Reflective properties

[Easy Livin’ 3000]

I am working to minimize the heat sink effect of a massive stone chimney and fireplace. I was able to fit a full bat thickness of roxul behind my insert to isolate the back of the fireplace from the heat. I have a temporary block-off plate and the final one in the works for the flue. Now for the sides. I would like to add something to the inside sides between the insert and the stove to continue to minimize the heat sink effect. There is not enough space to fit roxul on the sides, so I'm thinking sheet metal to reflect the heat back into the room.

Two questions: First, if I paint the sheet metal on both sides, will I be negating the advantages of the shiny sheet metal reflecting the heat back? As I don't have a surround, having the shiny sheet metal visible on the sides might not be real popular around here but I am willing to try it out and see how it looks.

Second, is there something that I can paint the back of the sheets with that will add a tiny bit of insulation to keep the heat on the inside, away from the chimney and minimize conducting the heat?

I had one of those emergency blankets that was reflective silver on one side and orange on the other when I was a kid. I think I remember reading that the technology was developed for the space program. If I can keep some more of the heat in the living space using this idea, seems like an easy addition.

 

[TradEddie]

Does your insert have an air/convection jacket? If so, you probably aren't losing as much heat as you imagine to the back and sides. Another alternative is if you can insulate on the other side of the stone. That way, instead of being a heat sink, that stone can become a store of heat that will slowly return to the room. That's what I did and it works extremely well.

TE.

 

[Easy Livin’ 3000]

Does your insert have an air/convection jacket? If so, you probably aren't losing as much heat as you imagine to the back and sides. Another alternative is if you can insulate on the other side of the stone. That way, instead of being a heat sink, that stone can become a store of heat that will slowly return to the room. That's what I did and it works extremely well.

TE.

Yes, the insert has a jacket, so you are probably right about not loosing that much on the sides and back. I'm not sure how I might insulate on the other side of the stone as you mentioned, but I'm real interested to hear how you did it, if you are so inclined?

 

[TradEddie]

You know, I misspoke a little. My fireplace is a "heatilator" type setup, so I filled that old convection cavity with roxul, additionally I am able to access the rear of that brick/block from my garage, and once I was confident that the brick never got "hot", I used a combination of roxul and xps to insulate. My hearth wall is one course of red-brick, so I insulated behind that too, and that's where I get a good masony heater effect from the sides of the insert. Sometimes, that brick will be 70F when I wake up in the morning.

TE

 

[Easy Livin’ 3000]

You know, I misspoke a little. My fireplace is a "heatilator" type setup, so I filled that old convection cavity with roxul, additionally I am able to access the rear of that brick/block from my garage, and once I was confident that the brick never got "hot", I used a combination of roxul and xps to insulate. My hearth wall is one course of red-brick, so I insulated behind that too, and that's where I get a good masony heater effect from the sides of the insert. Sometimes, that brick will be 70F when I wake up in the morning.

TE

That makes sense. My old fieldstone fireplace has brick walls and back that were added much later, along with an iron damper. At some point I am going to tear down the plaster around the brick, and I may be able to get between the brick and the original stone. If I can, I will probably insulate in that gap, like you describe.