Smoke and carbon monoxide alarms in rentals: placement, testing and replacement
Where smoke and CO alarms go in a rental, how often to test them and when to replace them, from NFPA and CPSC guidance, plus the chirping alarm call.
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Smoke and carbon monoxide alarms are the cheapest safety equipment in a rental and the easiest to forget. They show up as a chirping-battery text at 11:00 PM ET, a tenant who pulled one off the ceiling while cooking, or an alarm that is fifteen years old and nobody knows it.
This post sums up the national guidance on where alarms go, how often to test them and when to replace them. State and local codes decide what is required in your buildings, and they are often stricter, so check them too. It is general information, not legal advice.
Why it is worth the routine
Carbon monoxide is the alarm that matters most at night, because it has no smell and its symptoms look like the flu: headache, dizziness, weakness, an upset stomach and confusion. The CDC counts more than 400 deaths a year in the United States from unintentional carbon monoxide poisoning not linked to fires, more than 100,000 emergency room visits and more than 14,000 hospital stays. CPSC puts more than 200 of the yearly deaths on consumer products, and more than 100 of those on portable generators.
For a manager, that turns into two habits: a CO alarm wherever fuel burns, and a clear message to tenants before storm season that generators never run indoors or in a garage.
Where alarms go
| Alarm | Where | Guidance from |
|---|---|---|
| Smoke | Inside every bedroom, outside each separate sleeping area, and on every level of the home, including the basement | NFPA |
| Smoke | On the ceiling or high on a wall; wall units no more than 12 inches below the ceiling | NFPA |
| Carbon monoxide | On each level of the home and outside sleeping areas; not in attics or basements unless someone sleeps there | CPSC |
| Both | Interconnected where possible, so when one sounds they all sound | NFPA and CPSC |
Testing and replacement
- Test every alarm once a month with the test button. CPSC recommends monthly tests for smoke and CO alarms.
- Replace batteries at least once a year in alarms that use replaceable batteries, or whenever an alarm chirps.
- Replace smoke alarms 10 years from the date of manufacture. The date is printed on the back. If there is no date, NFPA says to replace the alarm.
- Replace CO alarms on the manufacturer’s schedule, which is printed on the alarm and in its instructions.
Which alarms to buy
The U.S. Fire Administration describes three ways alarms are powered, and each one changes your replacement routine:
| Power | Test | Battery | Replace the alarm |
|---|---|---|---|
| Replaceable 9-volt battery | Monthly | At least once a year | Every 10 years |
| Sealed 10-year lithium battery | Monthly | Not replaceable | On the manufacturer’s schedule |
| Hardwired with a backup battery | Monthly | Backup at least once a year | Every 10 years |
Sealed long-life alarms remove the yearly battery visit, which is most of the chirping calls. USFA also recommends interconnected alarms, so when one sounds they all sound, and notes that alarms with strobe lights or vibration exist for people with hearing loss. If a tenant tells you someone in the home is deaf or hard of hearing, that is the alarm to put in.
Who tests what in a rental
Tenants are in the unit every day, so most leases ask them to test monthly and report problems. The landlord installs, replaces and checks at turnover. Write down which is which, and give tenants a simple way to report a dead or chirping alarm.
- At move-in: test every alarm with the tenant and record the result in the lease file
- At every make-ready: test, check the manufacture date and replace batteries
- At every visit to the unit: look for missing or disconnected alarms
- Once a year: replace batteries in alarms that use them
The chirping alarm call
A single chirp every minute or so usually means a low battery or an alarm at the end of its life. It is not a fire, but it should not wait a week either: a tenant who can’t sleep will pull the alarm off the ceiling, and then the unit has no alarm. Treat it as urgent, within a day. Ask the tenant for a photo of the alarm’s back label, so the technician brings the right battery or a replacement alarm.
A tenant who removed an alarm because it went off while cooking needs a working one back the same day, ideally a model designed to reduce nuisance alarms near kitchens.
Tell tenants what USFA tells everyone: never take the battery out while cooking. When steam or cooking sets it off, open a window or door, press the hush button and wave a towel at the alarm to clear the air. If it keeps happening, the fix is moving the alarm several feet further from the kitchen or bathroom, and that is your job, not theirs.
Texts to send
- At move-in: “Your home has smoke alarms in [rooms] and a CO alarm in [place]. Please press the test button once a month, and text us if one chirps or doesn’t beep.”
- Before winter: “Heating season starts this week. Please test your smoke and CO alarms today. Never run a generator, grill or camp stove indoors or in the garage.”
- After a chirping report: “Thanks. Please send a photo of the back of the alarm, so we bring the right battery or a new alarm. We’ll be there by [day, time] ET.”
The tenant text messages template has more texts in the same voice.
Where Now Ours fits
Ours answers tenant calls and texts at any hour and asks the safety questions you set. You decide what counts as an emergency, and everything else waits for the morning with the tenant told when to expect a call. Ours also books visits with tenants and your vendors or technicians.
Sources
- NFPA, Smoke alarm installation guide and safety tips: placement, monthly testing and 10-year replacement. Checked October 20, 2026.
- U.S. Fire Administration, Smoke alarms: maintenance by power type, interconnection, alarms for hearing loss and what to do when cooking sets one off. Checked October 20, 2026.
- CPSC, CO Alarms: placement on each level and outside sleeping areas. Checked October 20, 2026.
- CPSC, Carbon Monoxide Questions and Answers: battery backup and interconnected alarms. Checked October 20, 2026.
- CPSC, Carbon Monoxide Information Center: more than 200 consumer-product CO deaths a year, more than 100 linked to portable generators. Checked October 20, 2026.
- CDC, About carbon monoxide poisoning: more than 400 deaths, 100,000 emergency visits and 14,000 hospital stays a year. Checked October 20, 2026.