Burlington VTChimney & Stove RepairRequest Service
Menu
ChimneyFireplacesStovesRepairsAppliancesProblemsService AreaAll servicesGuidesResourcesRequest service
Sizing and specifying

Are Chimney Liners Worth It? What You Are Buying

Whether chimney liners are worth it depends entirely on which of three situations you are in, and lumping them together is why the question feels unanswerable. Situation one: the existing flue has failed, cracked tiles, missing mortar between sections, damage after a chimney fire, and a liner is not an upgrade but the repair. Situation two: you are connecting a modern appliance to a flue built for something else, which is almost always a masonry chimney many times larger than the appliance needs, and the liner is what makes the installation work at all instead of merely work better. Situation three: everything is sound and correctly sized. A liner is optional, a choice about longevity and not a necessity. Most people asking are in situation one or two without knowing it, so the only honest answer starts with an inspection, not a guessed price.

Request serviceAll resources

Three situations, three different answers

The question 'are liners worth it' has no single answer because it covers three unrelated cases. This is how to tell which one you are in.

SituationHow you would knowIs a liner optional?
Existing flue has failedCamera scan shows cracked or displaced tile, missing mortar, fire damageNo: it is the repair
Modern appliance on an old flueAppliance outlet is far smaller than the flue it vents intoNo: it is what makes the install work
Unlined chimney, modern applianceNo liner present at all; common in pre-war housingNo
Fuel conversionOil or solid fuel flue now serving gasEffectively no: condensate will attack the masonry
Sound tile, correctly sized flueScan shows intact tile and joints; sizes matchYes: genuinely optional
Cold exterior chimney, chronic weak draftDraft complaints that persist after blockage is ruled outOptional, and commonly transformative

What a liner does

Three things. It contains combustion products so they cannot reach the masonry or the framing around it. It protects the masonry from acidic and corrosive by-products, which matters enormously with gas and oil appliances. And it provides a passage sized correctly for the appliance, which is what allows the appliance to draft as designed. The third is the one people underestimate, and it is frequently the one that turns a disappointing stove into a good one.

What it does not fix

A liner will not cure a draft problem caused by house pressure, by a blocked cap, by a chimney too short for its roof, or by a fireplace opening out of proportion with its flue. It will not repair a failing crown, spalling brick or bad flashing, and installing one into a chimney with those problems means doing the masonry later with the liner in place. Anyone proposing a liner without having established the cause of your actual complaint is selling instead of diagnosing.

Where insulation changes the answer

On an exterior chimney in this climate, a cold stack on an outside wall, which describes a great many Vermont houses, an insulated liner does considerably more than a bare one. It keeps flue gases warm enough to establish and hold draft, which improves how the appliance runs, and warmer gases deposit less, which reduces creosote. Also sometimes what allows the required clearance to combustibles to be met where the chimney passes through framing.

How to tell whether you are in situation three

You would need a camera scan showing sound tile with intact joints for the full flue length, and an appliance whose outlet matches the flue size. Both of those are findings, not assumptions. Both come from a Level 2 inspection. If nobody has scanned your flue, you do not yet know which situation you are in, and that, instead of a price, is the useful next step.

Two chimneys side by side serving the same stove. In the correctly sized flue the exhaust stays warm, moves quickly and leaves the top. In the oversized flue the same exhaust expands, slows and cools, condensing on the flue wall as creosote.Correctly sizedWarm, fast, leaves the topOversizedExpands, slows, cools, condensessameapplianceboth sidescreosote
Draft depends on flue gases staying warm. A flue larger than the appliance needs lets them cool and condense.
Sizing and specifying

Where this leads

Chimney Liners

Stainless liner installation, relining of deteriorated clay tile flues, and correct sizing when a new wood, pellet, gas or oil appliance goes into an old chimney.

Read about chimney liners →

Chimney Inspection

Level 1, Level 2 and Level 3 inspections for annual maintenance, property transfers, insurance requests, fuel changes and after a chimney fire or a suspected malfunction.

Read about chimney inspection →

Wood Stove Service

Annual wood stove servicing, gasket and glass work, baffle and firebrick replacement, and installation or replacement of freestanding stoves and inserts.

Read about wood stove service →
Are Chimney Liners Worth It? What You Are Buying

Common questions about are Chimney Liners Worth It? What You Are Buying

Are chimney liners worth the money?+

In three of the six common situations they are not optional at all. They are the repair or the thing that makes an installation work. In one they are optional. Which you are in is a finding from a camera scan, not a judgement call.

My chimney has no liner at all. Is that illegal?+

An unlined chimney built before liners were required is broadly not made illegal by a later code. A different question from whether it is safe to connect a modern appliance to it, and once you alter the system current requirements apply.

Is a liner the answer to a chimney that will not draw?+

It fixes one caused by an oversized, leaking or cold flue, which covers a large share of them. It does not fix one caused by house pressure, a blocked cap, a short chimney or a fireplace out of proportion with its flue. Diagnose first.

Should the liner be insulated?+

On an exterior chimney in this climate, almost always. It keeps gases warm enough to draft correctly, reduces creosote for the same reason, and can be what meets the clearance requirement where the chimney passes through framing.

What kind of life should I expect from a stainless liner?+

It depends on the alloy relative to the fuel, how the appliance is run, and whether it is kept clean. Correctly specified it is a long-term component; specified in the wrong alloy for the fuel it fails from the inside, invisibly.

Can I line a chimney myself?+

Sold as a DIY product and the parts that go wrong are the parts a homeowner cannot easily judge: correct diameter for the appliance, correct alloy for the fuel, adequate insulation, clearance through framing and a proper termination. Getting any of those wrong is expensive.

What if the old clay tile is in the way?+

It gets broken out to make room for the correct diameter. Legitimate work and it belongs in the scope explicitly: a quote silent on the existing tile may be planning to fit an undersized liner around it instead.

Do I need one for a gas appliance?+

Frequently, because masonry flues built for a fireplace or an oil burner are far too large for a gas appliance. Exhaust cools and condenses against the tile, and that acidic condensate attacks the masonry from within over years.

How much upheaval does a reline involve?+

Less than people expect. Most of the work happens at the top of the chimney and at the appliance connection, and on a straightforward chimney it is commonly a matter of a day or so instead of a building project.

Why do two liner quotes differ so much?+

Almost always scope. Material and alloy grade, diameter, whether it is insulated, how it terminates, and what happens to the existing tile. With those five stated the quotes are comparable, and without them they are two numbers attached to unknown work.

Could two appliances share a single liner?+

As a general matter appliances need their own flue, and connecting two into one is a serious finding, not an economy. Where anybody proposes it, get the reasoning in writing.

What is the first thing I should do?+

Get the flue scanned. Every version of this question resolves into a finding about tile condition and flue size, and both come from a camera. A price quoted before that has been established is a price for unknown work.

Read next
Who To Call For a Chimney Leak: Roofer, Mason or Chimney Company?→