Carbon monoxide (CO) is called the silent killer for a reason - it's colorless, odorless, and can be fatal. Your gas furnace is a potential source of CO, which is why understanding the risks and prevention is critical for Ottawa homeowners.
Here's what you need to know about carbon monoxide and your heating system.
How Furnaces Produce Carbon Monoxide
Normal operation: When gas burns completely, it produces carbon dioxide (CO2) and water vapor - harmless byproducts vented outside.
Dangerous operation: When combustion is incomplete (not enough oxygen, dirty burners, cracked heat exchanger), carbon monoxide is produced instead.
The risk: A cracked heat exchanger or blocked vent can allow CO to enter your home's air supply instead of being vented outside.
This is why annual furnace maintenance matters - technicians check for these exact issues.
Warning Signs of CO Problems
Furnace warning signs: - Yellow or orange burner flame (should be blue) - Soot or black marks around furnace - Excessive condensation on windows - Rust on vent pipe or chimney - Furnace runs constantly but doesn't heat well - Pilot light frequently goes out
Health symptoms (can mimic flu): - Headache - Dizziness - Nausea - Confusion - Shortness of breath - Symptoms improve when you leave the house
If multiple family members have flu-like symptoms that improve when away from home, suspect CO immediately.
CO Detector Requirements and Placement
Ontario law requires CO detectors: - Outside all sleeping areas - On every level with fuel-burning appliances - Near attached garages
Best practices: - Install at breathing height (5 feet from floor) - Don't place near windows, doors, or bathrooms - Test monthly, replace batteries annually - Replace detectors every 7-10 years
Types of detectors: - Battery-powered: $25-$40 (replace batteries annually) - Plug-in with battery backup: $30-$50 - Hardwired: $100-$200 installed - Combination smoke/CO: $40-$60
Interconnected detectors (when one alarms, all alarm) provide the best protection.
What to Do If CO Detector Alarms
If your CO detector goes off:
- Don't ignore it - treat every alarm as real
- Get everyone outside immediately - including pets
- Don't try to find the source - get out first
- Call 911 from outside - fire department will assess
- Don't re-enter until cleared by professionals
- Get checked medically if anyone has symptoms
After the incident: - Don't turn furnace back on until inspected - Have HVAC technician check heat exchanger - Have plumber check water heater - Check all fuel-burning appliances
False alarms are rare - most alarms indicate real CO presence, even if levels seem low.
Prevention Through Maintenance
Annual furnace maintenance includes: - Heat exchanger inspection (visual and camera) - Burner cleaning and adjustment - Combustion analysis (measures CO in flue gases) - Vent pipe inspection - Safety control testing
Cost of annual maintenance: $150-$250 Cost of heat exchanger replacement: $1,500-$3,000 Value of your family's safety: Priceless
Red flags during maintenance: - Technician finds cracks in heat exchanger - Combustion analysis shows elevated CO - Flame rollout detected - Pressure switch problems
If cracks are found: Replace the heat exchanger or furnace. Do not operate the furnace until repaired.
The Bottom Line
Carbon monoxide risks are real but preventable. Install CO detectors on every level, get annual furnace maintenance, and know the warning signs. A $200 annual maintenance visit can prevent a tragedy.
Due for a furnace safety inspection? Contact us to schedule - we check every potential CO source during our maintenance visits.
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