Q&A Wood Stove - Should I get top exit or rear exit one?

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QandA

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Nov 27, 2012
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Question:

I am preparing to build a small log cabin (<1000 sq.ft) with a loft and open great room with relatively low-rising cathedral ceilings. I plan to
build a stone mantle and hearth for a free-standing, non-catalytic woodstove that will be the only source of heat. The approximate dimensions of the hearth are 4.5 ft wide by 4 ft deep. The mantle will stand approximately 5 ft tall with a width of approx. 4.5 ft. I'd like the wood stove flue to exit through the lower center of the mantle and then bend at 90 degrees outside the cabin where it connects to a steel class A chimney (flue and chimney will probably be 6 inch diameter). Should I use a stove with a back-exiting flue or a top-exiting flue (understanding that the top-exit requires an additional 90 degree bend)?

I've read that each 90 degree bend reduces the effective chimney height by 5 feet--with two bends this is a 10 foot reduction. The top of the house is only approx. 20 feet so if the chimney is 22 feet high, will this be sufficient if there are 2 90-degree bends? Does where the flue exits the stove affect either location or performance of the flue damper

(or the stove in general)? At some point in the future, I'd like to replace the class A steel chimney with a stone chimney. Are there any factors I should consider to minimize alterations for this retro-fit? Any suggestions on type of stove, dimensions, capacity, etc. that you can provide would be greatly appreciated.



Answer:

Your stove will exit directly outside and then into a TEE, which is part of the insulated chimney. If the house is only one-story then why not install a straight up-insulated chimney. It will draft much better and cost much less. Assuming this cannot be done, I have the following advice.

1. Yes, choose your stove..different stoves have different draft requirements. Ask the dealer and/or manufacturer about a particular model. As a general rule, a catalytic stove may require more draft and a warmer chimney...this is partially because cats throw less heat up the chimney than non-cats.

2. Stove exit - If your stove does have a rear vent choice, then it might be good to go directly back...but if it does not, don;t worry about it.

3. 22 feet of insulated chimney should be fine, even considering the els.
 
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