I am having a Summit installed on Wednesday. The installer says that a damper block-off plate is not worth it because it is sealed at the top with the full liner. If i remember correctly, i have read in multiple threads that they are beneficial since the smoke chamber of the chimney does not become part of your living room you are heading. Does it also help the performance of the stove? What are your thoughts on whether the plate is needed or not?
Installer says No damper blockoff plate
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I certainly like to put them in. They aren't much effort. At least shove some rock wool up there.
We hear this response a lot. If this is an interior fireplace, then he may be right in that a lot of the heat stored in the masonry will be slowly returned to the house interior. However, if this is an exterior fireplace, you should go for the damper seal blockoff plate to get the best heating capacity from your stove. Without it you are heating up the outdoors. And if this is an exterior flue, the liner should be insulated.
It keeps more of the heat inside your home. There is a whole bunch of masonry chimney between the fireplace & the cap that you lose heat through (especially with an exterior chimney). The stove should perform the same regardless. My installer didn't want to put one in either which helped convince me to do the install myself.
If it is a a Summit insert then there is some benefit. If it is a Summit free standing in the fireplace then there is no way in hell that it shouldn't have a block off plate.
It's an insert and it is an exterior brick chimney that is about 34 ft tall. Thanks for reassuring me that is should have him install the plate.
With a long, tall, exterior stack, I would insist on the block off plate. The last thing you want to try to do is to heat up that mass of masonry in the dead of winter. Nature will win here for sure. With an extra tall flue, I would also downsize the insulated liner to 5.5" based on the experience of hearth.com members with tall flues.
BeGreen said:
+1 on this, insist on the blockoff plate. If not you will be posting next about the poor heat output of your new stove.
I was going to pull my stove to install a block-off plate. However, my chimney is in the middle of the house and it heats up the wall in our upstairs bedroom nicely. So, I don't think I will be doing it.
34' feet wow thats a tall one. I'd definately get a block off plate, thats a lot of masonry to heat.
Some members here have noticed a big increase in stove temps as well - especially surround temps. When my stove is going at 600* I can still put my hand on the surround, others have recorded much higher temps by using a block off plate - to the point putting your hand on the surround would probably leave skin on it! I'll document the temps when I do it.
Some members here have noticed a big increase in stove temps as well - especially surround temps. When my stove is going at 600* I can still put my hand on the surround, others have recorded much higher temps by using a block off plate - to the point putting your hand on the surround would probably leave skin on it! I'll document the temps when I do it.
chris2879 said:
Couple points... If your liner is not insulated at this point, it's better to leave damper as is. This will help keep your liner warm throughout the burn cycle because heat from the stove will rise through the flue. There's nothing worse than a cool liner (poor draft and creosote). If your liner is insulated at this point, an easy quick solution is stuff some unfaced insulation up there as best you can. Getting Rockwool may take some time and unfaced insulation is readily available at big box stores.
The spawling you often see on the face of bricks is usually caused by moisture in the absence of an air and vapour barrier, migrating to the cold side of the brick and freezing. It stands to reason that the bottom should be blocked off to keep humid indoor air out.
stejus said:
Isn't that heat rising from the stove just going to get sucked up by the cold masonry, right along with the heat the liner is putting off?
From what I can tell you need a couple of things:
With that tall of a stack, there is no way I would NOT use an insulated liner.
With an exterior chimney, there is NO WAY I would not have a block off plate installed at the damper.
With that tall of a stack, there is no way I would NOT use an insulated liner.
With an exterior chimney, there is NO WAY I would not have a block off plate installed at the damper.
I do not believe he is going to line the chimney. Lets say that the top plate is sealed and the damper plate installed... now you have no air escaping from the hearth area up the chimney, rather it remains in the room. Since the airspace between the top plate and the blockoff plate is not moving, there should be no exchange of cool air with the exception of the masionary being cool. The heat going up the liner from the stove is not enough to heat that small cavity?
The amount of masonry that you have to heat up to maintain an acceptable stack temp is gonna be HUGE. That heat is going to radiate out of the stone on the open sides faster than you can heat it. You will probably end up with lack-luster draft and a cold, creosote producing pipe on that tall of a run. If you said it was 15 ft tall, you might get away with it. At 35 feet - I wouldn't take that chance on a bet. Just one dudes opinion.
The most heat in the stove pipe is closest to the stove. The further it travels up the stove pipe, the cooler it gets. My liner (25 ft) is insulated and I still get creosote (not much) towards the top 2/3's of the pipe. When outside temps dip below freezing, there's not much you can do to prevent cooling an un-insulated liner.
