Solar Kiln Building. Why insulate the floor?

[Nick Sorenson]

I'm in the middle of building a kiln and I read in a few sets of plans that say to insulate the floor. While it seems like more insulation sounds like a good idea, why insulate the floor? It's hard for me to think that it'd prevent much heat loss since heat rises and obviously the floor is the lowest point in the structure. Is it necessary to insulate the floor?

[Dan Hintz]

Heat may rise, but you're providing a large heatsink to the kiln if you don't insulate it.

[JohnT Fitzgerald]

Nick - hot air rises, not heat by itself. So yes, the hottest air will be at the top in your kiln; but hopefully the air near the floor will be pretty darn hot too (especially compared to the ground). You want to prevent that heat from escaping by conduction or radiation through the floor.

[Nick Sorenson]

That makes sense. I have always heard the attic in a house is the most important insulation. But yep heat conduction definitely has an effect. I guess I had better insulate the floor!

[Chip Lindley]

Besides maximizing heat near the kiln floor, insulation and a vapor barrier will help keep ground moisture from wicking up, prolonging the drying cycle. A cold floor in a humid chamber could cause mold or mildew issues. under the lumber.