As an Amazon Associate I earn from qualifying purchases. Links to Amazon on this page are affiliate links.
Why almost every plug-in heater stops at 1,500 watts
Updated
Look at the spec tables and you see the same line again and again: 1,500 watts, 12.5 amps. Six of the seven heaters on this site have it. An electric heater turns nearly all of its power into heat, so the same watts means the same heat: about 5,118 BTU per hour. No element, tube or fan design changes that number.
The math
The EIA gives 3,412 Btu for one kilowatthour of electricity. A 1,500 watt heater uses 1.5 kilowatthours in an hour, so it gives 1.5 x 3,412 = 5,118 BTU per hour. The Dr Infrared Heater DR-968 listing says it is "rated around 5200 BTU". That is the same figure, rounded up a little. The 200 watt Lasko MyHeat 101 lists 682 BTU, and 200 x 3.412 is 682. The listings agree with the math when they show BTU at all.
- DREO Atom One5,118 BTU/h
- Lasko 23 inch Ceramic Tower 7513205,118 BTU/h
- De'Longhi EW7707CM5,118 BTU/h
- Dr Infrared Heater DR-9685,118 BTU/h
- DREO HSH0065,118 BTU/h
- Amazon Basics Ceramic 1500W5,118 BTU/h
- Lasko MyHeat 101682 BTU/h
Why makers stop at 1,500
Watts divided by volts gives amps. 1,500 watts on a 120 volt outlet is 12.5 amps, and that is the amperage printed on these listings. As general guidance, many household circuits in the US are 15 amps, and a circuit often feeds several outlets and lights. A heater that drew much more than 12.5 amps would trip breakers in ordinary homes. So makers stop at 1,500 watts. This is a general explanation, not electrical advice. Your panel label tells you what your own circuits are rated for.
Same heat, different room claims
| Model | Watts | Listing claims | Watts per sq ft that works out to | Room the watts cover as top-up heat |
|---|---|---|---|---|
| DREO Atom One | 1,500 W | 200 sq ft | 7.5 | About 250 sq ft |
| Lasko 23 inch Ceramic Tower 751320 | 1,500 W | 150 sq ft | 10.0 | About 250 sq ft |
| Dr Infrared Heater DR-968 | 1,500 W | 576 sq ft | 2.6 | About 250 sq ft |
| DREO HSH006 | 1,500 W | 200 sq ft | 7.5 | About 250 sq ft |
| Lasko MyHeat 101 | 200 W | 50 sq ft | 4.0 | About 33 sq ft |
Lasko's own page for its 23 inch tower gives a maximum coverage area of 150 sq ft. The Dr Infrared spec table on Amazon says 576 sq ft, and the maker's page says its dual element gives up to 60 percent more heat output. Both heaters draw 1,500 watts. A blower and a quartz tube can change how the heat feels and where it goes. They cannot add BTU that the wall outlet did not supply.
For a yardstick, Cadet, which makes fixed electric heaters, says 1,500 watts suits a 250 sq ft room that already has central heat, and that the same room with no other heat needs 2,000 watts. By that rule 1,500 watts covers about 250 sq ft as top-up heat and about 187 sq ft as the only heat.
Room size the listing claimsRoom the watts cover at 6 W per sq ft (Cadet rule)
- DREO Atom One200 sq ft250 sq ft
- Lasko 23 inch Ceramic Tower 751320150 sq ft250 sq ft
- De'Longhi EW7707CMnone stated250 sq ft
- Dr Infrared Heater DR-968576 sq ft250 sq ft
- DREO HSH006200 sq ft250 sq ft
- Amazon Basics Ceramic 1500Wnone stated250 sq ft
- Lasko MyHeat 10150 sq ft33 sq ft
What to compare if not the heat
- Type: fan, radiator or infrared changes speed and noise. See heater types.
- Shutoff switches: tip-over and overheat. Four of the seven listings here name both.
- Thermostat: the DREO picks set by single degrees. Owners say the Lasko 23 inch Ceramic Tower 751320 moves in 5 degree steps.
- Low setting: only the Amazon Basics Ceramic 1500W listing states its low wattage, 900 watts.
- Noise: maker claims run from 34 dB to 43 dB on the fan heaters. The oil-filled De'Longhi EW7707CM has no fan.
Check your own room with the size and power use calculator, or compare all seven picks on the roundup page.
Safety note: keep any heater at least three feet from anything that can burn, plug it straight into a wall outlet, and turn it off when you leave the room or go to sleep. See the safety rules. This site is not electrical advice. If an outlet or plug gets warm, stop using it and ask a licensed electrician.