On this page
Of all the lines on a stove installation quote, the liner is the one people try hardest to remove, and the one that most often decides whether the installation works. It is worth understanding what it is actually for.
Three jobs a liner does
It sizes the flue to the appliance. Every stove has a specified flue diameter, and the flue should be close to it. A big old masonry flue built to carry the smoke of an open fire moves far more air than a modern stove produces, which means the gases slow down and cool.
It keeps the gases hot. Hot gases rise, which is what draught is. Cool gases stall, smoke back into the room and condense on the walls of the flue as creosote. An insulated liner in a cold exterior chimney can be the difference between a stove that works and one that sulks.
It contains the combustion products. Old masonry chimneys crack, lose mortar and sometimes were never properly lined. A continuous stainless liner gives a sealed path from the appliance to the open air, which is a fire and carbon monoxide matter, not a nicety.
What you are buying
- Material and grade. Stainless steel in a grade suited to wood-burning. Cheaper grades exist for other fuels and are not interchangeable.
- Rigid or flexible. Flexible liners negotiate offsets in old chimneys; rigid runs suit straight flues and have slightly better flow.
- Diameter. Matched to the appliance’s outlet, not to the chimney’s size.
- Insulation. A wrap or a poured insulation around the liner. On an exterior chimney, in a cold climate, this is where the improvement in draught comes from.
- Termination and cap. A cap that keeps rain and animals out, and an appropriate top plate sealing the flue.
- Warranty and conditions. Many liner warranties depend on annual sweeping and on burning appropriate fuel. Read what would void it.
How to read the quote
Ask for each of these in writing, because “reline the chimney” is not a specification:
- Liner diameter and the appliance it is sized for.
- Material, grade and thickness.
- Whether it is insulated, and how.
- Whether the existing clay liner or any obstruction has to be removed to fit it.
- What happens to the crown, flashing and cap.
- Warranty terms and the maintenance they require.
- Permit and inspection, and who arranges them.
If a quote is much cheaper than the others, find out which of those seven items it leaves out. The usual omissions are insulation, the cap and crown work, and removing an old clay liner that stops a properly sized stainless liner from fitting. None of those are optional extras; they are the job.
When you may not need one
- A new installation with a listed metal chimney designed for the appliance from the start. The chimney is the liner.
- An existing flue that is already the right size, sound and warm, for example an interior masonry chimney with an intact liner close to the stove’s outlet diameter. This is uncommon but real, and an inspection will tell you.
- A pellet stove venting horizontally through a wall with manufacturer-approved pellet vent pipe, which is a different system.
The way to find out is an inspection before the stove is bought, not a guess afterwards. A sweep or installer with a camera can tell you in an hour what the chimney is, what condition it is in and what the stove would need.
Symptoms of a flue that is wrong for the appliance
- Smoke into the room when the door is opened, particularly at the start of a burn.
- Slow, reluctant lighting and a fire that needs the door cracked to get going.
- Rapid creosote build-up, requiring sweeping more than once a season.
- A stove that will not hold a fire overnight even loaded and damped.
- Cold air pouring down the flue when there is no fire, which usually means a cold, oversized chimney.
None of those are cured by a better stove. They are cured by the chimney.
Related reading: Pay for a Chimney Inspection With a Defined Scope and Clearances, Hearth Pads and the Inspection.
Questions people ask
Does a wood stove need a chimney liner?
Usually, when it is being connected to an existing masonry chimney. The flue has to be sized to the stove's outlet and kept hot enough for the gases to rise; old fireplace flues are typically far too large, which causes poor draught and heavy creosote.
Is an insulated chimney liner worth the extra?
On an exterior chimney or in a cold climate, yes. Insulation keeps flue gases hot, which improves draught and reduces the condensation that becomes creosote. It is often the difference between a stove that draws well and one that smokes.
How long does a stainless chimney liner last?
It depends on the grade of steel, the fuel and the maintenance, and manufacturers publish warranties that generally assume annual sweeping and appropriate fuel. Ask for the warranty terms in writing, including what would void them.
Can I install a liner myself?
It is sold as a DIY product, and it is also a permitted, inspected part of a heating installation in most jurisdictions, with real consequences if the sizing, insulation or termination is wrong. At minimum, have the finished work inspected.
Where these figures come from
- Choosing the Right Wood-Burning Stove US Environmental Protection Agency, Burn Wise · epa.gov
- Heating Fire Safety US Fire Administration, FEMA · usfa.fema.gov
- Best Wood-Burning Practices US Environmental Protection Agency, Burn Wise · epa.gov
Figures last checked September 2026.
