Energy Adviser: Space heaters warm rooms efficiently, affordably



Using a portable electric space heater to warm up a cold room or take the chill out of a drafty garage workshop may be a good solution for short-term needs. But if you buy and use a space heater this winter make sure you understand power usage trade-offs and the safety issues.

Small space heaters are typically used when a main heating system is inadequate or too expensive to operate. Or they may be a good way to boost the temperature of a single room such as a bedroom or small family room.

Space heaters come in a variety of sizes and wattages. When buying a small portable electric space heater, follow these guidelines from the U.S. Department of Energy and Clark Public Utilities.

• Select a heater of the proper size for the room you wish to heat. Most come with a general sizing table.

• Only purchase newer models that have up-to-date safety features. Make sure the heater has the Underwriter’s Laboratory, or UL, label attached.

• Choose a heater with temperature controls, since it will prevent you from wasting energy by overheating a room. Some have programmable timers that will turn the heater on and off.

• Don’t be misled by advertising touting energy-efficiency. An electric heater will produce about 3,400 BTUs of heat for each kilowatt-hour of electricity consumed.

The wattage of a heater determines how much heat it will produce. A 1,500-watt heater (the most common wattage) will produce an equal amount of heat regardless of its price or advertised special features or new technology. All electric space heaters are 100 percent efficient because there is no heat lost in ducts or up a flue. In other words, a $40 heater is as energy-efficient as a $400 heater.

It is true people can save on central heating costs by using a portable space heater, but only if they turn their central system to a much lower temperature or even shut it off. For most of us that’s just not practical. For every degree you lower your heat thermostat, you can save from 1 percent to 2 percent on the heating portion of your utility bill. However, depending on how many space heaters are operating and for how long, any savings could be offset by additional power use.

Safety comes first

Safety must be a top priority when using space heaters. The U.S. Consumer Product Safety Commission estimates that more than 25,000 home fires every year are associated with the use of space heaters, causing more than 300 deaths and sending an estimated 6,000 people to hospital emergency rooms.

Electric space heaters are the only unvented space heaters safe to operate inside your home. Do not use unvented kerosene or propane heaters inside, since their gas emissions can kill you.

Here are space heater do’s and don’ts from the U.S. Consumer Product Safety Commission:


• Place the heater on a level, hard, nonflammable surface, such as a ceramic tile floor.

• Keep the heater at least three feet away from bedding, drapes, furniture, and other flammable materials.

• Keep children and pets away from space heaters.

• Turn the heater off if you leave the area.

• Plug portable electric heaters directly into the wall outlet. If an extension cord is necessary, use a heavy-duty cord of at least 14-gauge wire.

• Buy a unit with a tip-over safety switch that automatically shuts off the heater if the unit falls over.


• Never leave a space heater on when you go to sleep.

• Don’t place a space heater close to any sleeping person.

• Don’t use portable propane space heaters indoors or in any confined space unless they are specifically designed for indoor use.

Also, be sure to place smoke alarms on every level of your home, outside of sleeping areas and inside each bedroom. Guard against carbon monoxide poisoning by installing carbon monoxide alarms in your home. Make sure that your batteries in all alarms are fresh and working.

Energy Adviser is written by Clark Public Utilities. Send questions to or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.