Surround costing us heat?

edge-of-the-woods · Oct 19, 2015

So I had the insert out the other day to see how easy it would be to put in a block-off plate. Took a couple pics. Check out the insert with the surround off, compared to the pic of it burning tonight (first burn this year).

Now the surround gets pretty hot to the touch, too hot to keep your hand on for more than a two-count. Here's my question:

Is the surround costing us heat, by keeping hotter air trapped behind it? Is that something the block plate will totally fix, or would I get some more heat out of the insert by putting some holes in the surround in a few places with a 1" spade bit? Is that insane/dangerous?

It just seems like even if a block-off plate was in, there would still be a lot of hot air that's not moving out into the room. Why isn't the surround more of a grate than a solid piece?

Thanks!

KpR · Oct 19, 2015

First, I'd say definitely go with the block off plate. I think you're right about it causing more heat to collect around the stove and behind the surround, but better than collecting up and out of the chimney.

If your stove manufacturer doesn't instruct you to seal the surround to the facade of the fireplace (a few do, I think), my understanding is that surrounds are primarily for cosmetic purposes, and then, yes, some self-made holes would do some good.
On the other hand, that heat collection behind the surround may contribute to maintaining the overall stove temp and allowing the blower to work its magic with hotter air for longer.

Is this an external chimney? Do you think you are losing heat through the chimney structure itself?

Interested to hear what the experts think.

And nice, clean looking setup by the way.

Grisu · Oct 19, 2015

edge-of-the-woods said:
Is the surround costing us heat, by keeping hotter air trapped behind it? Is that something the block plate will totally fix, or would I get some more heat out of the insert by putting some holes in the surround in a few places with a 1" spade bit? Is that insane/dangerous?

It is not dangerous to do. Someone here did a really nice job for their insert: https://www.hearth.com/talk/threads/kuma-sequoia-insert-install.140772/
Nevertheless, your fireplace looks like it is an interior one?! Then a block-off plate with some insulation on top is all that is needed. The heat trapped in the cavity won't magically disappear. It will heat the masonry which will release it slowly into the room(s). You get the effect of a masonry heater for a lot less in price.

You say your surround gets very hot and it looks like it is almost touching the trim. Is that far enough away according to the manual?

jatoxico · Oct 19, 2015

I would guess that a lot of the heat you're feeling is coming off the liner. Your unit sits pretty low so you have a lot of exposed pipe. If you insulate above your block off plate then insulate the exposed liner well I think you would minimize that quite a bit. The insert itself is jacket so that the outermost casing is not as hot as a stand alone stove.

Now you might say "then I'm losing heat that I could use". But I don't think you should heat with the pipe. Keep the flue as warm as possible, With a warm flue you can reduce air and still not make creosote. Heat with the stove not the pipe.

The install is very pretty but I wonder about that wood framing. If you install the plate and insulate the liner I would hope that the surrounds temp would come down so that wood will not get too hot.

edge-of-the-woods · Oct 20, 2015

Thanks all! It's an internal chimney, uninsulated liner, supposedly capped/sealed at the top.

I would have to check the manual on the clearance for the surround, but the dealer that did the install thought it was safe enough.

When the stove cat thermometer is reading 1150, the part of the surround that's nearest the stove reads 125 (with a contact thermometer). It's cool enough to keep a hand on it at the last two inches of the surround, where it gets near the wood.

Once a year our dealer does a cleaning...will the block off plate keep him from getting at stuff he needs to clean, or is he just cleaning the stove and the liner? Nothing will build up in the chimney that I have to worry about, when I block it off?

Grisu · Oct 20, 2015

edge-of-the-woods said:
Once a year our dealer does a cleaning...will the block off plate keep him from getting at stuff he needs to clean, or is he just cleaning the stove and the liner? Nothing will build up in the chimney that I have to worry about, when I block it off?

Since they hopefully cleaned the chimney before lining it only the liner need to be swept. The block-off plate will not be an issue with that.

I took a look at the manual. The top trim should be 14" from the door and the side trim 7.3/8". Looks like you are ok but you can measure it to be sure.

