Carbon monoxide alarm requirements for Minnesota, including the little details

Carbon monoxide alarms are required in just about every type of dwelling in Minnesota, and it’s been this way for several years now, but there is still a lot of confusion about this requirement.

General Requirement - This text comes directly from Minnesota Statute 299F.50:

Every single family dwelling and every dwelling unit in a multifamily dwelling must have an approved and operational carbon monoxide alarm installed within ten feet of each room lawfully used for sleeping purposes.

One and one half story houses: a carbon monoxide alarm installed on the first floor within ten feet of the stairway to the second floor does not count as being installed within ten feet of the second floor bedroom.  The second floor bedroom will generally begin at the top of the stairway, not the bottom.

What constitutes ten feet: Measure from the door of the sleeping room to the carbon monoxide alarm.  If you have to pass through a wall, floor, ceiling, or doorway with a door that can be closed, it doesn’t count.

How this law gets enforced: For the most part, it doesn’t.  Building inspection departments may notify homeowners that carbon monoxide alarms are required, but the intent of this law wasn’t to make building inspection departments enforce carbon monoxide alarms (although many still do).   The exception to this is Minneapolis and South Saint Paul; both of those cities require carbon monoxide alarms for their Truth-in-Sale of Housing programs.

Definition of “installed”: this text comes directly from the Minnesota statute:

“Installed” means that an approved carbon monoxide alarm is hard-wired into the electrical wiring, directly plugged into an electrical outlet without a switch, or, if the alarm is battery powered, attached to the wall of the dwelling.

While the official definition doesn’t mention mounting the detector on the ceiling, that’s ok too. If a carbon monoxide alarm is sitting on someone’s desk, it’s not installed.  I’ve actually had several homeowners try to convince me otherwise.

When to replace: Approximately 99.3% of the CO alarms that I come across are made by Kidde or First Alert.  Kidde CO alarms last seven years, while First Alert CO alarms last five years.  You won’t find that information published on either of their web sites though; you actually need to call them to get that info.

Where to mount carbon monoxide alarms: follow the installation instructions from the manufacturer.  In general, carbon monoxide alarms can be mounted high or low on the walls, as long as children can’t mess with them.

The CO alarm pictured above was actually hanging from a cable jack on the wall of a kid’s toy room; I’d consider that a poor location.

Reuben Saltzman, Structure Tech Home Inspections - Email- Home Inspections in Minnesota

    

Houses Don't Need CO2 Alarms

There are many common misconceptions about furnaces, water heaters, and carbon monoxide that I hear repeated on a daily basis, and I’d like to clear a few of them up.


False: Carbon Monoxide is also called CO2.  Carbon Monoxide is CO. Carbon Dioxide is CO2.  (Mono = 1, Di = 2)


False: Cracked heat exchangers create CO.  CO is caused by incomplete combustion, period.  A cracked heat exchanger does not create CO.  A heat exchanger is the part of a furnace that transfers heat from the flames to the household air.  A functional heat exchanger keeps the household air and the combustion gases completely separate from each other.  If a furnace has a cracked heat exchanger, the combustion gases can mix with the household air.  It’s usually just a little bit, but this is still unacceptable, and it means the furnace or heat exchanger should be replaced.  The photos below show cracks in heat exchangers (click the photos for full-sized images).

   

False: Cracked heat exchangers can be fixed.  They can’t be fixed.  The heat exchanger or entire furnace needs to be replaced.



False: High CO levels = cracked heat exchanger.  See above.  We test the CO levels in the flue gas, which has nothing to do with a cracked heat exchanger.  Heat exchangers fail when the metal rusts through or when it cracks.  CO does not cause this.


False: High CO levels in the flue gas mean the furnace is leaking CO.  If there is a high level of CO in the flue gas, there is a potential for the exhaust gases to mix with the household air, or ‘leak’.  One way would be for the exhaust gases to backdraft, which means that instead of rising up and out of the house, they come back down the flue.  The other way would be because of a cracked heat exchanger.  If we find high levels of CO in the flue gas, we recommend immediate repair – it doesn’t matter if the gases are mixing with the household air at the time of the inspection or not, because this condition could potentially change at any time.  Higher CO levels can often be fixed.


False: Backdrafting at a furnace or water heater means CO is coming in to the home.Backdrafting means that exhaust gases are spilling back in to the home, rather than going up the flue.  A properly functioning water heater or furnace will not create CO, so you can’t say CO is coming in to the home unless you test the exhaust gases; we do this at every inspection.  Click here to see a video of me inspecting a furnace.  While backdrafting doesn’t mean CO is coming in to the home, this is still a potentially hazardous situation that requires immediate correction.  Backdrafting has the potential to allow CO in to the home, and will always contain CO2 (carbon dioxide), which can cause sickness and headaches in higher concentrations.

Wrong Term: Hot water heater.  Just 'water heater'.  The heated water that comes out is hot.
To summarize, high levels of CO need to be fixed, cracked heat exchangers need replacement, and backdrafting is never ok.  These three things are all independent, but a combination of these conditions is especially dangerous.  When using these terms, make sure you have them correct.  It makes a difference.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspections

RELATED POST: Commonly Mistaken And Mis-Used Terms, Part II

Carbon Monoxide Alarm Requirements For Minnesota

Carbon monoxide alarms have been required in new homes in Minnesota since January 2007, and have been required in existing single family homes since August 1st, 2008.  CO alarms need to be installed within ten feet of every room lawfully used for sleeping purposes.  "Installed” means hardwired, plugged in to an outlet, or attached to the wall if battery operated.

Because the requirement for CO alarms is a Minnesota Statute (not a rule), the requirements for CO alarms will not be enforced by building officials - although some may choose to enforce them anyways.
The cities of Minneapolis and South Saint Paul enforce the requirement for CO alarms through their Truth-in-Housing programs.  The cities of Saint Paul and Maplewood require evaluators to list missing CO alarms as a hazard, but homeowners do not need to fix this hazard.

To keep current with today’s requirements and to keep your home safe, I recommend upgrading to today’s standards.   I have hardwired, interconnected smoke detectors throughout my home, so I replaced two of the hardwired smoke detectors with combination smoke and carbon monoxide alarms.  Of all the ways to install a carbon monoxide alarm, this is the most difficult, but it only takes about 15 minutes.

The full requirements for carbon monoxide alarms can be found at Minnesota Statute 299F.50

Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspections