If you use a portable electric space heater to provide supplemental heat for your home, before you plug it in, you may want to consider how much it will cost to operate this heater. This does not have to be a mystery, because you can calculate how much your electric heater will cost to operate with some simple information.
Units of Energy
Electricity is measured and sold by the kilowatt-hour. This is a measurement of power which not only takes into account the amount of energy, but the time frame over which it is consumed, similar to the measurement of horsepower in motors. A kilowatt-hour is equivalent to 1,000 watts of electricity, used over a period of one hour.
Calculating Heater Energy Use
Most electric appliances have the wattage of electricity that they use stamped on the appliance, or on an information plate attached to the appliance. Electric heaters may have two or three different settings, and the information plate or owner's manual may give the wattage of the heater at each setting. To calculate the power use in kilowatt-hours, multiply the wattage that the heater uses by the number of hours per day that it will operate, and divide that amount by 1,000. A 1,500 watt electric heater operated for eight hours per day will use 12 kilowatt-hours of electricity per day.
Cost of Use
Multiply the number of kilowatt-hours that your heater uses per day by the price you pay for each kilowatt-hour of electricity. This price varies depending on your location. At 0 per kilowatt-hour, a 1,500 watt heater used for 8 hours per day will cost 90p per day, or £28.0 per month. Some utilities offer a lower rate for electric power during certain times of the day, typically at night, so your price may be lower when the heater is used then.
Portable household meters are available to measure how much electricity most plug-in appliances use. The Kill-a-watt meter is one device that plugs directly into the wall, and you plug the appliance into the device. The meter measures the amount of watts that the appliance has consumed since it was plugged in, and the total time that the usage has been measured, to calculate kilowatt-hours. This will help measure the electrical use of appliances where the wattage is unknown.