Increase Insert Efficency...

KaptJaq · Dec 15, 2011

I have a Vermont Castings Montpelier Insert in my masonry fireplace. Recently I was cleaning and re-sealing the grout on the face of the fireplace and hearth. I had the Meade surround off while I was doing this job. Due to too many distractions I did not finish the job in one afternoon but needed to light the insert since the temperatures were dropping.

While I use the insert without the surround when we loose power to permit as much heat to circulate as possible this was the first time I had the surround off and the fan running. What I noticed was that the tiles and bricks directly above the center of the insert were much cooler than usual. All the heat that is normally trapped behind the surround was escaping into the room.

Looking at the surround I noticed that the side panels were not flush to the fireplace face but only made contact at the top and bottom. The is a gap about a half inch wide and about 18" long on either side. The top panel was flush to the face of the fireplace for its entire length. My thought was that if there was a gap on the top similar to the ones on the side it would let the trapped heat escape instead of heating the masonry fireplace.

I sent an e-mail to VC Customer support asking about this. They stated that the flush top piece was for "aesthetic" reasons only and I could move the insert out a half inch to open a gap to permit natural convection to start. (Tried that but the boss said push it back...)

They also said that there was another way to increase in efficiency. Their recommendation is, and this is a quote from their reply:

" If you want to improve the heat ability when not using the blower, wrap the insert sides and top with a ceramic insulation blanket. Ceramic insulation is white. These blankets can be cut to fit the sides and rear/top and tapes together with metal tape. Your performance with out the blower will skyrocket. "

Has anybody tried something like this? I'm guessing that the heat that usually escapes to heat the masonry mass is trapped by the blankets and kept in the stove.

When I was shopping for inserts I noticed that some recommended only using the insert with the fan running. VC made a point that theirs could be used without the fan. I guess that wrapping with insulation might not be a good idea for every insert, it might add to the chance of overheating the stove. It appears that VC has enough confidence in their product to let you push it to the limit...

KaptJaq

(Edited to correct typo)

bogydave · Dec 15, 2011

Never heard of insulating the stove. (but no experience with inserts)
I agree the stove will get & stay hotter. But more heat out on the front ? (well if it's hotter I'd say yes)
May work good for times you don't need much heat & increase burn times too. Fan on when it gets cold.
Let us know how well it works.

stejus · Dec 15, 2011

I stuffed Roxul insulation up in my smoke shelf and fireplace damper where the stove pipe passes through. I also have a 1/2" to 3/4" gap around the entire surround so it doesn't touch the fireplace face.

When I don't run the blower, the heat pours out of the gap top and sides and the brick face and cast surround gets so hot, you can not touch it. About 2 feet up on the hearth, hot, but not like near the lintle.

With the blower, some heat will pour out, but not nearly as much as without the blower because you are removing the heat from the stove top.

VC's comment about wrapping the stove may make the stove more effiencient retaining heat. However, when you wrap the top and sides of the stove, how to you expect radiant heat to come off the steel if it's wrapped in insulation. Another concern with this is getting the stove too hot if you load it up and not run that blower.

buckdog · Dec 15, 2011

I wrapped my Regency R14 insert, and yes it gets and stays hotter longer. I have posts on here about what I did. I have the entire stove wrapped in 1" thk ceramic wool.
Don't believe any comments by people about stove getting to hot. It will run allot more efficient. I'm glad I did it. I get allot less coaling and more complete burns.

https://www.hearth.com/econtent/index.php/forums/viewthread/48412/

stejus · Dec 15, 2011

buckdog said:
I wrapped my Regency I2400, and yes it gets and stays hotter longer. I have posts on here about what I did. I have the entire stove wrapped in 1" thk ceramic wool.
Don't believe any comments by people about stove getting to hot. It will run allot more efficient. I'm glad I did it. I get allot less coaling and more complete burns.

I don't have mine wrapped and I got the stove top, not the top of the blower chamber, close to 800 the other night. This was done by loading stove full, decreasing air slowly and by the time I was nearly closed, it reached near 800. I turned the blower on because I have never reached this temp and was concerned. I'm not sure I would want it any hotter than that. With insulation on the top of the stove, I would think you would reach this temp and beyond if you don't use the blower.

buckdog · Dec 15, 2011

I've heated my house (3400 sq ft) entirely on wood for 15 years. I think I know what I'm doing. It's a house loaded with lots of windows.

begreen · Dec 16, 2011

buckdog said:
Don't believe any comments by people about stove getting to hot. It will run allot more efficient. I'm glad I did it. I get allot less coaling and more complete burns.

What's good for the goose is not always good for the gander. Every stove is not made alike and some manufacturers have responded that they do not recommend this.

begreen · Dec 16, 2011

buckdog said:
Don't believe any comments by people about stove getting to hot. It will run allot more efficient. I'm glad I did it. I get allot less coaling and more complete burns.

