Firebox insulating ???

[mitroll2]

I would like to insulated all the sides of my firebox except the top. I will be adding a warmer chamber on top. Do I need to enlarge the firebox to account for the added 3/4 to 1' thickness of the walls. I'm worried about the loss of cubic inches of firebox space. Maybe the insulation will account for this in less lost heat. Another thought was to insulate the top also and just have a vent on top for smoke and heat. What are your thoughts on this. I live in Michigan so heat loss can be an issue. Thanks for the inputs.

 

[woodyg]

Good morning Mitroll2. When I built my FB, I used the number I came up with for the inside volume of the FB. Then the insulation was added to the outside and a metal skin over the top of that. If I understand your question correctly, yes that should be your inside volume. Hope this helps

 

[mitroll2]

Yes, thank you. That was basically what I was asking.