How Much do Smart Smoke Detectors Cost?Always weigh the costs against the benefits you might get from a smart smoke alarm. On average, you can expect most smart smoke detectors to cost around $100, though some units cost as much as $250, which can be up to 10 times more expensive than normal units. This can make replacing all of the existing smoke detectors in your home very expensive. To keep costs down, consider using traditional units throughout your home with smart smoke detectors in main areas. Traditional smoke detectors typically cost between $10 and $40. Here are a few basic models that are popular on Amazon:First Alert BRK 3120B $27. 18 This hardwired alarm uses both photoelectric and ionization sensors to detect smoke. It does not have a carbon monoxide sensor. First Alert SCO7CN $25. 97 This battery operated model has a photoelectric smoke sensor as well as a carbon monoxide detector. In addition to its siren, the unit can voice warnings and instructions.