All home inspections should include the inspection of all smoke and carbon monoxide detectors/alarms. Smoke alarms should be located in the following areas: In each sleeping room; outside each separate sleeping area; on each additional story of the dwelling, including crawl spaces and uninhabitable attics.
All smoke/carbon monoxide detectors and alarms have a test button that, when pushed, causes the alarm to sound. Also, most detectors have either a blinking or a solid light that glows to let you know that the alarm is getting power. Once a month, get up on a chair or use a broom handle for extra reach and push the test button. If you don’t hear anything, then your battery is dead. If after changing the battery, the smoke detector is still not working, immediately replace it with a new one.
While battery-operated units have a built-in device that chirps when batteries get low, signaling the need for replacement, common wisdom dictates not waiting until that point. Batteries should be replaced twice a year, once in the spring and once in the fall. My experience suggests that waiting for the alarm to tell you when to change the battery will result in chirping at 3 o’clock in the morning.
Most smoke alarms (smoke detectors) have a useful life of 7 to 10 years. After a period of ten years, a smoke detector has endured more than 87,000 hours of continuous operation, during which time the internal sensors have probably become contaminated with dust and the detecting elements start to wear out. Newer smoke detectors are more sensitive and more reliable. Homeowners should consider changing their smoke detectors every 7 to 10 years, batteries should be changed at least every year. (I change mine every fall when the time changes back to standard time.) Most newer homes have combination “hardwired” (with battery backup) smoke detectors. The smoke detectors are wired to a 120 Volt circuit as well as have a backup 9 Volt battery (for when power fails).
Carbon monoxide detectors/alarms should also be inspected for functionality and correct placement. Batteries should be replaced at least every year and the units changed after 5 years of use. Any dwelling that has a fuel (natural gas, propane, oil, coal, wood) fired heater or appliance, a fireplace, or an attached garage is required to have carbon monoxide detectors. If any of these conditions occur, the home must have an operational carbon monoxide alarm installed within fifteen feet of the entrance to each room lawfully used for sleeping purposes. Do not install carbon monoxide detectors directly above or beside fuel-burning appliances, as appliances may emit a small amount of carbon monoxide upon start-up.
Combination smoke and carbon monoxide detectors are also available. They should be installed in all areas required for either a smoke or smoke alarm/detector. Newer alarms have the ability to communicate with each other so when one detects smoke or carbon monoxide all alarms in a home will sound. If you are replacing alarms in your home be sure that they all have this ability.