Can I still use my damper after installing a gas insert in my Calgary fireplace?

No, you should not use your existing damper after installing a gas insert. The damper should be permanently secured in the open position or removed entirely, and the gas insert will be connected to a new flexible liner that runs up through your existing chimney.

When a gas insert is installed in your existing masonry fireplace, it creates a completely new venting system. The insert connects to a flexible aluminum or stainless steel liner that's fed down from the top of your chimney and runs all the way up to terminate at the chimney crown. This liner becomes the dedicated flue for your gas insert, bypassing your original damper entirely.

Your original damper becomes obsolete and potentially dangerous if left functional. If you accidentally closed the damper while operating the gas insert, you'd block the exhaust path for combustion gases, creating a serious carbon monoxide hazard. Most Calgary fireplace installers will either remove the damper mechanism completely or permanently secure it in the open position with clamps or brackets to prevent accidental closure.

The new liner system actually provides better performance than your original setup. Gas inserts in Calgary typically use 5-inch or 6-inch flexible liners that create proper draft and prevent condensation issues that can occur when undersized gas appliances use oversized masonry flues. The liner also protects your existing chimney from acidic condensation that gas combustion produces, which can deteriorate mortar joints over time.

This work requires a gas permit from the City of Calgary and must be performed by a licensed gas fitter. The Safety Codes Officer will inspect the completed installation, including verifying that the liner is properly sized, connected, and terminated, and that the original damper has been properly secured or removed. The inspector will also check that the insert maintains proper clearances and that carbon monoxide detectors are installed.

During Calgary's chinook events, the new liner system actually provides more consistent draft than the original large masonry flue, which could experience draft reversals during rapid pressure changes. The smaller, dedicated liner maintains steadier airflow for reliable gas insert operation.

If you're considering a gas insert for your existing masonry fireplace, expect the complete project to cost $3,000-$6,000 in Calgary, including the insert unit, liner installation, gas line connection, permits, and finishing work around the surround. The efficiency upgrade from 10-15% (open masonry) to 70-85% (gas insert) makes this one of the most cost-effective fireplace improvements for Calgary's long heating season.

Need help finding a gas insert installer? Calgary Fireplaces can match you with local contractors who specialize in fireplace conversions and can handle the permit process from start to finish.