I ran my stove the first season un-insulated because I installed in Dec. My draft improved considerably and my creosote dropped since insulating. I recommend you discuss this with your installer. If he’s any good, he’ll know the benefit of an insulated liner.
I ran my stove the first season un-insulated because I installed in Dec. My draft improved considerably and my creosote dropped since insulating. I recommend you discuss this with your installer. If he’s any good, he’ll know the benefit of an insulated liner.
I would be concerned about getting cold air back down the flue myself. My fireplace was like an ice cold air fall with the damper open, and I used the old damper plate as the bottom seal, only with a 6 inch hole cut through it for the flex to pass through. Worked like a champ, plus I stuffed insulation in there too.
BeGreen said:
I have an interior chimney, full insulated liner, and jacketed insert (without face plate so I can reach on in there.) It's not terribly hot up there when I wave my hand up above the back of my insert, but it is warm and of course heat rises sooo... But also, got two snows last week, not too deep but enough to stick, and it definitely melted around the chimney first, so I figure I better get on it. Since someone gave me some Kaowool I may just put it up there in the damper minus the plate for a start.
Point being I suspect that a blockoff plate is needed even on an interior one to maximize the performance of an insert.
tickbitty said:
This definitely keeps the snow from melting around the chimney on my house and the other ones I have helped with, all have insulated block off plates. My house has an exterior chimney and the others are interior chimneys. I would imagine that the kaowool stuffed in there would be an immediate improvement and you can add the plate later. The ones we have done all have rockwool above the block off plate and under the top cap and that works well also
When I was shopping for a stove hardly any dealers included a block off plate on the install, some said it wasn't necessary due to the liner being sealed at the top, some said they would pack the damper with insulation. I think it's just something that adds to their time and they can't really charge alot for it, so they try to avoid it.
I would insist on the block off plate, and I wouldn't let them get away with just packing insulation up there. Insulation is designed to insulate, not block air flow, and in this application you want to block air flow. Insulation is better than nothing, but why not have them do it the right way from the start.
As a side note, does anyone else feel like most of the people working at stove shops no very little about heating with wood and very little about the products they sell. When i shopping for my insert I visited at least 10 different shops and I only ran across one salesman who I felt was on the ball. Most couldn't even talk about a stove in their shop without looking at the brochure. Most of the stoves I was recommended for my house wouldn't heat my closet. Very annoying and scary. Sorry for rambling!
I would insist on the block off plate, and I wouldn't let them get away with just packing insulation up there. Insulation is designed to insulate, not block air flow, and in this application you want to block air flow. Insulation is better than nothing, but why not have them do it the right way from the start.
As a side note, does anyone else feel like most of the people working at stove shops no very little about heating with wood and very little about the products they sell. When i shopping for my insert I visited at least 10 different shops and I only ran across one salesman who I felt was on the ball. Most couldn't even talk about a stove in their shop without looking at the brochure. Most of the stoves I was recommended for my house wouldn't heat my closet. Very annoying and scary. Sorry for rambling!
I also felt that way, when I asked about cat or non/cat my local dealer salespeople said stuff like "it depends on whether you want it or not" or something vague like that. They didn't do a real good job of explaining the advantages or differences or reasons for price issues on different models either and for the brands/models they didn't have on the floor the best they really did was manufacturer's brochure. I ended up buying from someone out of town but the dealer I bought from had it easy anyway, I did all the research here on hearth.com so I knew exactly what I wanted. Talked to the local dealer again and others about installation and none of them recommend an insulated liner or block off plate and act like you are crazy to consider such an outlandish thing. (especially on an interior chimney.)krex1010 said:
The local wood stove dealer also thought I was crazy when I asked for a T6 price. Said he wouldn't sell it to me because he "knew" I'd be coming back dissatisfied. It's just an opinion. Fortunately for us, Tom Oyen had better common sense and advice.
These folks are not living in your homes, not chopping your wood, paying your bills. If you want your insert to produce good heat, then give it the advantage and block off the damper area. If it's a hearth heater sitting in the fireplace, block it off low, right at the lintel level if possible.
These folks are not living in your homes, not chopping your wood, paying your bills. If you want your insert to produce good heat, then give it the advantage and block off the damper area. If it's a hearth heater sitting in the fireplace, block it off low, right at the lintel level if possible.
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