DIY walk in cooler build

[coldbr3w]

I'm building a walk in cooler for my mushroom farm here in southeastern Pennsylvania. I'm converting a shed, using a Coolbot + AC unit, and lining the inside with those TVP plastic panels. Goal temp is 36∘F (outside is mostly ≈75∘F).

What insulation is the MVP here? Foam board? Spray foam? What thickness do I need to hold that low temp? Any tips from people who have built one?

 

[guvnur.jake]

Closed cell foam is usually best for sealing and high R value in tight spaces and if you go with foam board, use at least 3 to 5 inches, tape and seal every seam and plus, remember good vapor barrier on the warm side is key to keep moisture out. Hope this helps in any way

 

[slvr22_bd]

I'm building a walk in cooler for my mushroom farm here in southeastern Pennsylvania. I'm converting a shed, using a Coolbot + AC unit, and lining the inside with those TVP plastic panels. Goal temp is 36∘F (outside is mostly ≈75∘F).

What insulation is the MVP here? Foam board? Spray foam? What thickness do I need to hold that low temp? Any tips from people who have built one?

That sounds like a great project! For your insulation MVP, rigid foam board is the way to go! I recommend polyiso for its high R-value or XPS for moisture resistance. To hit your 36F goal against 75F outside, aim for a minimum of R-25 everywhere. So that's about 4 inches of polyiso or 5 inches of XPS. If budget allows, professional closed-cell spray foam is actually the best option as it air-seals perfectly. Most importantly in humid PA, the vapor barrier is critical. It must be on the warm, exterior side of the insulation. Meticulously seal all seams with tape and sealant if you're using foam boards. Also don't forget to insulate the floor and focus on a quality, sealed cooler door!

 

[Alan]

@coldbr3w for a tight 36°F, polyiso or XPS foam boards around 4–5 inches work, but closed-cell spray foam is ideal if budget allows. Don’t skimp on the vapor barrier and sealing seams ... especially with PA humidity, it’ll make or break your cooler.