A gas appliance smells like exhaust in my Abbotsford home, is that dangerous?

Yes, exhaust smell from a gas appliance is a serious warning sign and you should treat it as a potential carbon monoxide (CO) hazard until proven otherwise.

What to Do Right Now

If the smell is strong, you notice symptoms like headache, dizziness or nausea, or a CO alarm has sounded, leave the building immediately and call emergency services from outside. Do not go back in to open windows or turn anything off.

If the smell is faint and intermittent and no one feels unwell, you can ventilate the space and shut the appliance off at its switch or thermostat, but still get it inspected before running it again. A CO alarm on every level of the home, and within 5 metres of each bedroom door, is strongly recommended for any home with a fuel-burning appliance.

Exhaust odour almost always means combustion gases are escaping into the living space instead of venting outside. Common causes include a cracked heat exchanger in a furnace, a blocked or deteriorating flue, a backdrafting chimney, a failed draft inducer, or a shared vent that is undersized after one appliance was removed or upgraded. Older Abbotsford homes with a gas furnace and a gas water heater sharing a single masonry chimney are particularly prone to backdrafting, especially after a high-efficiency furnace was added and the original chimney became too large for the remaining appliance.

Abbotsford sits outside Metro Vancouver, so it falls under the Fraser Valley Regional District and Technical Safety BC handles both gas permits and inspections for residential work there. Any contractor doing the diagnostic or repair work must be employed by a gas contractor licensed with Technical Safety BC. You can search the licence registry on the Technical Safety BC website to confirm before anyone touches the appliance.

A proper inspection should include a combustion analysis, a heat exchanger check (often with a camera), a flue pressure and draft test, and a CO reading at the registers and near the appliance. The technician should also check whether the venting configuration still meets current requirements, particularly if any appliances have been changed since the home was built.

Repair costs vary depending on what is found: a service call and diagnostic typically runs $120 to $250, a flue repair or reline can run considerably more, and a cracked heat exchanger usually means furnace replacement, which in Metro Vancouver and the surrounding region runs $5,500 to $11,000 for a high-efficiency gas unit installed.

Do not run the appliance again until a licensed gas contractor has cleared it in writing. Ask for a written report naming the fault found, the repair completed, and confirmation that combustion and venting tested within safe limits after the work. Once you have that, Vancouver HVAC Pro can match you with local HVAC contractors for free if you need quotes for the repair or a replacement system.