Drafty windows and unevenly heated rooms mean that many people turn to space heaters to stay warm in winter. But those portable heaters come with a caution: They cause 25,000 fires yearly, send 6,000 people to the emergency room with burns and result in 300 deaths.
When purchasing a portable electric space heater, make sure it bears an Underwriter’s Laboratory label. Look at the sizing table, and buy the appropriate size for the room or area you plan to heat. Make sure the heater is thermostatically controlled. Always place the heater on a flat surface away from high-traffic areas; plug it directly into a wall outlet, if possible. If you must use an extension cord, choose the shortest one you can, made of heavy-duty cord. Finally, buy a space heater with a tip-over safety switch. That way, if someone accidentally topples it, the heater shuts off.
Source: energy.gov