Recommendations for basement stove/insert based on multiflue chimney

[Efarg]

Located is eastern PA bucks county. I am looking to install a stove or insert into my existing masonry fireplace in my basement for additional heating. The current flue is 12x12 terracotta and about 35-40ft. Its in good condition but will need to add a preinsulated stainless liner (6 or 8inch depending on models).

Looking for max heat output for extended/full time burns to help heat our house about 4500sf. Have considered Jotul 500 V3 for stove and Kuma Cascade LE for insert.

We have a double barrel 2 - 12x12 about 28ft terracotta flues for our first floor masonry fireplace that we would like to keep intact for open burning (i know stupid for heating and have high vaulted ceiling in living rm)

Question is whether to go woodstove or insert? I think the stove will require more of a hearth in front of the existing bricks to get proper clearance whereas the insert will just pop in without hearth mod. Also do you see any drafting issues seeing that i have 3- 12x12 flues and a 6inch round terracotta flue (water heater) all within the same chimney area? Terra cotta flue to be used for the new stove/insert is the one next to the 6inch round. Chimney was recently rebuilt and is constructed of cmu with new stucco, brick, masonry infill, copper cricket/flashings, and custom chimney cap

Will i have issues with the 35-40ft run on the new flue liner? I would like to keep the manufacturer matched sizing although i have seen some people drop down to 5.5inch if too much draft

Appreciate the help and feedback as I have never owned a wood stove or insert!

 

[begreen]

Will i have issues with the 35-40ft run on the new flue liner? I would like to keep the manufacturer matched sizing although i have seen some people drop down to 5.5inch if too much draft

Yes, there is a good chance that draft will be exceptionally strong and could make the stove hard to control. It has me wondering about a 5" liner to help. How well does the basement fireplace draft?

 

[stoveliker]

I would do a stove. Easier to add a key damper.

Also, you may have to make one flue longer so they don't end at the same heit, to avoid sucking the smoke from the stove into the flue of the fireplace and stinking up the fireplace room

 

[Efarg]

Yes, there is a good chance that draft will be exceptionally strong and could make the stove hard to control. It has me wondering about a 5" liner to help. How well does the basement fireplace draft?

Thanks i was wondering if undersizing was a code or insurance issue or up to manufacturer? Im planning to do a test burn in the basement to check draft and then open the damper on 1st floor double barrel to see if any drafting issue and then start a fire on 1st floor to see how it goes if any backdraft. Quick smoke test showed good pull on the basement flue. Anything else that I can check as a preliminary or while having both fires going?

 

[Efarg]

I would do a stove. Easier to add a key damper.

Also, you may have to make one flue longer so they don't end at the same heit, to avoid sucking the smoke from the stove into the flue of the fireplace and stinking up the fireplace room

I was wondering about the multiflues downdrafting into each other and also with the hot water heater flue next to them. Is there a code or general rule for the height differences and proximity? Currently they are offset in height from every other flue but not sure whata best

 

[stoveliker]

I don't think there is code, but people suggest having 1 ft different termination height.

The stove sucks in air thru its inlet, so the home will have to let in make-up air somehow (it won't become a vacuum...)
The easiest way is through that big hole, the other chimney. Even when the fireplace damper there is closed, because they generally are quite leaky.
So if the other flue sucks in air, and the stove exhaust is waiting there, you'll get that back inside.

 

[Efarg]

I don't think there is code, but people suggest having 1 ft different termination height.

The stove sucks in air thru its inlet, so the home will have to let in make-up air somehow (it won't become a vacuum...)
The easiest way is through that big hole, the other chimney. Even when the fireplace damper there is closed, because they generally are quite leaky.
So if the other flue sucks in air, and the stove exhaust is waiting there, you'll get that back inside.

Thanks these are the questions im trying to get to the bottom of. The house is pretty drafty for makeup air but i will report back after i do the test run using the current fireplaces one at a time, damper open/closed, and both fires same time so at least ill have some real life indicator. Not sure if the 6inch liner or stove exhaust would change the air flow compared to regular masonry fireplaces as is. Hoping to work out the kinks beforehand here

 

[begreen]

Back siphoning of smoke into the lower floor's flue is a common enough problem that there are products marketed to address it.

Chimney flue stretchers

Elevate your chimney's performance with our Chimney Flue Stretchers. Enhance safety and efficiency while reducing downdrafts. Choose from durable stainless steel or copper options today!

www.fireplace-chimneystore.com

The founder of Hearth.com had a side business making these extenders.

 

[Efarg]

Back siphoning of smoke into the lower floor's flue is a common enough problem that there are products marketed to address it.

Chimney flue stretchers

Elevate your chimney's performance with our Chimney Flue Stretchers. Enhance safety and efficiency while reducing downdrafts. Choose from durable stainless steel or copper options today!

www.fireplace-chimneystore.com

The founder of Hearth.com had a side business making these extenders.

Thanks good to know. When we run the new liner can try to make that the tallest one since will be operating most frequently