenses; transcript created April 7, 2022)

   Read October 17, 2026. "It is an unfair or deceptive act or practice to represent falsely the fuel or energy savings expected to result from home improvement materials and products." "It is an unfair or deceptive act or practice to represent directly or by implication expected energy savings or reductions in fuel bill prices when consumers will not ordinarily realize such savings or reductions."

6. 6

   ERSP (BBB-administered ad self-regulation), August 2012: ERSP Recommends Suarez Discontinue Certain Claims for 'EdenPURE'; Finds Advertiser Can Support 'Made in America' Claim

   Read October 17, 2026. "“…the new EdenPURE heats better, faster, saves more on heating bills, and runs almost silent.”" "“…made in the U.S.A. using Patent Pending exclusive duel heating technology. Our heaters are more efficient, more effective, and better built.”" "ERSP determined that the advertiser could not support claims related to monthly savings, and recommended the company discontinue the claims in future advertising. ERSP recommended Suarez discontinue comparative safety claims and comparative superiority claims."

7. 7

   Amazon.com space heater listings: the title and feature bullets of 378 plug-in electric heaters

   Read October 13 and October 17, 2026. We read the listing text only, not images, A+ content or footnotes. Heater prices on this page checked October 17, 2026.

Related: space heater cost to run · space heater room-size claims · DIY mini splits · smart thermostats