Most homeowners assume a carbon monoxide detector is just a good idea. In Colorado, for most homes, it is also the law. Right around the time furnaces fire back up for the season is a good moment to confirm you are actually meeting that requirement, not just assuming a detector installed years ago still counts.

The Law: Colorado House Bill 1091

Since July 1, 2009, Colorado law has required a working carbon monoxide alarm in dwellings that are built, sold, remodeled, or rented under specific conditions. Not every home in the state is covered by the letter of the law, but in practice it covers nearly every home in the Denver metro, since gas heat is the default here.

Which Homes Are Covered

The requirement applies to a home that has a fuel fired appliance, such as a gas furnace or gas water heater, or an attached garage. That combination describes the overwhelming majority of houses across the metro area, which is why this law affects far more homeowners than most people realize.

Where the Detector Has to Go

Colorado law requires a working detector within fifteen feet of the entrance to each room used for sleeping, not just anywhere in the house. A single detector in a basement or hallway does not necessarily satisfy this if it sits outside that range of one or more bedrooms.

What This Means If You Rent

At the start of every new tenancy, the landlord is responsible for making sure a required detector is present, working, and supplied with batteries. If a tenant reports a detector missing or not working during their tenancy, replacing it is the landlord’s responsibility, not something a tenant is expected to handle on their own.

What This Means If You Own

For most owner occupied homes, the responsibility falls directly on the homeowner, and it becomes a checkpoint again at resale, since the law also applies at time of sale. Practically, it is worth treating this as an annual habit rather than a box you checked once, since both the batteries and the sensor itself have a limited lifespan.

Why Fall Furnace Startup Is a Natural Checkpoint

When your furnace turns on for the first time since spring, that is also a natural moment to confirm the detector required near your bedrooms is actually present and working, not just installed at some point in the past and forgotten about since.

Serving the Denver Metro

We perform fall furnace and carbon monoxide safety inspections for homeowners across Denver, Aurora, Lakewood, Westminster, Thornton, Centennial, Broomfield, Parker, Highlands Ranch, Commerce City, Littleton, Wheat Ridge, Brighton, Englewood, Arvada, Golden, Castle Rock, Greenwood Village, and Northglenn.

Frequently Asked Questions

Does Colorado law require a carbon monoxide detector in every single home? The requirement is tied to specific conditions, primarily a fuel fired appliance or an attached garage, but that describes most homes in the Denver metro, so in practice it covers nearly everyone.

Does the law apply to homes without a gas furnace? It can still apply if the home has another fuel fired appliance, such as a gas water heater, or an attached garage, even without gas heat.

How many carbon monoxide detectors does a home need? Enough to have a working detector within fifteen feet of the entrance to every room used for sleeping, which often means more than one unit in a larger home.

Whose responsibility is it to replace a detector in a rental? The landlord, both at the start of a new tenancy and any time during the tenancy if a tenant reports the detector missing or not working.

Does a smoke detector satisfy the carbon monoxide requirement? No. A standard smoke detector does not sense carbon monoxide at all, so a separate carbon monoxide detector, or a combination unit rated for both, is required.

Do Not Wait Until December to Find Out

If it has been a while, get it looked at before you are relying on it in December.

Book a fall safety check this week