Oregon aloha · Oct 20, 2015

Clearances are to combustibles. You haven't exposed anything that's combustible. The brick around your insert will now absorb and retain heat that use to stay behind the liner. Now that heat will be given back to your home long after the fire goes out. The block off plate acts like the surround by keeping heat from from going up your chimney. It won't charge any cleaning other than behind the insert that is now exposed. I didn't like looking into my firebox so I had a grate with a frame made that fit around my insert and made it look more normal.

jharkin · Oct 20, 2015

jatoxico said:
I would guess that a lot of the heat you're feeling is coming off the liner. Your unit sits pretty low so you have a lot of exposed pipe. If you insulate above your block off plate then insulate the exposed liner well I think you would minimize that quite a bit. The insert itself is jacket so that the outermost casing is not as hot as a stand alone stove.

Now you might say "then I'm losing heat that I could use". But I don't think you should heat with the pipe. Keep the flue as warm as possible, With a warm flue you can reduce air and still not make creosote. Heat with the stove not the pipe.

The install is very pretty but I wonder about that wood framing. If you install the plate and insulate the liner I would hope that the surrounds temp would come down so that wood will not get too hot.

Correct - keep the heat in the flue. You need that heat to power the draft which is why there will probably never be a natural vent wood stove over 90% efficiency (notice that all high eff. boilers and furnaces in the high 90s are power vent for this reason).

Re: the wood. Modern code requires 6 inches of brick reveal to the surround. "Back in the day" they never did this and Ive been in many an old house with the surround within an inch or two of the opening, my own house included. It never gets warm enough even to soften the paint, with a real open fire. I wouldn't be to concerned, though an inspector might.

edge-of-the-woods · Oct 21, 2015

Thanks for the advice!

Maybe this is also crazy...but with all that open space in there behind the surround, would it be helpful to stack in a bunch of bricks in there to close in the space around the insert? So they could soak up the heat, and release it later?

edge-of-the-woods · Oct 21, 2015

If it wasn't for this forum, I would totally have tried something that seemed like a good idea, and somehow killed myself already....

mellow · Oct 21, 2015

Install the block off plate first, that will help the most, then if you want to get creative you could put concrete board on the fireplace walls to insulate it and keep the heat in the fireplace so it will transfer out via the blowers to the room.

Oregon aloha · Oct 22, 2015

edge-of-the-woods said:
Thanks for the advice!

Maybe this is also crazy...but with all that open space in there behind the surround, would it be helpful to stack in a bunch of bricks in there to close in the space around the insert? So they could soak up the heat, and release it later?

If you filled the area with bricks they would absorb the heat but you would reduce the natual convection of the fire box to move the warmed air back to the room. You could take a small fan and blow it back into the firebox to increase air flow. The fan pulling more cool air into the firebox to be warmed as it passes around your stove.

edge-of-the-woods · Oct 22, 2015

Oregon aloha said:
If you filled the area with bricks they would absorb the heat but you would reduce the natual convection of the fire box to move the warmed air back to the room. You could take a small fan and blow it back into the firebox to increase air flow. The fan pulling more cool air into the firebox to be warmed as it passes around your stove.

I like that thought. The surround is back up, though, and I would need to put some holes into it for ventilation, and power for the fan. I'd also need a fan that could handle being in a space that got that hot. Hmmm..

mellow · Oct 22, 2015

edge-of-the-woods said:
I'd also need a fan that could handle being in a space that got that hot. Hmmm..

Wow, just wow, do you not understand you already have blowers on the insert to do that job? If you insulate the area to trap the heat the blowers will dissipate it to the room like it was designed to do. No need to jerry rig it.

Dmitry · Oct 22, 2015

I got the same insert as you are and I live in town next to you. So weather is pretty similar.

Don't drill any holes and don't put blower behind it. The idea is that your insert gonna get hot and your fan will transfer the heat. Just like Mellow said.
In order to work correctly your insert has to burn at high temperature. You need it to achieve secondaries and catalist to work. So no fans behind it.