What's good for the goose is not always good for the gander. Every stove is not made alike. Some manufacturers have responded that they are ok with this mod and others do not recommend this.

KaptJaq, contact Vermont Castings and see what they say. If they give their blessings, then you should be good to go.

KaptJaq · Dec 16, 2011

BeGreen said: "KaptJaq, contact Vermont Castings and see what they say. If they give their blessings, then you should be good to go."

BeGreen, In my original post I mentioned that the suggestion came from Vermont Castings. They seem to have customer support on track. I have used the the "Customer Care" form several times and have received timely accurate answers each time. I know when I've asked a good question because instead of getting a quote from or reference to the appropriate documentation I get an e-mail from a gentleman named John Davidson. He appears to know every Vermont Castings product inside out and not just the current product line. It was his suggestion to wrap the insert to increase efficiency when the fan is not in use.

Now I only wish they would sell direct to the public. Sometimes going through the dealer network is frustrating.

KaptJaq

RIJEEP · Dec 16, 2011

Ive been running an insert w/o surrounds for some time. Hot air rises out of the fireplace opening. Works great. In our new fireplace surrounds were not practical as the fireplace has an arch i did not want to cover or make an enormous black metal surround to take away from the brickwork.

Blockoff plate is helpful.

BrotherBart · Dec 16, 2011

KaptJaq said:
I know when I've asked a good question because instead of getting a quote from or reference to the appropriate documentation I get an e-mail from a gentleman named John Davidson. He appears to know every Vermont Castings product inside out and not just the current product line.

John runs the joint. And has for a long time. You bet he knows all of their stoves.

mainiak1 · Dec 16, 2011

Buckdog

I have a 3100i Regency. This is my third year wrapped I ran it unwrapped two years. It is much more efficient wrapped up

Black Jaque Janaviac · Jan 22, 2012

Glad I tripped across this thread! I have a Monte and it struggles to heat the house. I'm asking a lot of it though since I live in Wisconsin, across from a treeless schoolyard, in a 1950s house, two stories, and 500 more square feet than what the Monte is advertised to heat! So it needs all the help it can get.

To help it out I'm installing an NC-30 in the basement heh-heh. But a few bucks worth of mineral wool would certainly be worth the risk.

Lanningjw · Jan 22, 2012

I removed the "soft block off plate" on my BK insert. My cat temps were going up to 2,000 degrees according to the temp behind the cat on a reload. Thought it was better to have the heat go up the chimney and keep the SS liner warmed up on a internal chimney.

I have tried the insert with the surround removed and have not had better results with heating temps in the house. Its all about using the blower with this cat insert....

Retreadsme · Jan 23, 2012

Since my fireplace was large and is on an outside wall, I lined the 3 sides with 1" high density ceramic blanket and also put ceramic blanket on top of the blockoff plate to keep as much heat inside living space as possible when I installed the Regency I3100. I can heat 2000 sq ft by maintaining temps 400-450 measured on the front face above the door on the I3100. Correctly or incorrectly, it makes me believe heat loss is minimal with the ceramic blanket in place.

seeyal8r · Jan 23, 2012

I have the Regency 3100i as well. Our chimney was originally on an outside wall and made of brick. A previous owner, however, built an addition onto the house which made the external brick chimney now on an internal wall. Some bathroom cabinets have been built up against the fireplace. I've felt the brick after several days of continuous burning and it does eventually heat up. It got hot enough in the cabinets that it melted some soft rubber bath toys. Anyway I'll be looking into the ceramic blanket and also sliding my insert out 1/2" to get a little gap behind the surround. Hadn't thought of this before now.

Black Jaque Janaviac · Jan 24, 2012

It got hot enough in the cabinets that it melted some soft rubber bath toys.

:bug:

Is your chimney lined properly? I don't think the stone or block should be getting that warm.

BKInsert · Jan 24, 2012

Lanning said:
I removed the "soft block off plate" on my BK insert. My cat temps were going up to 2,000 degrees according to the temp behind the cat on a reload. Thought it was better to have the heat go up the chimney and keep the SS liner warmed up on a internal chimney.

I have tried the insert with the surround removed and have not had better results with heating temps in the house. Its all about using the blower with this cat insert....

Very interesting! I think that it depends on how far the stove is inside the fireplace, some stoves are flash all the way in, and some extend more out like our BK Insert. It also depends on the way the stove is designed, on the BK Insert the CAT is all the way towards the front, so the hotest part of the stove is inside the room, and with the blower going it capture most of it.

From an aesthetics point of view (could be subjective) I was thinking of getting a flash mounted stove, but I knew that it would "waste" some of the heat by heating the outside chimney wall.

