By: Michael Kabel

For the millions of American homes without central air conditioning and heating, space heaters offer a vital rescue from the freezing temperatures of winter. But space heaters cause thousands of fires throughout the country each year, and contribute to hundreds of deaths. More commonly, they present a burn hazard to people and pets alike if left unsupervised or poorly maintained.

Modern space heaters are safer, but the need for caution remains.

As home utility bills have risen steadily, public interest in space heaters has risen to new levels of popularity. Because space heaters warm only the space where they're used, families can target specific areas of the house to heat at specific times of day: the living areas in the daytime, the bedrooms in the evening.

The two most common forms of space heater run on either propane gas or electricity. Of the two, electric space heaters are more expensive to operate, while propane heaters can pose the risk of carbon monoxide poisoning. The less common open-flame heaters that are possibly still found in older buildings present the same hazards as any open fire and should be treated accordingly.

Many modern electric heaters use ceramic heating elements rather the old-fashioned nickel-chromium wires. This advance has allowed heater shells to be made from plastic, making them in turn more affordable to the average consumer. They are also much less likely to result in burns or fire. However, a fire hazard is still possible if the heater is plugged into old wall plugs or if its power plug becomes corroded. Don't stretch the cord out over the room, either, as this presents a tripping hazard.

Space heaters should be used sparingly and with proper vigilance.

The National Consumer Product Safety Commission recommends buying a heater that's the right size for the area you want to heat, following the specifications listed on the heater's packaging. Using a heater that’s too small or too large results in an inefficient use of electricity - which is counterproductive to saving money on utility bills. Heaters should also have automatic cutoff switches if the unit's temperature becomes to warm of if the unit falls forward.

Fire prevention experts recommend buying only heaters that have received independent certification from a qualified testing authority such as Underwriter's Laboratories. This certification means the heater has passed rigorous testing standards under various conditions.

Heaters should be turned off anytime someone leaves the room and before going to sleep at night. In addition, the area three feet in front of the heater should be kept clear of any furniture, clothing, or other items. Heaters should not be placed in laundry rooms, bathrooms, or anywhere towels or clothing might hang free. It’s also safest to keep the heater off the carpeting, if possible.

Space heater maintenance and storage

Never use an extension cord with a space heater. The powerful electrical current running from the wall to the heater may overload the cord's wiring, causing a short that may result in fire. Make sure the heater's power cord is kept clean and free of corrosion, rust, or other buildup at all times. The plugs should be kept dry and clean. Any repairs or replacements should be made by a qualified technician.

Keep the space heater free of dust by cleaning it with a dry rag while it is cool. In the warmer months, store the heater inside its original packaging, to help keep mold and dust from accumulating. These substances can present a burning hazard once the heater is used again.