You might consider to change your faceplate if you want more hot air coming into your room quickly . You got the prettiest but most air restrictive faceplate . It has no vent holes in it and air just goes around it. (not sure if your wife will aloow you

)

I stuck some Roxul behind my insert next to the brick walls in order to achieve hot temps faster. I got internal fireplace so no need to worry about heat loss. Grisu 100% right. It takes longer to bring room up to temp but it stays warm long after fire is gone.

Block off plate is a must

edge-of-the-woods · Oct 22, 2015

Dmitry said:
I got the same insert as you are and I live in town next to you. So weather is pretty similar.

Don't drill any holes and don't put blower behind it. The idea is that your insert gonna get hot and your fan will transfer the heat. Just like Mellow said.
In order to work correctly your insert has to burn at high temperature. You need it to achieve secondaries and catalist to work. So no fans behind it.

You might consider to change your faceplate if you want more hot air coming into your room quickly . You got the prettiest but most air restrictive faceplate . It has no vent holes in it and air just goes around it. (not sure if your wife will aloow you )

I stuck some Roxul behind my insert next to the brick walls in order to achieve hot temps faster. I got internal fireplace so no need to worry about heat loss. Grisu 100% right. It takes longer to bring room up to temp but it stays warm long after fire is gone.

Block off plate is a must

Huh...you mean get a different faceplate for the stove from Regency? Didn't think of that. I wonder which would be best?

I'm ready to build the block-off plate, just waiting for the frigging inspector to come give the install a thumbs-up before I do.

mellow · Oct 22, 2015

I am having a hard time seeing the difference between the low profile and the contemporary surrounds, does the insert stick out more with the contemporary?

Dmitry · Oct 22, 2015

I'm sorry , my bad. I thought you had FPX large hybrid from Travis. The top one looks a lot like yours. Travis has different faceplates.

Screen Shot 2015-10-22 at 2.58.47 PM.png

P.S.: Why do you need inspector for block off plate approval ? It is nor required by code, it's for your own benefit.

edge-of-the-woods · Oct 22, 2015

Ahh dang, I thought there was an easy fix!

I want the stove inspected before the block plate goes in. I don't want to have to take it out, and all the roxul, when the guy shows up.

edge-of-the-woods · Oct 22, 2015

mellow said:
I am having a hard time seeing the difference between the low profile and the contemporary surrounds, does the insert stick out more with the contemporary?

I believe so. Our insert is flush, doesn't stick out a bit. In hindsight, I would rather have gotten one that stuck out a bit, even if it meant expanding the hearth. the stove relies on the blower a lot to get the heat out into the room(s).

mellow · Oct 22, 2015

edge-of-the-woods said:
the stove relies on the blower a lot to get the heat out into the room(s).

Correct, that is one of the trade offs with a flush install. Make sure you are proficient with removing the surround so if you have a power outage you will be able to keep the insert from overheating.

bholler · Oct 22, 2015

mellow said:
Correct, that is one of the trade offs with a flush install. Make sure you are proficient with removing the surround so if you have a power outage you will be able to keep the insert from overheating.

You don't have to pull the surround it will work just fine with no blower it will not put out as much heat no but it will not overheat. I hear this from lots of people about lots of inserts but have never seen anything to support it. And like others have said being an internal chimney you done need anything more than a block off plate. Any heat given up to the fireplace will come back into the room eventually. If it was external then yes insulate behind it but no need to worry about it with yours

mellow · Oct 22, 2015

That is like saying an engine will not overheat with no coolant.

bholler · Oct 22, 2015

mellow said:
That is like saying an engine will not overheat with no coolant.

not exactly an engine needs coolant to keep from overheating. A stove does not require the fan to be running. I have yet to see any warnings about this in any manuals and honestly many inserts can be ordered with out the blower. if it was needed wouldn't these all over heat constantly? Stove manufacturers would be selling battery backups to keep their stoves from melting down ect. I have been doing this a long time and have yet to see a single issue caused by any insert being run without the blower on.

mellow · Oct 22, 2015

Flush mount with a cat running at 1500 degrees, you can do what you want but I would be pulling the surround.

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