Why Bigger Space Heaters Don't Heat Better — Wired's Buying Guide Explained
Wired has published a detailed FAQ on space heaters, covering how they work, safety risks, and several recommended models.
Regardless of their physical size, most space heaters sold in the US and Canada put out roughly the same amount of heat, since 1,500 watts is the maximum safe load for a standard 15-amp household circuit. Electric heaters also convert nearly 100 percent of that electricity into heat, so a bulkier unit isn't inherently more powerful than a compact one — the "large room" versus "small room" marketing largely reflects branding rather than physics. What actually varies between models is how and how quickly heat gets distributed through a room.
Types of heaters
Most ceramic and PTC heaters use electrical resistance combined with a fan to push warm air out quickly, which heats a room's air fast but can use a lot of power for larger spaces. Oil-filled radiators warm more slowly but provide steady, quiet heat, while infrared (radiant) heaters warm people and objects directly rather than the surrounding air, making them well suited to large, open, or outdoor spaces. Heat pumps use far less energy since they move heat rather than generate it, but whole-home systems cost thousands of dollars to install, and affordable portable versions remain limited.
Safety
Although modern space heaters are heavily regulated, they still carry real risk. Per the US Fire Administration, space heaters caused more than a thousand fires annually in the US between 2017 and 2019 — just 3 percent of heating-related fires, but over 40 percent of the resulting deaths. Recommended precautions include never leaving a heater unattended (including while sleeping), plugging it directly into an outlet without extension cords, and keeping it at least three feet from flammable materials.
After testing dozens of units, Wired's additional recommendations include several Vornado models known for quiet, even heat; the compact Lasko Ellipse ceramic tabletop heater for fast personal warmth; and the Shark TurboBlade Cool + Heat, which combines a cooling fan with an accurate thermostat but runs fairly loud.
