CO & Smoke Detectors: The Only Warning You Get

Where should CO and smoke alarms go?

Placement follows how CO and smoke actually move through a house.

• CO alarms: outside each sleeping area (hallways), on every level, and near — not inside — an attached garage door.
• Smoke alarms: inside every bedroom, outside each sleeping area, and on every level including any finished attic.
• Don't mount CO alarms right next to gas appliances (a few feet of separation prevents nuisance alerts during normal startup) or in dead-air corners.

How long do CO and smoke alarms last?

An often-overlooked detector failure isn't a dead battery — it's an expired unit still hanging on the ceiling. CPSC has advised replacing CO alarms every five years and smoke alarms that are more than 10 years old, and says the recommended replacement age is in the product literature or available from the manufacturer. CPSC also notes the test button checks the circuitry, not the accuracy of the sensor — so an out-of-date alarm can pass the button test. Replace the unit, not just the battery.

Where does CO come from in a SoCal home?

CO is incomplete combustion. In our housing stock the usual suspects are an aging furnace with a compromised heat exchanger, a water heater with a blocked or backdrafting flue, a range used as a heater (never do this), and vehicles idling in attached garages. The appliances are our trade: a combustion check during furnace and water-heater maintenance verifies each one is burning clean and venting fully outdoors.

What's our work, and what's an electrician's?

Honesty about scope: Power Pro services the gas appliances that produce CO — furnaces, water heaters, and their venting — and we check combustion and flue draft on maintenance visits. Replacing plug-in or battery detectors is a homeowner task; hardwired, interconnected detector circuits are an electrician's work. What matters is that the detectors exist, are in date, and get tested.