CO Alarms: Where and How to Place Them
Last verified: September 2026
Good placement keeps carbon monoxide away; alarms are the backstop that warns you if it ever drifts toward the house. Here's how to choose, place, and maintain them the right way. Rather talk it through? My number is (330) 200-8042.
Carbon Monoxide Alarms, Placed and Maintained Right
Carbon monoxide alarms are the backstop that warns you when CO drifts toward the house — even after perfect placement. The essentials: choose battery or battery-backup alarms so they work when the power is out, put one on every level and outside every sleeping area, follow the maker's placement sheet, test monthly, and replace each whole unit by the date printed on it. There's a printable page-by-page version up top.
Common Questions
1 Why can't I use a plug-in CO alarm?
A plug-in-only alarm goes dark during the very outage you're running the generator through. Choose a battery-powered or battery-backup alarm so it keeps watching the air when the power is out. A plug-in alarm that also has a battery backup is fine.
2 How many alarms do I need, and where?
At least one on every level of the home — including the basement — and one outside every sleeping area, close enough to wake a sleeper. A larger or spread-out home may need more so no area is left unwatched.
3 Do smoke alarms detect carbon monoxide?
No — smoke and carbon monoxide are different dangers sensed in different ways. You need CO coverage as well, either as separate CO alarms or as combination smoke-and-CO units.
4 How do I place each alarm exactly?
Follow the instruction sheet that comes with your specific alarm. Different models are designed for different heights and positions, so the maker's sheet — not a rule of thumb — is what to follow.
5 How often do I test and replace them?
Test each alarm about once a month and change batteries when it chirps for them. The whole alarm also wears out: replace it by the date printed on the unit, since a test beep checks the horn, not the sensor.
6 What if someone in the house is hard of hearing?
Makers offer alarms with a louder or lower-pitch sound, a bright strobe light, or a bed-shaker that vibrates the mattress. Check what each maker offers and test it with the person it's meant to wake.
Would You Rather I Just Help?
Picking the right alarms, placing them where they'll be heard, checking the dates on any you already have, and making sure everyone knows the plan is exactly the kind of visit I'm glad to make. $99 flat, 30-day come-back-free.
Would you rather I just do this for you?
No shame in it — plenty of folks would rather hand it off, and that's what I'm here for. I'll come to your home, set it up right, and make sure it's working before I leave. Flat $99 per visit — no jargon, no upsell, and every visit is 30-day come-back-free.
Not a hardware job? I can often fix it remotely for $49 — a secure screen-share, up to 2 hours, that you watch the whole time and can end whenever (included free for $39/mo Support Plan members, and it counts toward the $99 if it turns out I need to come out).