subject: Choosing and Using Electric Heaters [print this page] Electric heaters can be an excellent and safe way to keep warm, and they can even help you save energy by allowing you to warm up the room you are in and turn down the heat in the rest of the house. Following a few tips will help you choose the most effective model for your intended use and also use it safely.
To begin with, all portable 120 volt electric heaters are limited by the Electrical Code to a maximum wattage of 1500. Almost all models available will offer from 1200 to 1500 watts of heating capacity, and the difference between 1200 and 1500 watts is not especially significant in terms of heating ability. All portable electric heaters heat through the principle of electric resistance, meaning that they create heat by using a heating element which gets warm when power flows through it. This means they are all 100 percent efficient; all models of the same wattage will produce the same total amount of heat and deliver the same 100 percent efficiency, producing 3,413 btu/hour of heat for every 1000 watts they consume.
HOW BIG AN AREA WILL THEY HEAT?
This depends on different factors, such as the insulation level of the room, the height of the ceiling, and whether the heater is the sole form of heat or just a supplemental heat source.
As a rough rule, with standard electric heating (anything but a heat pump) you need ten watts of heating power for every square foot of floor area.The maximum wattage you can get in a portable, 115 volt electric heater is 1500 (due to safety and code requirements), so this means that a portable electric heater can be the sole heat source for an area up to 150 square feet. As a supplemental heat source the area can be much larger. If you want to use electric heating for a large area, you either have to use many portable heaters, each on a separate circuit, or install a 240 volt circuit and use a higher wattage model. For instance, on a 20 amp 240 volt circuit, up to 3840 watts of electric heating can be used.
