For best protection, install smoke detectors on every level of your home, inside each bedroom, and outside every sleeping area. Carbon monoxide detectors belong on every level, near sleeping areas, and within 10–15 feet of any fuel-burning appliance like a furnace, water heater, or gas range. In Colorado, where attached garages are common and furnaces run hard through long winters, CO protection is especially important — and combination smoke/CO units are a practical choice for most rooms.

Smoke Detector Placement Rules

The National Fire Protection Association (NFPA 72) sets the baseline standard most Colorado jurisdictions adopt:

  • One smoke detector inside every bedroom.
  • One outside each separate sleeping area (e.g., in the hallway serving the bedrooms).
  • At least one on every level of the home, including the basement.
  • On ceilings or high on walls (within 12 inches of the ceiling).
  • Keep smoke detectors at least 3 feet from HVAC supply vents and away from kitchens where cooking steam could trigger nuisance alarms.

Carbon Monoxide Detector Placement

CO is colorless and odorless — detectors are the only reliable way to catch it. Colorado law requires CO detectors in new construction and during certain renovation permits. Best practice for existing homes:

  • Install a CO detector on every level of the home.
  • Place one near (but not directly next to) each sleeping area so it can wake occupants at night.
  • Install within 10–15 feet of fuel-burning appliances: furnace, boiler, water heater, gas range, fireplace.
  • If you have an attached garage, put a CO detector in the adjacent room — car exhaust and idling engines are a common CO source.

Why Colorado Homeowners Face Elevated CO Risk

At 5,280 feet, combustion appliances run with slightly less oxygen than at sea level. A furnace or water heater with a cracked heat exchanger, blocked flue, or poor combustion can produce elevated CO levels more readily than it might at lower altitudes. Attached garages — common in suburban Denver, Aurora, and Lakewood homes — are another risk factor. And during winter, homes are sealed up tight, which reduces natural ventilation and allows any CO produced indoors to accumulate faster.

Smart and Interconnected Detectors

Older battery-only detectors are still functional, but interconnected detectors — whether hardwired or wireless smart units — offer a significant safety upgrade. When one alarm triggers, all alarms in the home sound simultaneously, giving occupants in remote bedrooms maximum warning time. Smart models send alerts to your phone when you’re away, which is valuable for vacation homes or rental properties. Done!’s licensed electricians install hardwired and smart smoke and CO detector systems properly, including ensuring they’re on the right circuits and correctly interconnected.

Maintenance and Replacement

Smoke and CO detectors have a limited service life — most manufacturers recommend replacing smoke detectors every 10 years and CO detectors every 5–7 years. Test every unit monthly and replace batteries annually (or install 10-year sealed battery units to eliminate the annual chore). If a detector chirps continuously and a new battery doesn’t fix it, the unit has likely reached end of life.

Need to upgrade or add detectors to your home? Done!’s electricians handle smoke detector and CO detector installation across the Denver metro. For peace of mind on your heating equipment specifically, our furnace maintenance service includes a heat exchanger check — one of the most important CO-related safety inspections a homeowner can schedule.