How to Size a Small Electric Space Heater A rule of thumb for sizing a space heater is 10 watts for each square foot.
Using this rule, a 1500 watt space heater would heat a 12'x12' room. (144 sq. ft.)
Factors that reduce the effectiveness of any small space heater are drafts, inadequate insulation, large window space, an open floor plan, or a room with a stairway.
Situations such as these may require an additional space heater, but here's where you have to be careful. Since the circuits on most older homes are wired for only 15 amps, and a 1500 watt heater draws 12.5 amps, no other electrical devices should be plugged into the same circuit.
In order to avoid a potentially hazardous situation determine which outlets are on each circuit by plugging a small lamp into the outlet and flipping the circuit breakers off one at a time until the lamp turns off or purchase a circuit breaker finder.
Only purchase newer model heaters that have all of the current safety features like overheat protection and a tip-over switch.
Locate the space heater on a level surface away from foot traffic.
Keep it at least 3 feet away from combustible items such as drapes and furniture. This is the number one cause of space heater fires.
According to Georgetown, MA., Fire Chief Al Beardsley, "What takes place is the material (drapes, mattresses) dries out and over time the chemical composition of the material changes and combustion occurs."
Don't use the space heater as a dryer for clothing, wet towels, etc.
If you have little ones running around put the space heater into one of those scissor-like kiddie corrals so the kids can't get at it or buy a space heater capable of wall mounting.
A number of micathermic heaters can be mounted on the wall but one model in particular, the DeLonghi HHP1500 Safeheat Mica-Panel Heater, has been known to pose safety hazards. You can read more about it here.
Although some space heaters are sold as "waterproof" I don't recommend their use in bathrooms. However, if you need to warm up the bathroom you can still plug the space heater in a few minutes before you plan on bathing and then remove it.
Plug the space heater directly into the wall outlet. Do not use extension cords or power strips. Most retail extension cords and power strips are intended for use with low powered electronics such as computers and TVs, not devices that draw high amps such as coffee machines, microwave ovens and electric space heaters.
The Consumer Products Safety Commission reports that each year about 28,000 house fires are attributed to space heaters, resulting in 300 related deaths.
This doesn't mean space heaters are inherently dangerous, only that caution and common sense should be exercised in the pursuit of additional comfort for you and your family.