Time to harness the power of the new collective, I will be installing a new Jotul this winter. I currently have an uninsulated liner running through over 30 feet of external masonry chimney. I've been getting some conflicting advice. On one hand, I'm being told I need to insulate because at this height, and being external, there will be too much smoke cooling in the liner and therefore too much creosote. On the other hand, I'm being told if I insulate, because of the height, I will end up with too strong a draft for my stove to run properly. Any thoughts? I'd love to save money and hassle and not insulate, but I also don't mind paying the money now if insulating will make for safer (less creosote) burning.
Boy that's a tough one. If it was me I would most likely lean towards the insulated liner as 30 foot in an uninsulated masonry chimney is going to cause quite a bit of cooling. If the draft does become a problem there are ways you could try to deal with it vs not being able t deal with a creosote problem. That's just my ten cents though Edit: I have about 24 feet of insulated chimney on my T6 and have never had an issue with it.
If you can use the same liner, i don't imagine you want to cough up the cash for a new one unless it is somehow degraded. That said, I'd try the new stove with the old liner and see how it works. You could always add a pour in insulation at a later time and you don't need to insulate all the way up. You can initially use roxul at the top of the chimney and bottom (assuming you're going without a block off plate) and if you decide to insulate later, use a vermiculite insulation that you can pour in from the top. My two cents..
I have about a 25' interior brick/clay flue tile lined chimney against an exterior wall. It is flex lined and insulated and the draft is excellent. I have a key damper at the outlet behind the stove but have not needed it to slow things down. I have used it on a few occassions on the coldest days, and I can tell that it holds more heat in the stove when in the closed position.
Roxul top and bottom, block of plate too wouldn't hurt. Use it like that for a year then you'll be able to decide whether you need to insulate the whole thing or not. A lot depends how you burn, if you burn 24/7 and keep the chimney warm you likely won't need to insulate, but if you burn irregularly, and allow the chimney to cool down between burns, you may have more problems with draft and creosote deposits. I've used exterior chimneys with just clay flue tiles before (no liner) with no problem.
If I understand correctly you are deciding on insulating the liner you have already and I would say you should. It always better to stay warmer than cooler with a flue imho.
Don't think dampers until you know what the draft is like. Don't worry about scare tactics here. Chimneys too high, chimneys too low; it is not necessarily the case. Like mine for example. Way too short to work. However, the stove does not know that and it works just fine. That same thing can happen with a tall chimney.
What "scare tactics"? People are just offering their opinions based on their experience and their perception of the OP's situation..
"scare tactics" came from the installer. I will wait on the damper. I do burn irregularly, usually from a cold start. Am I hearing strong advice for the insulation?
I know that you had problems with the old stove but how clean did the chimney stay with it? If it was fairly clean I'd wait to insulate.
