Which chimney liner should be higher?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Chadillacgrill

New Member
Oct 15, 2019
14
Ogilvie, MN
I have two fireplaces. One upstairs and one downstairs. I have wood stove inserts in each of these. I just put the one in the basement in and am going to use that one as my main. Which chimney liner should be higher and how much higher should it be to prevent back draft from getting sucked into one or the other if both stoves are running? Thanks!
 
The main floor flue should terminate 12-18" above the basement flue.
 
Begreen is absolutly right. But you can almost always have them at the same height with no problems. I would try that first then extend with class a if need be.
 
Begreen is absolutly right. But you can almost always have them at the same height with no problems. I would try that first then extend with class a if need be.

Interesting. I've never heard of the problem. I guess I should be happy I don't have it.

Being curious; Does this apply to all wood burning devices? Before I installed the wood boiler in the basement I had 2 different wood stoves and never had a hint of trouble.
 
Interesting. I've never heard of the problem. I guess I should be happy I don't have it.

Being curious; Does this apply to all wood burning devices? Before I installed the wood boiler in the basement I had 2 different wood stoves and never had a hint of trouble.
When they are equal height there is a risk of smoke getting pulled down the basement flue when the upstairs insert is burning and the basement insert is not. Negative pressure in the basement is not uncommon. If there is a hint of negative pressure issues in the basement, then the upstairs flue will need to terminate higher than the basement flue. This problem happens enough that there are products on the market to address the issue.
 
Last edited:
When they are equal height there is a risk of smoke getting pulled down the basement flue when the upstairs insert is burning and the basement insert is not. Negative pressure in the basement is not uncommon. If there is a hint of negative pressure issues in the basement, then the upstairs flue will need to terminate higher than the basement flue. This problem happens enough that there are products on the market to address the issue.
Does it apply to just inserts or are wood stoves also effected?

Like I said I was not effected a I'm thankful for that. Having a 18" SS addition on my chimney would bother the hell out of me every time I drove in. I woudn't even let the plumber run the vent pipe out the roof on the front of the house.
 
Do you guys put rain caps on your liners or does that interfere with draft?
Yes, definitely. A proper raincap will not interfere with draft.
Does it apply to just inserts or are wood stoves also effected?
It applies to open fireplaces even more, but yes to stoves or inserts if the basement has negative pressure.
 
One more question off subject here. The stove I bought downstairs is a double door stove similar to a Fisher wood stove. It doesn’t have glass doors. How do I know if the fire is burning the way I want it? Not sure how to know if it’s shouldering or over firing. Any advice would be cool. Going to give her to maiden light tonight. Hahah. And I should be able to burn both stoves at the same time correct? Thanks again.
 
One more question off subject here. The stove I bought downstairs is a double door stove similar to a Fisher wood stove. It doesn’t have glass doors. How do I know if the fire is burning the way I want it? Not sure how to know if it’s shouldering or over firing. Any advice would be cool. Going to give her to maiden light tonight. Hahah. And I should be able to burn both stoves at the same time correct? Thanks again.
A pipe thermometer will tell you everything you need to know
 
This has happened to me, I have open fireplaces in basement and main floor, when burning in the main floor fireplace a few times I would go in the basement and you could smell a strong smoke odor, but no smoke.
Chimneys flues are right next to each other at the top.
Didn't happen every time but good to know now since I'm installing a liner in the main floor fireplace for my new stove !! Thanks...
 
  • Like
Reactions: begreen