Today I’ll share the current requirements for carbon monoxide alarms in Minnesota, and I’ll also discuss some myths and misconceptions surrounding these devices.
Words matter
Before we get into the requirements, let’s start with definitions. First, let’s define carbon monoxide. It’s an odorless, invisible gas that can make people feel sick or tired at fairly low levels. At higher levels, it causes death. Unborn babies, kids, the elderly, and those with health conditions such as heart problems, respiratory problems, anemia, or sickle cell anemia are those at the highest risk.
Carbon monoxide is also known as CO. But never CO2. I hear people talk about CO2 alarms all the time, but CO2 is carbon dioxide, a natural component of the air that we breathe. Call it a CO alarm.
And on that topic, I’m specifically calling this a CO alarm, not a CO detector. They’re not the same thing. A CO alarm is a self-contained device with its own power supply and alarming method. A detector is part of another system, and may not contain its own alarm. It’s not the same thing.
Minnesota Residential Code requirements
Now that we have our terms defined, here are the residential code requirements for CO alarms in Minnesota, which can be found in section R315 of the MN Residential Code. This is my wording, so read the code if you want the exact language and full meaning. I’m simplifying things with my language.
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R315.1.1 (Listing) – CO alarms must be listed with UL 2034. This is an important detail to note, and I’ll come back to this shortly.
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R315.2.1 (New Homes) – CO alarms are needed in new homes that have fuel-fired appliances, or in homes with attached garages that also have a door between the house and garage.
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R315.2.2 (Existing Homes) – CO alarms must be added to existing homes with the same rules for new homes when pulling a building permit for work involving the interior of the home. This includes stuff like windows and doors but does not include things like roofing or siding. This also excludes permits for other trades, such as plumbing, electrical, or mechanical systems.
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R315.3 (Locations) – CO alarms must be installed outside and within 10’ of each bedroom. They must also be installed on the same level as each bedroom. If a fuel-fired appliance is located inside of a bedroom or its attached bathroom, you need a CO alarm inside the bedroom too.
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R315.4 (Combo Units) – Combination CO/smoke alarm units are fine.
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R315.5 (Interconnectivity) – CO alarms need to be set up so that when one goes off, they all go off. This can be done by wiring them together or installing units that talk to each other wirelessly. This isn’t required on existing homes if you have to bust open the walls to get at the wiring.
R315.6 (Power) – CO alarms need to be hardwired and have a battery backup. There are exceptions for homes that aren’t provided with a commercial power source (huh?), and for existing installations where you’d need to bust open the walls to do this. In those cases, battery power alone is fine. -
R315.7 (CO detection systems) – if you have a security system with carbon monoxide detectors, they need to comply with NFPA 720 and they can be used in lieu of CO alarms.
Minnesota Statutes
Besides the code requirements, we also have the Minnesota Statutes to think about. Sections 299F.50 and 299F.51 give us a few more requirements.
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299F.50 Subd. 8 (Installed) – CO alarms may be hardwired, plugged into an unswitched outlet, or attached to a wall if battery powered.
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299F.51 Subd. 1 (Required) – CO alarms are required within 10’ of each bedroom. Note that this requirement has nothing to do with permits, remodels, real estate transactions, inspections… none of that. They’re required, period.
The rest of the Minnesota statutes mostly pertain to responsibilities for multifamily dwelling unit owners and occupants.
Important notes
Carbon monoxide alarms are life-safety devices. UL standards for CO alarms aren’t designed to keep us healthy. They’re designed to keep us alive. In fact, according to CO Experts, CO alarms won’t sound off at levels below 30 ppm, and even digital displays must show “0” below 30 ppm! If a UL listed alarm detects levels between 30 ppm and 69 ppm for 30 days straight (thirty in a row, not 30 cumulative), it may sound off. Less than that? Nothing. For perspective, people will experience headaches and dizziness from six to eight hours of exposure at 35 ppm. Is the weight of this sinking in? There are a lot of homes at risk from carbon monoxide, yet they have a false sense of security because they have a CO alarm installed.
For this reason, I’m a big fan of low-level CO monitors. These are devices designed to alert us to much lower levels of CO than UL listed alarms. They’re way more expensive and they’re not a substitute for the CO alarms required by code… but they’re a smart thing to have in your house. Check out CO Experts, Kidde, or Defender for a few examples of these.
Reuben’s nightstand
Also, be aware that CO alarms have a limited life. Older Kidde CO alarms were good for seven years, but new ones are good for ten years. First Alert CO alarms used to be good for five years, but now that they’re incorporated with smoke alarms, they’re typically good for ten years too. If you don’t know the age of your CO alarm and it could be over five years old, replace it. Most CO alarms have the date somewhere on the back.
When installing a CO alarm, follow the manufacturer’s instructions for location. It’s fine to install CO alarms on the ceiling or a wall. Even low on a wall. Manufacturers don’t have restrictions like they do for smoke alarms, so they can be installed where convenient.
And finally, CO alarms requirements have nothing to do with a real estate transaction. I’ve heard many a well-meaning parent tell their adult kids about how CO alarms are required by law when you sell a home in Minnesota, with the idea that their kid ought to make the seller repair this $13 defect on the home they’re buying. I’m sorry, but there is no such requirement tied to real estate.
Author: Reuben Saltzman, Structure Tech Home Inspections
