# Shop Heat Question



## PHPaul (Sep 5, 2021)

I'm building the stand/plenum for a downdraft hot air mobile home furnace to sit on.  Frame is angle iron, 24x18, 18" high cube.  Sides will be covered with bolt-on sheet metal panels.  Bottom will sit on an uninsulated concrete slab.  

My question is, should I insulate between the bottom of the frame and the slab?  I can see the slab being a giant heat sink and sucking up a lot of the heat for no good purpose.

I'm thinking a piece of 2" blue board, some half inch spacers and a sheet metal floor in the frame.

Yes?  No?  Won't make any difference?


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## woodchucker (Sep 5, 2021)

yes.. like you said it will be a heat sink.  if it didn't have the rest of the floor it would retain the heat. But being attached it is a heat sink.


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## GL (Sep 5, 2021)

First, congratulations on having heat - cold shops suck, changing temps condense water, heat makes everything happier.  
Foam on bottom instead of concrete is better.  If you already have sheet metal sides, you might consider making a sheet metal bottom, raised up a few inches, and forgo the foam.  Air is a good insulator also.  The bottom might extend past the base to kick the air flow up as it exits into the shop. Couple of legs and the flex of the metal could make it sort of adjustable, if that became important. If you really want some OCD, round the back and bottom to make the air flow around the back corner better.


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