CO & Smoke Detectors: The Only Warning You Get

Where the alarms belong

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.

The detector itself has a lifespan

The most common detector failure isn't a dead battery — it's an expired sensor still hanging on the ceiling. CO sensors degrade chemically over 5–7 years; smoke sensors last about 10. Every unit has a manufacture or replace-by date on the back. If yours predates that window, the button test can still chirp reassuringly while the sensor is effectively blind. Replace the unit, not just the battery.

Where CO actually comes 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.