Safety boundary: If a carbon-monoxide alarm sounds or occupants have possible exposure symptoms, leave immediately for fresh air and call 911 or the local fire service. Do not re-enter until cleared.
Why heating season matters
Fuel-burning furnaces, boilers, water heaters and fireplaces can produce carbon monoxide when they malfunction, are poorly vented or lack proper combustion air.
Alarms are essential
Use alarms certified for Canada and place them according to provincial or territorial requirements and manufacturer instructions. Test and replace them as directed.
Alarms do not replace maintenance
A detector warns of a problem; it does not make an unsafe appliance safe. Venting and fuel-burning equipment need correct installation and maintenance.
Prevent outdoor sources entering
Never operate generators, barbecues or fuel-burning equipment inside homes, garages or sheds. Keep them away from doors, windows and air intakes.
Useful questions to record
- Can everyone leave safely now?
- Which emergency service or utility should be called from outside?
- What information can be recorded without re-entering?
Related guides
Gas Odour or Suspected Fuel LeakA simple emergency response that avoids switches, sparks and delay.Venting and Combustion AirWhy appliance vents, chimneys, exhaust fans and house pressure interact.HVAC, Filtration and Indoor Air QualityWhat central HVAC can contribute—and what requires source control or ventilation.Smoke and Carbon-Monoxide Alarm ChecklistA practical record for alarm locations, testing and replacement dates.