Seriously, this a terrible product. Sure, it may save your life on the ONE instance that it goes off when something is really wrong but you'll probably bash it to smitherines long before then after you hurt yourself trying to get out of a non burning, non gas filled home because the stupid thing is running one of its random "tests." You should buy this only if you hate your neighbors and/or love the adrenaline rush that comes with an alarm screaming at you.