Wood stove insert installation advice; Do I need to insulate liner? Is a reducer a bad idea?

[a316co2000]

Hi everyone,

I'm hoping someone can help clear up some conflicting information I've been finding in regard to whether or not I need to insulate a stainless steel chimney liner during installation of a wood stove fireplace insert, and if using a reducer/adapter to save on chimney liner expense is a bad idea or not.

I live in Springfield, VA (think DC area) and just purchased a 2-story home built in 1972. The house has a normal fireplace (no insert of any sort) with a 13x13 chimney. From my research, I believe it is an EXTERIOR chimney (it is located on an outside wall; if I go outside, I can see the brick chimney run the entire height of the house).

I recently came across an old Derco Grizzly insert (pictures of same stove from another thread attached), which I was able to pick up for free (and by free I mean it took 4 of us 2 hours to remove it from the fireplace it was in and hoist it into my truck). The insert has a blower which I believe can be thermostatically controlled, as well as a catalyst combustor. The outlet is on top and is round, 8 inches in diameter. It was in pretty nice shape, but my wife doesn't like the "80s/90s" look of it, so I've sanded it and re-painted with a semi-gloss black high temperature paint. It's actually turned out really nice looking thus far (still need to put it back together).

Now for my questions, of which I have two: 1) Do I need to insulate the stainless steel liner? 2) Is using an 8" to 6" reducer to save money on a liner a bad idea?

1) Unfortunately, the previous owners just had it shoved in their fireplace with no liner, so now I need to purchase one. I've been doing a lot of searching online and in local fireplace supply stores, and I'm finding conflicting information as to whether or not I really NEED to insulate the liner. Some websites (typically the ones trying to sell me something) say insulating is an absolute must; others say it's recommended; some say it's not necessary. I went to a local store and the guy working there said when they do liner installs they don't insulate because we live in VA where we don't have sub-zero winters, and that if we were in Wisconsin, etc. it would be another story. I don't know if this guy is a moron, or if he actually knows what he's talking about.

I'm in the military, so I know I'm only going to be in this house for 4 years (3 more winters after this one), so any savings on utilities from having a liner installed is only a concern for the time I'll be living there. After that I would like to rent the house out, so my chimney maintenance expenses could continue indefinitely if I do so. Not sure how that plays into decision-making on whether or not to insulate.

What I do know is that the cost to insulate an 8-inch, 25 foot liner is very high. I've located a non-insulated liner kit on craigslist, still new in box, for $400, and I believe I can talk the guy lower. However, insulating the liner will cost me another $300-$350 (that's the cheapest I'm able to find it online). I've seen some pre-insulated kits, but they're all 6" liners.

Do I really need to insulate my liner? Is the benefit worth the cost considering how long I'll live in the house?

2) I could save hundreds of dollars on a liner kit if I buy an 8" to 6" reducer like the one at this link: http://www.firesidechimneysupply.co...rce=googleps&gclid=CNGFj6ekxLwCFeJj7Aoda14Agw. I've been advised (by people trying to sell me stuff) that using a reducer will cause draft problems and make the stove less efficient, but if that's the case, why do they even make them?

Is using a reducer really a bad idea, or is the chimney supply guy just trying to sell me a more expensive liner, and more expensive insulation?

Here is a thread that relates to my exact stove make/model. I've found it useful and it may answer other questions specific to my stove: https://www.hearth.com/talk/threads/need-advice-on-derco-grizzly-stove.80317/.

I really appreciate any help/advice anyone can offer.

 

[Jags]

In a perfect world...Insulated 8" liner. Throw in an insulated blockoff plate above the stove.

 

[a316co2000]

In a perfect world...Insulated 8" liner. Throw in an insulated blockoff plate above the stove.

Let's say my world isn't perfect...financially speaking, and I'm trying to save a little cash while still being safe...

 

[Jags]

If your chimney is solid - then a simple liner will be a safe install. Reducing the size of the pipe is untested for that stove. Will it be safe - probably. Will it work correctly - no idea. Are you willing to take the chance that the 6" won't draft properly? What happens if it doesn't and you have to pull it and STILL go with the 8".

My personal opinion is that other than cost - there is no downside to insulating a liner. For a one time fee of a couple hundred bucks I would try to figure out how to make that happen.

And don't forget the blockoff plate.

 

[begreen]

Seems like it is drafting ok if you are currently dumping into a 13 x13" chimney with no issues. You might be ok with 6" insulated, but it is not advised. If you do put in 6" insulated it will be an experiment. Any liner you put in will be safer than the current setup.

PS: I updated your poll.

