Where does Minnesota law require carbon monoxide alarms?
Minnesota Statutes 299F.51 requires an approved, working carbon monoxide alarm within 10 feet of each room lawfully used for sleeping, in every single-family home and apartment unit. "Approved" means certified to UL 2034. That's the legal minimum. We'd also put one on every level, including the basement near the furnace and water heater.
Key points
- The law: an approved CO alarm within 10 feet of every room used for sleeping (Minn. Stat. 299F.51).
- Good practice: one on every level, including the basement and near the door from an attached garage.
- Keep alarms out of bathrooms and garages, and away from fuel-burning appliances, vents, fans and windows.
- The Minnesota Department of Health says CO alarms typically last 5 to 7 years, depending on the manufacturer.
- If a CO alarm sounds, get everyone outside and call 911 from there. Don't go back in to find the cause.
Minnesota law (Minn. Stat. 299F.51) requires an approved, working carbon monoxide alarm within 10 feet of every room used for sleeping, in every single-family home and every apartment unit. That's the minimum. We'd also put one on every level, including the basement, and one on the house side of the door from an attached garage. CO has no color and no smell, a Minnesota house burns fuel six or seven months a year, and the Minnesota Department of Health notes that CO poisoning cases run higher in winter. A working alarm in the right place is the only way you'll know.
What does Minnesota law require for carbon monoxide alarms?
Minnesota Statutes 299F.51 says every single-family dwelling and every unit in a multifamily building must have an approved and operational carbon monoxide alarm installed within 10 feet of each room lawfully used for sleeping. Hotel and lodging house guest rooms need one in each sleeping room.
A few details from the statute and its definitions in 299F.50:
- Approved means certified by a recognized testing lab to UL 2034, the standard for residential CO alarms. Look for it on the package or the back of the alarm.
- Installed means hardwired, plugged directly into an outlet that isn't on a switch, or, if battery-powered, attached to the wall.
- Disabling is prohibited. Nobody may pull the batteries from a required alarm or otherwise make it inoperable.
- Rentals: in multifamily buildings, the owner provides and installs the alarms and replaces any that went missing or stopped working during a prior tenancy. The tenant keeps them in good repair while living there.
The rule is written per sleeping room, so one hallway alarm can cover several bedrooms as long as it's within 10 feet of each door.
Placement at a glance
| Spot | Law or advice | Notes |
|---|---|---|
| Within 10 feet of every sleeping room | Required by law | One hallway alarm can cover several doors |
| Every level, including the basement | Our advice | Living area or foot of the stairs, not against the furnace |
| House side of the attached-garage door | Our advice | Cars warming up in winter are a common source |
| Finished basement bedroom by the mechanical room | Required if it's used for sleeping | Inside or right outside the room |
| Cabin, fish house or anywhere a propane heater runs | Our advice | A battery alarm is cheap insurance |
| Bathroom or garage | Avoid | Steam affects the sensor; garages false-alarm |
| Right beside a furnace, water heater, range or fireplace | Avoid | Follow the minimum distance in the instructions |
Where else should you put a CO alarm?
The law sets a minimum. From what we see in basements, we'd add:
- One on every level, including the basement. Put it in the living area or at the bottom of the stairs, not right against the furnace or water heater.
- Near the door from an attached garage, on the house side.
- In or right outside a finished basement bedroom that shares a wall with the mechanical room.
- At the cabin and in the fish house, anywhere a propane heater runs in a small, tight space.
Combination smoke and CO alarms are fine as long as the CO side is listed to UL 2034 and the unit's instructions allow the spot you've picked. Newer houses often have hardwired, interconnected alarms, so when one sounds they all do.
How high should a carbon monoxide alarm be mounted?
CO mixes with room air rather than pooling at the floor or ceiling, which is why manufacturers approve wall, ceiling and plug-in mounting. Follow the height and location in your alarm's instructions. For a plug-in unit, use an outlet that isn't hidden behind a couch or curtains.
Keep alarms out of:
- Bathrooms, where steam and humidity can affect the sensor.
- The garage itself, where it will false-alarm.
- Spots right next to a furnace, water heater, range or fireplace. Your alarm's instructions list a minimum distance from fuel-burning appliances.
- Drafty places: next to supply registers, ceiling fans, windows and exterior doors, where moving air can delay a reading.
- Unheated spaces outside the alarm's rated temperature range, like a three-season porch in January.
How often should you test and replace CO alarms?
