You probably know that security systems can detect fire, smoke, motion, and breaking glass, but did you know that you can also purchase a carbon monoxide detector? Carbon monoxide is produced by the incomplete combustion of fuel. Appliances such as water heaters, furnaces, stoves, and space heaters fueled by natural gas, propane, kerosene, or wood can emit carbon monoxide. When these appliances aren't installed, maintained, or used correctly, they can emit dangerous levels of carbon monoxide. A report from the U-S Environmental Protection Agency claims that up to thirty percent of newly remodeled energy efficient buildings have indoor air quality problems traceable to carbon monoxide gas. The problem lies in the strategy of builders to hold in as much heat as possible. This conserves energy, but can also limit free air exchange. To protect yourself from gas leaks, you can use a carbon monoxide detector. These units can run off your home's electricity or batteries. The A-C--powered units don't require battery replacement, but they won't work if the electricity goes out. You can, however, purchase premium units which use electricity with a backup battery unit. These standby batteries can last about four hours. Many of these units require periodic replacement of a sensor, which usually lasts about two years. You can find units that combine the replaceable sensor and battery in one unit. Some can provide you with a continuous digital readout of carbon monoxide levels from zero to 999 parts per million. Premium units will even store the highest level of carbon monoxide found in its memory bank. For more information on carbon monoxide detectors, contact a home security company in your area.