Carbon Monoxide and HVAC: Safety Essentials

Carbon monoxide (CO) is called the silent killer because you can't see, smell, or taste it. HVAC equipment can be a source.

What Produces CO

Combustion Equipment Any fuel-burning appliance can produce CO: - Gas furnaces - Gas water heaters - Gas boilers - Gas fireplaces

Normal Operation Properly functioning equipment produces CO but vents it safely outside.

Dangerous Conditions CO enters living spaces when: - Heat exchangers crack - Venting is blocked or damaged - Combustion is incomplete - Back-drafting occurs

Warning Signs

Physical Symptoms - Headache - Dizziness - Nausea - Confusion - Shortness of breath

Symptoms often improve when leaving the house.

Equipment Signs - Yellow or orange furnace flame (should be blue) - Soot around the furnace - No draft in chimney - Excessive moisture on windows - Rust on flue pipes

If You Suspect CO

1. Get everyone out immediately 2. Call 911 from outside 3. Don't re-enter until cleared by professionals 4. Seek medical attention if symptomatic

Prevention Measures

CO Detectors - Install on every level - Place near bedrooms - Test monthly - Replace batteries annually - Replace detectors every 5-7 years

California law requires CO detectors in homes with fuel-burning appliances.

Annual Maintenance Professional furnace maintenance includes: - Heat exchanger inspection - Combustion analysis - Venting verification - Safety control testing

Proper Venting - Keep vents clear of blockages - Don't modify venting - Ensure adequate combustion air supply

High-Risk Situations

Cracked Heat Exchangers Cracks allow combustion gases into air stream. More common in: - Older furnaces - Oversized systems (frequent cycling) - Neglected equipment

Blocked Venting Bird nests, debris, or damage can block exhaust. Annual inspection catches this.

New Construction/Remodeling Tightening a home without addressing combustion air can cause back-drafting.

The Bottom Line

CO detectors are essential and inexpensive. Annual HVAC maintenance is the best prevention. Take any CO detector alarm seriously—get out and call for help.