Press the test button monthly. That confirms the horn and circuit work, but it doesn't prove the sensor still reads CO accurately, so the age of the alarm matters too. The Minnesota Department of Health says CO alarms typically last 5 to 7 years, varying by manufacturer (MDH on carbon monoxide). The replace-by date is printed on the alarm, and many newer ones chirp at end of life. Write the install date on each alarm with a marker so you don't have to guess. A good time to check them all is the day you turn the furnace on for the first time in fall.
Know your alarm's sounds. Most CO alarms signal with four quick beeps and a pause. A single chirp every minute or so usually means a weak battery or end of life. If you're ever unsure which you're hearing, treat it as an alarm.
If a CO alarm goes off
- Get everyone out into fresh air, including pets.
- Call 911 from outside or from a neighbor's. If you also smell gas, call your gas utility's emergency line from outside, and don't flip switches on the way out.
- Stay out until the fire department clears the house.
- Before anyone runs the furnace, water heater or other fuel-burning appliances again, have the source found and fixed.
MDH lists early CO symptoms as mild headache and breathlessness with moderate exertion, then worse headaches, dizziness, fatigue and nausea. Alarms built to UL 2034 are designed not to sound at low levels, to avoid false alarms. If people in the house feel sick and better once they leave, act on that even if the alarm is quiet.
Where does carbon monoxide come from in Minnesota houses?
When we trace a CO call, these are the usual suspects:
- The furnace. Poor combustion, a disconnected or rusted vent pipe, or a cracked heat exchanger. A technician who finds an unsafe furnace can red-tag it, meaning it's shut off until repaired.
- A blocked PVC vent. High-efficiency furnaces vent out a side wall, where drifting snow and ice can seal the pipe during a cold snap. See our guide to clearing a frozen furnace vent.
- A backdrafting water heater. After an 80% furnace is replaced with a condensing one, a gas water heater can be left alone in a chimney that's now too big for it. Our AFUE explainer covers why that liner matters.
- The attached garage, a generator or a fireplace. Winter storms bring outages, and outages bring generators. Never run one in the garage or near a window, even with the door open.
Signs to call a technician, even without an alarm
- Soot or scorch marks around the furnace burners or the water heater's draft hood
- A yellow, lazy or floating burner flame; a healthy gas flame is mostly blue
- A vent pipe that's loose, rusted through or pulled apart at a joint
- Headaches or nausea that ease when you leave the house
- A furnace that runs, shuts down and relights over and over on the coldest nights
Any of these gets a furnace looked at before the next cold snap. An annual furnace tune-up is where most of this gets caught: we check the venting, the flame and the combustion before the heating season starts. Our page on furnace maintenance in Minneapolis covers what that visit looks like in older city houses, where the furnace and water heater often share one chimney.
What it costs
CO alarms themselves are sold at any hardware store, and in apartment buildings the owner provides them. Our furnace tune-up starts at $129, and $219 covers the furnace and AC on one visit. If an alarm went off and the fire department has cleared the house, or you suspect the furnace, call us for furnace repair; in Saint Paul, see furnace repair in Saint Paul. The $79 trip charge is waived when you approve the repair, and no-heat calls get priority.
What to do next
Walk the house with a tape measure and check that every bedroom door is within 10 feet of an alarm, then read the date on each one. For how smoke detection ties into the HVAC system, see our post on integrated smoke detection. Call 612-429-3465, any day from 7am to 9pm.
Questions
Can one hallway alarm cover several bedrooms?
Yes, if it's within 10 feet of each bedroom it's meant to cover. The law is written per sleeping room, so measure from each bedroom door. A central hallway alarm often covers two or three bedrooms. A bedroom at the far end of the house, over the garage or on another floor usually needs its own.
Do I need a CO alarm if my house is all-electric?
Yes. Minnesota's statute applies to every single-family home, and it has no exception for houses without gas. The exemption for minimal carbon monoxide sources is limited to multifamily building owners who certify it to the state. An attached garage, a fireplace or a generator during an outage can all put CO in an all-electric house anyway.
How do I know if my CO alarm is too old?
Look for the replace-by or manufacture date on the back. The Minnesota Department of Health says CO alarms typically last 5 to 7 years, varying by manufacturer, and many newer alarms chirp at end of life. The test button checks the horn and circuit, not whether the sensor still reads CO accurately, so the date matters.
My CO alarm is chirping. Is that an emergency?
A single chirp every minute or so usually means a low battery or an alarm at end of life. A real CO alarm is a loud, repeating pattern, most commonly four quick beeps and a pause. Your alarm's label explains its signals. If you can't tell which one you're hearing, treat it as an alarm: get everyone out and call 911.
Sources
- Minnesota Statutes 299F.51 revisor.mn.gov
- MDH on carbon monoxide health.state.mn.us