 

[mstoelton]

+1 on the blockoff plate. Instructions on how to make it are found on this site.

 

[RickBlaine]

How to make a metal block-off plate: https://www.hearth.com/econtent/index.php/articles/making_a_block_off_plate/

...and thank you for your service! My brother is USAF (a pilot) and he and the wife have a house in Old Town, Alexandria. They have two fireplaces that they don't use because of the inefficiencies. If my conversion goes well, then this summer we will convert those two. Good luck!

(BTW, that was a very well-written post)

 

[a316co2000]

First, thanks everyone for all the advice and for replying so quickly.

I do have a few follow-up questions:

1) Jags, when you ask if my chimney is "solid," are you asking if it's in good shape? I had it inspected a month ago when the wood stove insert was just a pipe dream, and the guys said there were some exterior cracks that would need repair ($300), but other than that they said it was in great shape...didn't even need to be cleaned.

2) Jags, what does the blockoff plate do?

3) begreen, I haven't used the stove yet, so I don't know how it would draft. It's currently sitting in my garage with the paint drying, and I wasn't planning on installing it until I got the liner kit. Thanks for updating my poll.

4) mstoelton, did you forget the link for how to make that blockoff plate? EDIT: Nevermind, someone posted one. Thanks RickBlaine, and good luck to you (and your brother) too.

 

[Jags]

Yes, by "solid" I mean in proper working order.
A blockoff plate will keep the heat from going up the open chimney. It will improve your heating performance.

 

[KindredSpiritzz]

I understand budget limitations all to well. If it was me i'd just do the uninsulated 8 inch liner and maybe have to clean the chimney more if you get creosote buildup.

 

[a316co2000]

I understand budget limitations all to well. If it was me i'd just do the uninsulated 8 inch liner and maybe have to clean the chimney more if you get creosote buildup.

If I do, is an annual cleaning recommended? Again I live in VA so the stove would typically be used primarily from late November to mid-March, at most.

 

[Jags]

If I do, is an annual cleaning recommended?

At a very minimum it needs to be inspected/swept once a year. For newbys, I HIGHLY recommend a more frequent inspection/sweep until you know how things are going.

ETA - Get on the wood processing now. You are already running short on time to get dry fuel for next season.

 

[a316co2000]

At a very minimum it needs to be inspected/swept once a year. For newbys, I HIGHLY recommend a more frequent inspection/sweep until you know how things are going.

ETA - Get on the wood processing now. You are already running short on time to get dry fuel for next season.

Thanks, will do. Would insulating reduce the frequency of inspections?

I've already started working on wood. Fortunately for me there are lots of "free firewood" posts on the local craigslist, and I have access to a log splitter.

 

[Jags]

Thanks, will do. Would insulating reduce the frequency of inspections?

It can. An uninsulated flue will typically run cooler wall temps. They loose heat to the surrounding brick/stone/clay liner. Insulating helps retain the heat in the liner which in turn keeps the temps in a safe operating range and can improve the draft. All good things in respect to creosote production.

 

[KindredSpiritzz]

insulating might reduce the frequency of cleanings, i'd still do it at least annually. Mine burns dirty so i clean once a month thru the season, your need may vary from mine.

 

[BrotherBart]

$400 for the liner kit is great. I live South of Manassas and have a 21' un-insulated liner in my outside brick chimney. Since it is a double flue chimney it should be about as bad a heat sink as you can find but the liner works great. It has a block off plate at the bottom with Roxul insulation on top of the plate and a little Roxul packed under the chimney liner top plate.

I have been burning since late October and went up to take a look this morning before the snow storm hits. Not gonna need to brush it till the end of the season. But you need to figure on at least an annual chimney cleaning. You change the oil in the car. You get the central heating unit serviced. Clean the chimney.

People talk about how outside chimneys are so inefficient but I slipped my infrared thermometer in my pocket before I hit the ladder today. I had to go check it with the stove burning due to time constraints. The stove was burning at a steady 540 degrees stove top and the very top of the liner was at 328 degrees. It was 18 last night and 22 while I was up there. Bad boy ain't loosing squat to those bricks around it.

Get that eight inch liner and install it, load and go. But you are gonna need good dry, seasoned ain't a word, wood, examine that cat and find out the proper way to operate that cat stove.

Welcome to hearth.com neighbor.

 

[oconnor]

I feel the pain of the four year house, bought four in my time flying for the Queen here in Canada. Usually get it just the way I like it, then it's time to sell.

If you can, insulated it to keep it warmer and reduce creosote. If you can't, then install it with a full liner and block of plate. Bart is right, if you burn it right with dry wood your setup should be fine. Enjoy.

