A CO detector makes several different sounds and they mean very different things. Here's how to tell a low battery from an actual alarm — and what to do in each case.
A carbon monoxide detector is the only way to know about a gas you cannot see, smell, or taste. Which means when yours starts making noise, the single most important thing is knowing which noise it's making.
They sound different for different reasons, and the difference matters enormously. Here's how to read it.
A pattern of four quick beeps, a pause, then four more beeps means the detector is sensing carbon monoxide right now.
Get everyone outside immediately — people and pets — and contact your local fire department from outside. Do not open windows first, do not try to find the source, and do not go back in to investigate. Opening windows can also make it harder for responders to identify where the CO came from.
Leave the detector where it is and let the fire department confirm the levels and locate the source before anyone re-enters. Common sources are a malfunctioning furnace or water heater, a blocked flue, a running car in an attached garage, or a generator or grill used too close to the house.
Symptoms of CO exposure look like flu without a fever: headache, dizziness, nausea, confusion, weakness. If anyone has these — even without an alarm — get outside and seek medical attention.
A single short chirp at a regular interval is the low-battery warning. This is the one that always seems to start at 3am, because a drop in overnight temperature reduces battery voltage just enough to trigger it.
Replace the battery. If the chirping continues after a fresh battery, move on to the next section — the unit may have reached end of life.
Please don't pull the battery and leave it out. It's a tempting 3am decision and it leaves your family without protection until you remember to deal with it.
This is the one most homeowners don't know about. CO detectors have a sensor that degrades over time, and the unit is designed to tell you when it's no longer trustworthy.
Five chirps in a row, repeating roughly every minute, means the detector has expired. A new battery will not fix it — the sensor itself is spent. The unit needs to be replaced.
Most CO detectors are rated for five to seven years from the date of manufacture, not the date you installed them. Take the unit off the wall and look at the back — there's a manufacture date printed on it. If you moved into your home more than five years ago and haven't replaced the CO detectors, there's a real chance at least one is already past its useful life.
A pattern of three chirps generally indicates a unit malfunction. Try replacing the battery and pressing the test button. If it persists, replace the detector — a CO alarm reporting a fault is not one you want to rely on.
California requires a CO alarm on every level of the home and near each sleeping area. Carbon monoxide mixes fairly evenly with air, so mounting height is less critical than for smoke alarms, but avoid placing them directly above or beside a fuel-burning appliance, within fifteen feet of cooking or heating appliances, or in very humid areas like bathrooms, where false alarms are common.
Many San Diego homes, particularly those built before the requirements tightened, have gaps in coverage. If your home has an attached garage, a gas furnace, a gas water heater, a gas range, or a fireplace, you want detectors and you want them current.
Walk the house. For each CO detector: press and hold the test button to confirm it sounds, then take it off the mount and read the manufacture date on the back. Anything past five to seven years gets replaced regardless of whether it passes the test — the test button checks the horn and circuitry, not the sensor.
A quality combination smoke and CO detector runs $25 to $40. It is, by a wide margin, the cheapest safety equipment in your home.
Detector ages are exactly the kind of thing that's impossible to keep in your head and easy for someone else to track. For Livd members, we log the manufacture date of every detector in your home during visits, flag the ones approaching end of life, and replace them when the time comes — so you're never relying on a unit that expired two years ago.
Already a Livd member? Add "CO detector check" to your task list in the Livd app and we'll audit every unit on your next scheduled visit.
Not a Livd member yet? Schedule your free home walkthrough at livdhomes.com — detector audit is part of every walkthrough, and it's a good place to start.
