Q. What size stove pipe should I install in my wood stove?
A. To get that answer, all you need to do is look at your wood stove and measure the inside diameter of the flue collar on the wood stove itself. If the stove has a 6” flue collar, then you should use 6” stove pipe and 6” chimney pipe through the roof. If your stove has a 8” flue collar then you run 8” stove pipe all the way up.
We offer 5", 6", 7", 8" and 10" sizes of stove pipe. Once you determine the size you need you then can decide on what brand is best for your installation. To learn more about what brand to choose read our article How to Choose your Brand of Stove Pipe.
Q. I’m replacing a wood stove that had 8” stove pipe and 8” chimney pipe but my new stove requires 6” pipe. Can I just run the 6” stove pipe to the 8” chimney?
A. Technically that answer is no. You should run 6” pipe all the way through the roof but some of you aren’t going to do that and if you decide not to do that, then you need an increaser. If you decide to run stove pipe that is a different diameter from your chimney pipe, there are several things to consider. The performance of your wood stove could be compromised by decreasing the efficiency from running two different sizes in pipe. Drafting your stove properly will also be an issue, you can read more about these in the next answer section below.
Q. Where can I install the increaser?
A. If you have a 6” flue collar and you need to attach it to an 8” chimney, you want to install that 6” to 8” increaser as close to the chimney pipe as possible. So you come off of the stove, if you’re going up to a support box or over to the wall for a wall thimble, you want to put that increase as close to the wall thimble or as close to the support box as possible. That way you get as long of a run using the appropriate size pipe as possible. Now be warned, if you do that, you may get some drafting issues. As you open the door, you may get some smoke coming back into the room. You may find it hard to start a fire, because you may find it difficult to get that draft going in the first place. You can also damage the efficiency on the wood stove itself, the stove might not perform as efficiently as it’s supposed to, when you don’t have the right size pipe installed the entire way up.
Whether you are looking to install a new wood stove or replace existing stove pipe with a old stove, consider longevity as your deciding factor for replacing pipe or the stove. If you have 8" stove pipe and chimney pipe already installed and want a new stove, spending the extra money to get the stove with the correct flue collar will prevent drafting issues and your stove will perform how it is suppose to. Ultimately, you want a wood stove that is performing at it's highest ability and will heat your home the most efficiently.
Also, if you are installing a new wood stove, measure the clearances to combustibles as this will determine whether you need single-wall or double-wall pipe. Typically, single wall black stove pipe is the most common for a install. Most single wall pipe is black steel and has welded seams. There is also Snap-Lock pipe available which is a cheaper option that may require cutting and crimping for your install.
If you are looking to upgrade or replace your current stove pipe, you might be more interested in double-wall pipe as it is more durable and can significantly help improve the draft. However, single-wall pipe is still a great option because it does allow heat to radiate back into your home from the pipe and you can install a heat reclaimers, which allows you to retain the maximum amount of heat going back into your home. Heat reclaimers cannot be installed with double-wall pipe.
There are many checks and balances to consider when determining what size of pipe to use in your install, the best option will always be to match the flue collar of your stove and run that same diameter stove pipe and chimney pipe all the way up through the roof.