Quick answerChimney liner installation in Spokane is most often needed when a high-efficiency furnace upgrade leaves a gas water heater venting alone into a masonry chimney sized for both. A correctly sized metal liner is run down the flue, connected to the water heater and capped at the top, then the draft is tested with the appliance running. Most installs take a few hours.
Updated September 2026
Why an orphaned water heater needs a liner
A masonry chimney that once vented a furnace and a water heater together is far too large for the water heater alone. The small volume of warm exhaust cools in the big, cold flue, the draft weakens, and exhaust can spill back into the basement. The cooled exhaust also condenses on the masonry, and the moisture and acids break down mortar and clay tile over time.
Codes require the venting to be correct for what remains. A metal liner sized for the water heater restores a strong draft and keeps condensation inside a pipe built to handle it. We check this every time we install a high-efficiency furnace in a home with a chimney.
What affects chimney liner cost
What a liner installation includes
Liner work we do
Orphaned water heater venting
When the furnace comes off the chimney, we inspect the flue, measure its size and height, and calculate whether the water heater can vent safely through it as it is. Usually it cannot. We run a liner sized to the water heater's input from the top of the chimney down to the thimble, connect it with a proper vent connector, and fit a cap at the top to keep out rain, snow and birds. Then we run the water heater and test the draft at the draft hood with a smoke pencil or a gauge.
Stainless and aluminum liner options
Aluminum liners suit standard, non-condensing gas water heaters and cost less. Stainless steel liners resist corrosion better, handle a wider range of appliances and last longer, which makes them the better choice where the chimney has already shown signs of condensation or where a future appliance change is likely. Either liner can be insulated in cold, exterior chimneys to keep the exhaust warm enough to draft well. We explain which fits your appliance and chimney before quoting, with both prices side by side.
Aluminum or stainless
| Aluminum liner | Stainless steel liner | |
|---|---|---|
| Suits | Standard gas water heaters | Most gas appliances |
| Corrosion resistance | Moderate | High |
| Lifespan | Shorter | Longer |
| Upfront cost | Lower | Higher |
Chimneys in Spokane's older homes
Many older Spokane homes were built around a masonry chimney serving a gas or oil furnace and a water heater. As those homes upgrade to high-efficiency furnaces that vent through the wall, the water heater is often left alone in a chimney that is now badly oversized, and on an exterior chimney through a long, cold winter that is where condensation damage shows up first. Checking the chimney is part of every furnace upgrade we do.
How a liner install runs
- 1
Inspect the flue
Size, height, condition and obstructions.
- 2
Size the liner
Matched to the water heater's input.
- 3
Quote and permit
Written scope, permit filed.
- 4
Install from the top
Liner fed down to the thimble.
- 5
Connect
Vent connector fitted and sealed.
- 6
Cap
Top plate and rain cap installed.
- 7
Draft test
Water heater run and draft verified.
Chimney liner questions
Why does my water heater need a liner now?
The furnace no longer shares the chimney, so the flue is too large for the water heater alone and it drafts poorly.
What happens if I skip it?
Poor draft can spill exhaust into the house, and condensation can damage the chimney.
How long does a liner install take?
A few hours for most chimneys.
Can you line a chimney with a damaged crown?
The crown or flue may need masonry repair first, which we identify during inspection.
Do I need a liner if I switch to a tankless heater?
No. Tankless units vent through their own pipe, and the chimney can be capped.
Other gas & water heating services we handle
Gas Line Installation
Sized, quoted and permitted.
Gas Line Installation detailsWater Heater Replacement
Sized, quoted and permitted.
Water Heater Replacement in SpokaneGarage Heater Installation
Sized, quoted and permitted.
How we handle garage heater installationMake sure the water heater vents safely.
Call about a chimney liner in Spokane, WA.
