To insulate or not to insulate

[Brucewayne10000]

Hello,

Been lurking here for a while and really appreciate the advice and opinions shared. I'm going to be installing a Blaze king princess insert soon.

What I'm seeking is opinions on insulating the liner. I have a 35ft masonry chimney with a very strong draft. What is the consensus on insulation? What are the main benefits to spending the extra $300 on the insulation kit?

All opinions are greatly appreciated.

A secondary question, can the bk proncess cord be plugged in inside the fire box?
Thanks much

 

[bholler]

well do you have the required clearance from the outside of the masonry to any combustible material? if not you need to insulate to meet code. but other than that the performance will be much better insulated

 

[begreen]

With 35 ft of pipe the flue gases are going to have a lot of time/distance to cool off. The Princess already has cool flue gases. The risk of creosote buildup increases greatly with an uninsulated chimney when the flue gas temp falls below 250F.

Have you discussed this extra tall flue with your dealer? Will they be measuring draft to be sure the flue doesn't exceed BK's draft spec for this stove?

 

[Brucewayne10000]

Thanks for the replies. I do have the required clearance to combustible materials.

Two of the dealers I've spoke to, including the one I'm going with said they only insulate on about 20 % of the time, and that's mainly due to cracks in chimney or other faults.

This took me by surprise since insulation seems to always be recommended here. I live just south of cleveland, oh so maybe they do less here because of climate?

 

[Sakuji]

Hey Bruce.

Congrats on that new stove you bought. I also just ordered one couple of days ago to be the first of two possible installs.

I hope you don't mind if I also put in my 2 cents here. The two Master's above (Begreena and Bholler) nailed the points about the insulation.
Having a liner insulation or putting in a pre-insulated liner is pretty much the standard (this is what I'll be installing). Every decent pro and good diy installer I talked to or read about, insulation is practically the very first thing they mentioned. For a couple of cents extra cost for additional security over the lifetime of the liner is basically a good deal.

I think a more important point that Begreen already mentioned is the tallness of your chimney. But without knowing your actual chimney set-up my speculations about it are just that- speculations. If it is a standard run-off-the-mill single flue, single appliance set-up then here's BK recommendation: 15 foot working draft path from stove collar to flue tip to attain that 0.05" water draft. Too small has its own problems but irrelevant to your case. Too tall also has it's problems (too strong draft etc) and related effects (over-firing etc). So that's not good also. There are a couple of threads here discussing the problems. The good thing is there are a number of solutions for it. Either way, as far as I've seen as being advised, the best guide is what Begreen mentioned: draft meter. I've seen one being used before when we had our furnace vent upgraded. It's just 30 bucks added to the service fee they billed us. A good (and documented) peace of mind that the whole job was done within spec. I believe that is the best way to approach it before thinking of solutions for a posible overdraft situation. Anyway, I have not found the max draft the princess insert can handle on the literature I've seen. Perhaps you can call BK directly or consult BKVP.

At any rate, I wish us both good luck for our installs. I've owned a BK freestanding before and she was awesome that's why i'm sticking with it for this first install on a different house. However, these beauties do really cost a bunch of monies when brand new. I think that's more of a good reason to use insulation.

EDIT:
I didn't see your new post prior posting mine.

 

[mellow]

Here is that word again... climate... is that being spread around the dealer network as a good excuse not to insulate?

Insulation has nothing to do with climate, it has everything to do with keeping the pipe warm to help draft while keeping creosote levels down due to a cold pipe and maintaining the clearance to combustibles for UL listing, something insurance companies like to see in the event of a house fire.

Your install is on the really tall side and the problem with an insert install is you can't install a pipe damper to regulate the draft (can't get to it in the fireplace). I am not sure how much the thermostatic control on the BK's can overcome an overdraft situation, they would be able to tell you more. I would go straight to BK, not the dealer on this issue.

 

[bholler]

Thanks for the replies. I do have the required clearance to combustible materials.

Is your chimney interior or exterior? Interior chimneys need 2" of space between the outside of the masonry to any combustible material the entire length of the chimney and an exterior chimney needs 1" Most chimneys do not have this are you sure yours does?

Two of the dealers I've spoke to, including the one I'm going with said they only insulate on about 20 % of the time, and that's mainly due to cracks in chimney or other faults.

Just because they don't do it doesn't mean it is not required. Many stove shops will use the cheapest liner they can find and do the install as cheaply as possible in order to sell more stoves. Not all do this but most i have come across do. And cracks have absolutely no bearing on insulation requirements it is all about clearance and performance. If the chimney is cracked that is a totally different problem that needs addressed seperatly