Although modern heaters have safety features built-in, you should never leave a space heater running overnight. Whether your heater runs on gas or electricity, it houses an element that gets hot enough to start a fire, and that's a good reason to avoid leaving it on at night. A typical electric heater draws 1,500 watts of electricity, and that much electricity heats the wires through which it flows. If you have older wiring that can't handle the heat, a fire could start behind the walls, and you may be none the wiser until it's too late. Even if you have good wiring, or you use gas heaters, you should turn off space heaters at night.
Space Heaters Cause Fires

According to The National Fire Protection Association, heating malfunctions are the second leading cause of home fires in the United States. When a heater failure starts a home fire, the culprit is a space heater 40% of the time. this translates into 25,000 residential fires a year involving a space heater. Half of all space heater fires start because something gets too close to the heater and ignites. In addition, older units without safety shutoff devices can start a fire if they tip over, and energy-hungry units can overheat old wiring improperly protected by out-of-date breakers or fuses. If a fire starts while you're asleep, you may wake to find your escape route blocked. …show more content…
Carbon monoxide is odorless and colorless, and by the time the levels are high enough to set off the alarm, you may have already inhaled a harmful dose - especially if you've slept through the early warning signs of carbon monoxide poisoning. The safest choice is to turn off your heater when you go to bed.
Space Heater