Carbon monoxide from a malfunctioning gas furnace is one of the most serious home safety risks. Greater Vancouver homeowners need to know the warning signs — because CO has no odour, colour, or taste.
HeatLand Heating & Cooling provides expert furnace diagnosis across Greater Vancouver.
Call (604) 330-3812 Get a Free QuoteWhat This Symptom Means
Carbon monoxide is produced when natural gas combustion is incomplete. A properly operating furnace vents all combustion gases to the outside. Problems arise when the heat exchanger cracks, the venting is blocked, or combustion is running rich — allowing CO to enter the living space.
Common Causes
- Cracked or failed heat exchanger allowing combustion gases into the air stream
- Blocked flue vent preventing combustion gases from exiting the home
- Backdrafting — negative pressure in the home drawing flue gases back inside
- Incomplete combustion from a dirty burner or incorrect gas pressure
- Running gas appliances in enclosed spaces without adequate ventilation
What Homeowners Can Check Safely
- Install CO detectors on every floor of the home, especially near bedrooms and the furnace room
- If CO alarm sounds, leave immediately, leave the door open, call 911, and do not re-enter until cleared by emergency services
- Watch for health symptoms: headaches, nausea, dizziness, confusion — particularly in multiple household members simultaneously
When to Call a Licensed Technician
Some furnace issues require a licensed HVAC technician. Do not attempt to open gas lines, replace internal components, or reset persistent lockouts without professional diagnosis.
- Annual combustion safety inspection of the furnace
- Flue and venting inspection
- Heat exchanger inspection with borescope
- Combustion gas analysis measuring CO in the air stream
- CO detector installation and placement guidance
Frequently Asked Questions
How many CO detectors do I need in my home?
BC Fire Code recommends CO detectors adjacent to all sleeping areas. A practical approach is one on each floor of the home, with one in the basement near the furnace area. Detectors should be replaced every 5–7 years — they have a limited sensor life even if never triggered.
Can a furnace produce CO even if it has been running fine for years?
Yes. A heat exchanger that has been under thermal stress from filter neglect, short cycling, or age can develop a crack at any time. Annual furnace maintenance that includes combustion safety inspection is the most reliable way to catch this before it becomes a household emergency.
If your furnace is showing these signs, HeatLand can help. We serve homeowners across Greater Vancouver.
Call (604) 330-3812 Book a Furnace Check