Smoke detectors save lives. Many people may be lulled into a false sense of security thinking they have smoke detectors in their home. Smoke detectors that are not installed or maintained properly are not safe. Here are a few tips on what you need to know about buying, installing, and maintaining your smoke detectors: What should I buy? The National Burn Institute recommends only buying smoke alarms tested by Underwriters Laboratories (UL). You will also want to make sure the smoke detector has a battery backup. Smoke detectors that don't work in a power outage are no good. Consider buying a combination smoke detector and carbon monoxide detector, they may be more expensive, but well worth the money. There are two main types of smoke alarms, which are categorized by the type of smoke detection sensor used in the alarm. They are ionization and photoelectric. Ionization smoke detectors Ionization detectors respond quickly to flaming fires with smaller combustion particles. They contain a chamber with two plates that generate a small, continuous electric current. When smoke enters the ionization chamber, the smoke particles disrupt the current flow, which triggers the alarm. Photoelectric smoke detectors Photoelectric detectors respond more quickly to smoldering fires. They use a light beam and light receptor. When smoke is present between the light and receptor, the photocell sensor triggers the alarm. Combination smoke detectors The best smoke alarms can sense both types of fires (flaming and smoldering). For the highest degree of safety and preparedness, there are combination smoke alarms also that combine ionization and photoelectric detectors into one unit, called dual sensor smoke alarms. Check with your local fire department to see what kind of detector they recommend. Installation and Maintenance Smoke detectors should be installed on each floor, outside of every bedroom and sleeping area and near any air vents. Detectors should also be installed high on walls or on ceilings because smoke rises. Avoid installing detectors near windows, doors or where there are openings where smoke can escape. Check with your local fire department for specific regulations on the placement of detectors. Smoke detectors have a lifespan of about seven to 10 years, and it's important to replace old detectors according to the model's recommendations. Test your alarm’s batteries monthly and remember to replace all batteries at least once a year. Clean and vacuum the grill of your detector to get rid of dust and debris. Other maintenance includes a monthly testing of the alarm and cleaning with a vacuum hose about once every month.