masonry vs steel pipe chimney

[dlussier]

I'm about to install a Vermont Castics Encore wood stove in my basement. The chimney will be ~30' tall. I'm undecided on whether to have a masonry chimney with 8x8" liner or a stainless steel one. The masonry will match another one on the house and look good and is around the same price ($3K) of the metal one. However, some literature indicates the steel one's work better since they are insulated vs a heat sink situation with the masonry variant.

Any suggestions on which is better and why? If I don't lose much performance with the masonry, and they are the same price, I'd rather go that way. My concern is that with 30' of chimney, I'll want optimal performance which I can only get with metal?

DaveL

 

[bluefrier]

The masonry will match another one on the house and look good

DaveL

You could install a masonry chimney and line the inside with a stainless steel liner instead of a traditional clay liner. This would be pleasing to the eye and still give the perfomance of a metal chimney.

 

[dlussier]

I guess I could do that, but it sounds like it will be $6K instead of $3K since I'll be paying for both masonry and metal chimneys Too much $$$???

 

[fraxinus]

If the entire chimney is within the house (except, of course for the portion above the roof line), I don't think there would be a significant difference in draft between metal and masonry. The greater mass of the masonry will retain warmth and is essentially its own insulation. 3k is an exceptionally reasonable price for a masonry chimney and if it were me, I'd go with that option. After all, masonry has been the primary constuction technique for chimneys for a millenium or so. The masonry option would also, I think add more value to your house than stainless steel.

 

[yukiginger]

I had no idea a masonry chimney of that height could be had so affordably. Another thing to consider is that with a metal chimney exposed inside your living area you may get some additional heating benefit from the pipe.

MarkG

 

[Loki]

I am confused and any explanation would be appreciated.
It seems that the higher the efficiency of the furnace/stove, the more insistence by the dealer/manufacturer that a SS liner be used. I have heard that it's because of the higher burn temps of the efficient units. That doesn't make sense to me since they also tout their low exhaust temps... due to their high efficiency.

No doubt there are times when a liner makes sense due to the age/conditon of an existing chimney. But why the hard push to use a SS liner ?

I have an interior masonry chimney ~ 25' tall that is almost 25 years old. What advantage is there to reducing the cross section ?

 

[dlussier]

Thanks for the replies guys. I guess I should have also noted that the entire chimney will be outside. From the basement installation of the stove, the pipe will go through the wall to outside within 4' of the stove and run outside on the side of the house (backyard on North side) to the rooftop which is around 24' tall (then an extra 6' or more for slope clearance req's for a total of ~30'). If I had confidence we won't have back puffs and back drafts, I would go the masonry route since they are around the same price. My caution is the literature on the wood stove itself indicates performance is better with metal:

"Masonry is a traditional material for chimneys, but it can perform poorly when it serves an ‘airtight’ stove. Masonry is a very effective ‘heat sink’ - it absorbs a lot of heat. It can cool the smoke enough to diminish draft. The bigger the chimney, the longer it takes to warm up. It’s often very difficult to warm up an outdoor masonry chimney, especially an oversized one, and keep it warm enough to maintain an adequate draft.

Metal Chimney
Most factory-made metal chimneys have a layer of insulation around the inner flue. This insulation keeps the smoke warm. The insulation is less dense than masonry, so a steel chimney warms up more quickly than a masonry chimney. Metal doesn’t have the good looks of masonry, but it often performs much better."

 

[Risser09]

It’s often very difficult to warm up an outdoor masonry chimney, especially an oversized one, and keep it warm enough to maintain an adequate draft.

I believe they are intending to say that the diameter of the chimney itself is going to have an effect on the performance of the stove, rather than the height of the chimney. This is why most linings/chimneys/stovepipes are 6" in diameter...better performance.

 

[bluefrier]

I guess I could do that, but it sounds like it will be $6K instead of $3K since I'll be paying for both masonry and metal chimneys Too much $$$???

No, I don't think the price would double. Ask your chimney specialist if it is possible to subsitute the clay liner (the inner part of the chimney) for a stainless steel liner.