Plug-in heater buying guide
By Dan Chase, Home-heating tester · 11 years reviewing portable heaters · Updated August 2026
Almost every plug-in heater on the market converts electricity into heat at the same efficiency. What separates a good one from a frustrating one is how quickly you feel it, whether the whole room catches up, and whether you trust it enough to leave it on.
Start with wattage matched to the room: roughly ten watts per square foot for a normally insulated space with eight-foot ceilings. Then decide the form factor. A direct plug-in unit disappears into the wall socket and warms fast, which suits bathrooms, bedrooms and offices. A floor tower holds a larger room more steadily but demands space and a cable route.
Check for two cutoffs before anything else: overheat shutoff on every unit, and tip-over shutoff on anything that stands on the floor. Then plug it into a wall outlet directly — extension leads and power strips are not rated for a sustained 1,500W draw, and that is where heater accidents start.
Finally, think about the parts nobody lists on the box: how loud it is at 11pm, whether the controls are usable in the dark, and where it lives in July.
Our scoring criteria
Time to warm25%
How many seconds until the air leaving the vent actually feels hot on your hands.
Even coverage20%
Whether the far corner of the room catches up, or stays the spot nobody sits in.
Running cost20%
What one warm room costs per evening compared with turning the central heat up.
Safety behaviour20%
Overheat shutoff, tip-over response and how hot the outer shell gets to the touch.
Living with it15%
Noise at night, cable clutter, controls you can use half-asleep, and where it stores.
Our test protocol
- 1We ran each unit in the same 150 sq ft room at a 12°C start temperature and logged vent-air temperature at 10 seconds, 1 minute and 10 minutes.
- 2Coverage was measured with thermometers at three points, including the far corner, after 20 minutes of running.
- 3Noise was recorded at one metre on the highest setting, then again on the lowest, with the room otherwise silent.
- 4Safety behaviour was checked by blocking airflow and, for floor units, tilting them past 45° to confirm the cutoffs actually fire.