Every year, about 3,000 people are killed in fires caused by portable heaters, according to a study by the National Fire Protection Association. Of those fires, most were caused by improper use.

As heating costs rise and temperatures dip into that bitter category, energy costs are on everybody's mind. Portable electric heaters can be an efficient way to warm your room or supplement central heating. For example, it might be nice to have a little extra heat from a portable heater by your couch when you're watching television. But you want to do so safely.

Here are some safety tips when using portable electric heaters, as recommended by the Association of Home Appliance Manufacturers, the U.S. Consumer Product Safety Commission, Underwriters Laboratories and the Electrical Safety Foundation International.

••Read the manufacturer's instructions and warning labels before using your portable electric heater.

••Do not leave an operating heater unattended.

••Always unplug heater when it's not in use.

••When you unplug the heater, don't yank at the cord. Pull the plug straight out from the outlet.

••Inspect the heater's cord periodically. Do not use a heater with a damaged cord.

••Do not use a heater with an extension cord or a power strip. Overheating of a power strip or extension cord could result in a fire.

••String out the heater's cord on top of area rugs or carpeting. Placing anything, including furniture, on top of the cord may damage it.

••Keep combustible materials, such as furniture, pillows, bedding, papers, clothes and curtains, at least three feet from the front of the heater and away from the sides and rear.

••Do not block heater's air intake or outlet.

••Keep flammable materials (such as paint, gas cans and matches) away from the heater.

••Do not use a space heater in damp or wet areas, unless it's designed for outdoor use or in bathrooms. Parts in the heater may be damaged by moisture.

••Check periodically for a secure plug/outlet fit. If the plug does not fit snugly into the outlet or if the plug becomes very hot, the outlet may need to be replaced. Check with a qualified electrician to replace the outlet.

••Do not plug any other electrical device into the same outlet as your portable heater. This could result in overheating.

••Heaters should be kept away from children. They should not be placed in a child's room without supervision.

••Place heater on a level, flat surface. Do not place your heater on top of a piece of furniture because it could fall off.