How much does it cost to run a personal space heater?

At 800 watts used 6 hours a day, a personal space heater costs about $0.82 per day, $8.16 per month and $97.92 per year on an average rate of 17¢ per kWh — roughly 576 kWh and 230.4 kg of CO₂ over a year. Enter your own electricity rate and usage in the calculator above for a figure matched to your bill.

Personal space heaters work by passing electricity through a heating element—typically nichrome wire or ceramic—that glows hot and radiates warmth into the surrounding area. Unlike central heating systems that distribute warmth through ducts, a space heater concentrates its output in one zone, which is why it can feel intensely warm while drawing power almost continuously. Most units run between 750 and 1500 watts; even at the lower end of that range, a space heater consumes far more power per minute than a typical light bulb or small appliance. The actual power draw depends on whether the heater is set to high or low mode—many models have switchable wattage settings—and how frequently the thermostat cycles the heating element on and off.

One critical factor affecting total running cost is thermostat behavior. Many personal space heaters include built-in thermostats that sense room temperature and turn the heating element off once the target is reached, then back on when temperature drops. In practice, this cycling behavior means the unit rarely runs at full rated wattage for extended periods. However, if you place a heater in a poorly insulated room, near cold windows, or in a space with drafts, the thermostat will cycle more frequently, keeping the element on longer and increasing overall consumption. Conversely, using a space heater in a well-sealed room, closing doors to prevent heat loss, and setting the target temperature conservatively all reduce how often the element needs to fire up.

When choosing a space heater, look beyond wattage alone. Convection heaters—which warm air and circulate it—heat a room gradually but often more efficiently than radiant models that emit direct infrared heat. Ceramic heaters tend to be safer and more durable than older coil-based designs and heat up faster. Oscillating models distribute warmth more evenly throughout a space, reducing hot spots and dead zones. The presence of a real thermostat (not just a timer or dial) is essential; cheap models without temperature sensing will run at full power continuously and waste energy significantly. Also consider whether the heater has automatic shut-off features for tip-over safety or overheating—these are not just safety features but also prevent accidental continuous operation.

A common misconception is that space heaters are always a cheaper way to heat a home than central systems. While a space heater used strategically in one room for a few hours can cost less than heating an entire house, running multiple heaters around a home or using one continuously in a large, drafty room can actually be more expensive and inefficient. Space heaters work best as supplementary heat sources: heating the room you're occupying while lowering your central thermostat, or warming a finished basement or addition without conditioning empty areas of the home. Pre-owned or discount space heaters may seem attractive, but older designs and units lacking thermostats or safety features often waste energy and pose fire hazards. Investing in a modern unit with solid build quality, a reliable thermostat, and safety certifications typically saves money and provides safer operation over time.

Placement and maintenance also influence real-world efficiency. Position the heater away from walls, furniture, and curtains to allow air circulation and prevent obstruction of the thermostat sensor. Keep the intake vents clear of dust and pet hair, which can restrict airflow and make the unit work harder. If you use your heater seasonally, clean or replace filters before storage. Finally, resist the temptation to supplement with a second space heater in the same room—two units running simultaneously will spike power consumption far more than you might expect, with diminishing returns on actual warmth delivery.