 

[bholler]

The insulation doesn't cost that much and it will improve performance and safety of your system. Also almost all liner manufacturers require it and will void the warranty if you don't insulate. As far as using 6" it might work but if it doesn't you will have wasted the time and money on that 6".

 

[a316co2000]

$400 for the liner kit is great. I live South of Manassas and have a 21' un-insulated liner in my outside brick chimney. Since it is a double flue chimney it should be about as bad a heat sink as you can find but the liner works great. It has a block off plate at the bottom with Roxul insulation on top of the plate and a little Roxul packed under the chimney liner top plate.

I have been burning since late October and went up to take a look this morning before the snow storm hits. Not gonna need to brush it till the end of the season. But you need to figure on at least an annual chimney cleaning. You change the oil in the car. You get the central heating unit serviced. Clean the chimney.

People talk about how outside chimneys are so inefficient but I slipped my infrared thermometer in my pocket before I hit the ladder today. I had to go check it with the stove burning due to time constraints. The stove was burning at a steady 540 degrees stove top and the very top of the liner was at 328 degrees. It was 18 last night and 22 while I was up there. Bad boy ain't loosing squat to those bricks around it.

Get that eight inch liner and install it, load and go. But you are gonna need good dry, seasoned ain't a word, wood, examine that cat and find out the proper way to operate that cat stove.

Welcome to hearth.com neighbor.

Thanks neighbor. I called the guy about the $400 craigslist liner kit. His has a "tee connection" which would be useless to me, but it doesn't have the appliance/stove connector that I would need to connect it to the top of my stove insert. He said he would take $350 for it, but I'd likely have to spend $50 on the missing appliance/stove connector, so I'm still looking at $400.

I found this liner kit on ebay: http://www.ebay.com/itm/8-x25-316TI...394?pt=LH_DefaultDomain_0&hash=item3cc86182a2. $435 plus free shipping for the complete kit sounds like a better deal than $400 total with the hassle of driving to the guy on craigslist and back, plus buying the appliance/stove connector separately, so I think I'll be ordering from ebay.

I called the seller on ebay with some clarification questions and he was pretty much a used car salesman, which was annoying. Aside from trying to tell me their prices were more than what ebay listed, he did have some useful info. He said that if I wasn't going to insulate the entire liner I should put "insulation plugs" at the bottom and top of the liner, which I'm assuming is the same as what you did with the Roxul insulation on top of the block off plate and under the chimney liner top plate. Is applying this insulation in those two places as simple as it sounds? He tried to sell me two of these to get the job done: http://www.chimneylinerdepot.com/store/903/product/No-Foil-High-Temp-Insulation-Section-24x48.html; but I'm pretty sure the Roxul is a more cost effective alternative. Is this the stuff I would need to get?http://www.lowes.com/pd_138683-1278...t=roxul&pl=1&currentURL=?Ntt=roxul&facetInfo=

Thanks for all the advice everyone. I'm really learning as I go here.

 

[bholler]

One big factor for weather or not to insulate is can you confirm that you have proper clearances to combustibles on the entire chimney? if not you should insulate because by insulating you get a zero clearance to combustibles on the exterior of the chimney

 

[BrotherBart]

Springhill on eBay is Chimney Liner Depot. Good bunch to do business with. I have myself.

 

[BrotherBart]

Yeah that is how I did it and what I did it with.

 

[BrotherBart]

One big factor for weather or not to insulate is can you confirm that you have proper clearances to combustibles on the entire chimney? if not you should insulate because by insulating you get a zero clearance to combustibles on the exterior of the chimney

13 X 13 tiles and an eight inch liner gives you the clearance to combusibles before you even get to the the tiles. Much less the bricks or the framing members.

 

[bholler]

Were did you get that info bart? Clearance to combustibles on a bare pipe is 18" minus 1/3 for the masonry is 12" right. you will have an 8" pipe centered in a 11" flue that is 1.5" not 12". Ok I saw he said 13 by 13 even if that was the inside size that would still only be 2.5"

 

[bholler]

http://www.rockfordchimneysupply.co...nd-Maintenance-Instructions-for-Rock-Flex.pdf
http://www.nationalchimneysupply.com/wp-content/uploads/2012/05/CB-installation-instructions.pdf
http://lib.store.yahoo.net/lib/elitedeals/ventinoxduraflexproandswinstructionmanual.pdf
here are a few sets of installation instruction I found all say that to meet ul-1777 specs for zero clearance to combustibles in a masonry chimney insulation is required.