Updated November 2, 2026 · By Diego Gómez
Space heater safety: the 3-foot rule and other rules that matter
How to use a portable space heater safely: where to put it, what to plug it into, and the safety features to look for when you buy.
Portable heaters are safe when they're used properly. These are the rules the US Consumer Product Safety Commission and fire departments keep repeating.
- The 3-foot rule: keep the heater at least three feet from bedding, drapes, furniture and anything else that can burn.
- Hard, level floor: not on a rug, carpet or furniture.
- Not while you sleep: don't leave a space heater running when you go to sleep, and never place one close to a sleeping person.
- Plug it straight into the wall. Heater manuals generally warn against extension cords and power strips.
- Buy one with tip-over and overheat protection and a safety certification mark (UL, ETL or CSA).
- Keep working smoke and carbon monoxide alarms in your home.
All the heaters in our space heater and oil-filled radiator guides have tip-over and overheat protection.
Recommended
DREO 1500W ceramic space heater
- 1500 W (PTC ceramic)
- digital
- tip-over and overheat protection, child lock
One of the best-selling space heaters on Amazon: a quiet 1500 W ceramic heater with a real digital thermostat, tip-over protection and a child lock.
De'Longhi oil-filled radiator 1500W
- 1500 W, 3 settings
- digital panel, 24-hour timer
- oil-filled, silent
A silent oil-filled radiator that keeps heating after it switches off.
DREO 4 L humidifier
- 4 L
- up to 300 sq ft
- 28 dB
Quiet bedroom humidifier with a humidity setting and top fill, and one of the most reviewed on Amazon.
Affiliate links: if you buy, Amazon pays us a small commission at no extra cost to you. More info
FAQs
Can I leave a space heater on overnight?
The CPSC advises never leaving a space heater on when you go to sleep. If a bedroom is cold, warm it before bed or use a heated blanket or mattress pad with auto shut-off.
Is it safe to use a space heater with an extension cord?
Most manufacturers say no: a 1500 W heater draws a lot of current and can overheat a light-duty cord. Plug it directly into a wall outlet.