What size chimney liner does a wood-burning insert need?

Sized to the appliance, not the old flue

The instinct is to match the liner to your big masonry chimney, but a wood insert wants the opposite. You size the stainless liner to the insert's flue collar — most commonly 6 inches in diameter, occasionally 8 on a larger unit — and run it full-length, from the insert straight up to the top of the chimney. The insert's manual states the required diameter, and that's the number that governs. A full liner is not optional on a modern EPA insert — an unlined or partially lined chimney won't draft it safely.

Why a right-sized, insulated liner matters

Oversizing a liner is a real mistake, not a safe hedge. A flue that's too big for the appliance lets exhaust cool and slow down, which weakens draft and lets creosote build faster — the last thing you want on a wood-burner. A properly sized, insulated stainless liner keeps the flue gases hot and moving, which means stronger draft, cleaner burns, and less creosote to sweep.

That's doubly true in our mountains. WNC's ridgelines, tall trees, and cold night air make draft harder to establish, and a warm, correctly sized liner is what overcomes the downdrafts and cold-flue 'plug' that plague tall chimneys here.

What we handle

We inspect and measure the existing chimney, size the liner to your specific insert, and install insulated stainless top to bottom with the proper cap and connection — then pull the permit and meet the inspector. A wood insert is only as good as the liner behind it, so we don't cut that corner. It's the difference between an insert that drafts clean and one that smokes back into the room.

Thinking about a wood insert for an open, drafty fireplace? Call (828) 545-0525 or visit our Asheville showroom.