Lanningjw · Jan 25, 2012

BKInsert said:
Lanning said:

I removed the "soft block off plate" on my BK insert. My cat temps were going up to 2,000 degrees according to the temp behind the cat on a reload. Thought it was better to have the heat go up the chimney and keep the SS liner warmed up on a internal chimney.

I have tried the insert with the surround removed and have not had better results with heating temps in the house. Its all about using the blower with this cat insert....

Click to expand...

Very interesting! I think that it depends on how far the stove is inside the fireplace, some stoves are flash all the way in, and some extend more out like our BK Insert. It also depends on the way the stove is designed, on the BK Insert the CAT is all the way towards the front, so the hotest part of the stove is inside the room, and with the blower going it capture most of it.

From an aesthetics point of view (could be subjective) I was thinking of getting a flash mounted stove, but I knew that it would "waste" some of the heat by heating the outside chimney wall.

Are you running a block off plate?

BKInsert · Jan 25, 2012

Lanning said:
BKInsert said:

Lanning said:

I removed the "soft block off plate" on my BK insert. My cat temps were going up to 2,000 degrees according to the temp behind the cat on a reload. Thought it was better to have the heat go up the chimney and keep the SS liner warmed up on a internal chimney.

I have tried the insert with the surround removed and have not had better results with heating temps in the house. Its all about using the blower with this cat insert....

Click to expand...

Very interesting! I think that it depends on how far the stove is inside the fireplace, some stoves are flash all the way in, and some extend more out like our BK Insert. It also depends on the way the stove is designed, on the BK Insert the CAT is all the way towards the front, so the hotest part of the stove is inside the room, and with the blower going it capture most of it.

From an aesthetics point of view (could be subjective) I was thinking of getting a flash mounted stove, but I knew that it would "waste" some of the heat by heating the outside chimney wall.

Click to expand...

Are you running a block off plate?

No, just a bunch of insulation. I was thinking about fabricating a plate maybe for next season. But maybe the insulation is better no?

Huntindog1 · Jan 25, 2012

To run these stoves more effieciently is all about one thing.

Building the heat up in them.

With an insert its most likely a bigger issue as there is more thermal mass sitting behind the stove to heat up.

When starting the stove to get things in the secondary burn mode to be able to shut it all down to burn efficiently, if you can get the heat up higher the thermal mass of the bricks in the stove and behind the stove will store that heat for you. I like to run the stove up hotter not just to barely the point where I think I can get the air shut back down. But I like to get the heat built up quickly so that I dont spend too much time letting the big splits burn all up. If I can get the heat up really hot with some good quality kindling that burns really fast and really hot , my stove temp come up fast plus if I can get the heat up extra hot quickly , what I get is the outer surfaces of the bigger splits out gassing and with the hot coals in the bottom and the fact I got the heat up extra hot the burning of the smoke along with the heated up mass of the stove and fire bricks is enough to sustain a secondary burn just on the outer surfaces of the bigger splits. Its all about building the heat and building it quickly as once the thermal mass is really hot and the burning smoke gases start adding to the heat your stove is now a smoke burner not so much a wood burner as burning smoke lasts alot longer than just burning wood.

Its nice for those guys who have the really big fire boxes as you can leave an open space for a good pile of some hot burning 1" kindling like dry white oak, in my box I have to stack it just right to have an open front row east west load to pile my kindling.

Its kind of hard for people imagine if you load less wood so you can use kindling that you can get just as long burn time with that less of big splits. I read about loading those big 3.5 cu ft NC-30s all the way but I get 8 to 10 hour reloads with alot less wood and plenty of hot coals.

Lanningjw · Jan 25, 2012

BKInsert said:
Lanning said:

BKInsert said:

Lanning said:

I removed the "soft block off plate" on my BK insert. My cat temps were going up to 2,000 degrees according to the temp behind the cat on a reload. Thought it was better to have the heat go up the chimney and keep the SS liner warmed up on a internal chimney.

I have tried the insert with the surround removed and have not had better results with heating temps in the house. Its all about using the blower with this cat insert....

Click to expand...

Very interesting! I think that it depends on how far the stove is inside the fireplace, some stoves are flash all the way in, and some extend more out like our BK Insert. It also depends on the way the stove is designed, on the BK Insert the CAT is all the way towards the front, so the hotest part of the stove is inside the room, and with the blower going it capture most of it.

From an aesthetics point of view (could be subjective) I was thinking of getting a flash mounted stove, but I knew that it would "waste" some of the heat by heating the outside chimney wall.

Click to expand...

Are you running a block off plate?

Click to expand...

No, just a bunch of insulation. I was thinking about fabricating a plate maybe for next season. But maybe the insulation is better no?

Thats all that I have used is a soft (insulation) I dont think ya need it with this insert.....

Increase Insert Efficency...

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