How to Choose a Space Heater

A space heater is the cheapest way to stay warm in one room without cranking the whole house’s furnace — but the wrong one can trip breakers, run up your bill, or become a genuine fire hazard. The right pick comes down to matching the heater type to the room and buying one with the safety features that actually matter.

Match the heater type to the room

Every portable electric heater converts electricity to heat at almost 100% efficiency, so the differences aren’t about how much heat you get per watt — they’re about how that heat is delivered, how fast, how quietly, and how safely. A ceramic fan heater warms a small room in a minute or two; an oil-filled radiator takes twenty but holds the warmth long after it shuts off. Pick by the job, not the wattage on the box.

Tip: for a garage, unheated shop, or jobsite, look at dedicated supplemental and utility heaters rather than a living-room ceramic unit — they’re built for cold, dusty, high-square-footage spaces and often offer 240V models.

Size it to the room: watts and square footage

The rule of thumb is 10 watts per square foot for a room with average insulation and 8-foot ceilings. A standard 1,500-watt heater comfortably takes the chill off about 150 square feet — a bedroom, home office, or small living room. Bigger, drafty, or poorly insulated spaces need more, which usually means a 240V unit rather than a standard outlet.

One hard electrical limit worth memorizing: a standard 120V household circuit tops out around 1,500 watts of continuous draw, which is exactly why nearly every plug-in heater maxes out there. Run two 1,500W heaters on the same circuit and you’ll trip the breaker. Never run a space heater on an extension cord or a power strip — plug it straight into a wall outlet.

Safety features that actually matter

Space heaters cause thousands of home fires every year, and nearly all of them trace back to a missing feature or a cheap unit. A few dollars more buys real protection. Look for these before anything else:

• Tip-over shutoff — cuts power instantly if the unit falls over. Non-negotiable if you have kids or pets.
• Overheat protection — a sensor that shuts the heater down before internal parts get dangerously hot.
• Cool-touch housing — the exterior stays safe to touch; essential around children.
• A safety certification mark — look for UL, ETL, or CSA listing on the label. Skip anything without one.
• Auto-off timer — shuts down after a set period so it never runs all night unattended.
• Sturdy base — a wide, weighted stand resists tipping in the first place.

Brands like Lasko, Honeywell, DeLonghi, Dr. Infrared, and Vornado build these protections in as standard. Whatever you buy, keep it at least three feet from bedding, curtains, furniture, and anything else that burns, and plug it directly into the wall. Pair a bedroom heater with working smoke detectors and, since any combustion or electrical appliance warrants it, check your home safety and detector supplies while you’re at it.

Thermostats, controls, and running costs

A heater with a real adjustable thermostat — not just high/low — cycles on and off to hold a set temperature instead of blasting full power the whole time. That’s the single biggest factor in your electric bill. A programmable or digital model with a timer and eco mode pays for itself over a winter.

The math is simple: a 1,500W heater draws 1.5 kilowatt-hours per hour at full tilt. At the U.S. average of roughly 16 cents per kWh, that’s about 24 cents an hour, or under $2 for an eight-hour evening — far cheaper than heating the whole house to warm one room. A good thermostat cuts that further because the heater isn’t actually running full-power the entire time. If you’re heating a fixed spot regularly, an in-line or wall thermostat control gives you even finer command over cycling.

Don’t overlook the whole-comfort picture

Sometimes a space heater is the wrong tool. If a room is cold because heated air isn’t reaching it, clear or replace the heating registers and vents before you buy anything that plugs in — a $12 register fix can beat a $60 heater. Winter dryness makes a room feel colder than it is, so a humidifier can let you stay comfortable at a lower temperature. And for milder chills, a cozy electric blanket heats you directly for a fraction of a heater’s draw.

Pick by how you’ll use it

Frequently asked questions

Still weighing ceramic against an oil-filled radiator for your space? The staff at your local independent hardware store can point you to a safe, right-sized unit in person — or ask us here and we’ll help you match a heater to your room.