Fire Box Sizes

[Battenkiller]

It sounds like your stove doesn't have a bottom heat shield.

I have a bottom heat shield but it is not in place because I have a concrete floor. I am considering installing the back heat shield (with Kaowool stuffed into the space) and cutting some IFB to fit between the ribs on the bottom to increase internal temps, especially in the back combustion chamber where the secondary combustion is supposed to be taking place. I was meaning to ask you your thoughts on that since I know you have done some interesting trials with insulating fireboxes. Your thoughts?

 

[branchburner]

Besides, it's easy to insulate basement walls, but quite impractical to insulate a slab after it is poured.

Would reflective paint help?

 

[wkpoor]

My bottom heat shield is in place and still the floor gets real hot. If it were on a hearth on the 1st floor I would want to build it per the regs plus knowing what I know from downstairs.

 

[precaud]

Batten, my guess is, insulating the outside of that back combustion chamber will only have effect late in each burn cycle. The chamber has a poured refractory lining inside, yes? Maybe replacing that with lighter IFB would improve it, allow it to come up to temp quicker.

wkpoor, if your stove had side shields, much of the heat that is getting dumped into the floor would be heating air instead and contributing to its circulation though your house.

 

[nate379]

Stove size doesn't really equal wood consumption.

The stove my folks heat their place with is about 15 cu ft. They use about 3 cords a year to heat their ~1100 sq/ft home.

I'm not exactly sure why my Dad made it so big since it's never been loaded even more than 1/4 full. A good hot fire is just 3-4 splits at the very most.

 

[Battenkiller]

Besides, it's easy to insulate basement walls, but quite impractical to insulate a slab after it is poured.

Would reflective paint help?

Who knows? A special low emissivity paint might help if applied directly beneath the stove, but I kinda like that hot floor. I doubt it would last long, especially since it's my workshop. Besides, that would only help with the radiant portion of the heat output, most of which is directed up and outward, not downward. All that heat pooled up between the floor joists isn't being robbed by any heat sink anywhere, it's just getting trapped in a place where I can't easily access it. IMO, once you have the walls insulated and sheetrocked, the main problem with a basement installation isn't in heat loss through the floor, it's getting that abundant heat upstairs into the living space above. The last thing I want is for it to be hotter down there, it gets into the high 80s as it is.

BTW I didn't keep the fire going last night because it had been warm all day and the ladies were baking Xmas cookies until midnight, keeping the upstairs in the low 70s. Last recharge was at dinner time, about 6 PM. I checked the floor below the stove just before I went to bed and it was down to 120º (down from what temp I'm not sure) but still felt great through my wool socks. At noon today (12 hours later) it was still 88º. The floor in the far corners of the basement was only 56º, about the same as it is all day - even in February. The fact that there was still a 32º temperature differential between these extremes some 18 hours after I last filled the stove tells me there was a lot of stored heat available to radiate back into the room, and that stored heat provides extremely stable temperatures throughout the day. Even though outside temps continued to drop throughout the day today, I didn't get cold enough in here to want a fire until dinner time - 24 after I last filled the stove.

Whether or not it makes sense is irrelevant. It's just the way it is.