Why Your Gas Furnace Smells Like Gas When Starting Up
When your gas furnace starts up and you notice a smell that you think might be natural gas coming from your vents, it is natural to feel concerned. Even if the smell seems to fade after a short time, it still raises important questions about safety and normal furnace operation.
The smell you notice is not natural gas in its pure form. Gas suppliers across British Columbia add a chemical called mercaptan, which creates that unmistakable rotten-egg scent so homeowners can quickly recognize a possible leak.
When Gas Smells Are Normal
A brief warm or slightly dusty smell during furnace startup is often completely normal, especially if your system has been sitting idle during warmer months. Dust and debris naturally accumulate on the heat exchanger and burners when your furnace is not running. When the system fires up for the first time in autumn, this accumulated material burns off, creating a temporary smell that resembles gas.
This burn-off process typically produces a mild odour that fades within a short time, often within the first twenty to thirty minutes of startup. The smell should be relatively faint and should not intensify or spread strongly through your home. If you’re experiencing this type of brief, mild odour only during initial startup, your furnace is likely operating normally.
Older furnaces with pilot lights may also produce a very slight, brief gas-like smell right at the appliance during ignition. Modern electronic ignition systems have largely reduced this, but many homes across Vancouver Island still rely on older heating systems that can produce these short-lived smells.
When to Take Immediate Action
Strong, persistent, or intensifying gas odours signal potential danger and require immediate attention. If the smell doesn’t dissipate after thirty minutes, grows stronger during operation, or appears when your furnace isn’t running, you may have a gas leak.
Gas leaks can develop from faulty valves, damaged or loose gas connections, or problems in the burner or piping near your furnace. In British Columbia’s coastal climate, humidity and salt air can accelerate corrosion in heating systems, making these issues more common in older furnaces. Provincial gas safety regulations and local utilities emphasize taking immediate action if you suspect a gas leak.
If you detect a strong or persistent gas smell, evacuate your home immediately. Avoid using electrical switches, open flames, or anything that could create a spark. Once you’re safely outside, contact FortisBC’s emergency leak line at 1-800-663-9911 or call emergency services. Do not try to find or repair the leak yourself, adjust gas piping, or relight equipment until a licensed gas contractor or utility representative has told you it is safe. Don’t re-enter your home until professionals have declared it safe.
Pay attention to accompanying symptoms like headaches, nausea, or dizziness, which can be signs of carbon monoxide exposure from incomplete combustion. Older furnaces, especially those over fifteen years old, may be more susceptible to safety issues and benefit from annual professional maintenance to help ensure safe operation. Make sure carbon monoxide (CO) alarms are installed and tested regularly, and follow local code and manufacturer guidance on where to place them and when to replace them.
Keep Your Home Safe with Expert Gas Furnace Service
If you notice that your gas furnace smells like gas during startup, it’s crucial to address the issue promptly. At The Comfort Group, based on Vancouver Island, we offer professional gas furnace inspection and repair services. Our team of experts understands the unique challenges of heating systems in British Columbia’s coastal climate.
Don’t wait for problems to escalate. Regular maintenance ensures your furnace operates safely and efficiently. Schedule a gas furnace inspection on Vancouver Island today to help protect your home and family.