Gas Fitter Test 2026 – 400 Free Practice Questions to Pass the Exam

Installing a metal chimney liner is considered an acceptable option when a fireplace insert is installed. This is because metal chimney liners are designed to withstand the high temperatures produced by modern fireplaces and insert units. They serve to improve the efficiency of the system by ensuring that the heat is directed upwards and out of the home, while also protecting the chimney structure from the corrosive byproducts of combustion.

Metal liners also help to enhance draft performance, which is critical for proper operation of a fireplace insert. When replacing or installing an insert, using a metal chimney liner can shield the brick and mortar of an existing fireplace flue from potential damage caused by creosote and other residues that accumulate from combustion processes. It ensures a safer and more efficient venting system, which makes this option a reliable choice for fireplace insert installations.

In contrast, the other options present potential concerns. Using the existing fireplace flue may not provide adequate safety or efficiency, especially if the flue system is outdated or damaged. A BW vent, which is generally meant for non-vented appliances, could pose serious venting issues. Meanwhile, a tile lined fireplace flue may not be sufficiently insulated or may not handle the heat output from a fireplace insert effectively, leading to safety risks such as chimney