Home Forums Hunting & Shooting Hunter's Campfire Building a walk-in cooler?

Here is a link to a discount on a Coolbot, which allows you to use an air conditioner to bring the cooler down to, and maintain, 36-38 degrees. I put one in this year and it works great! Very simple to install.

http://storeitcold.referralrock.com/l/80568C08/

I just happen to have such a cooler in my summer DIY plans. Can you give us some details as to size, thickness of insulation, etc? I'm always happy to see what others have done and how it works.

I'm planning a 6x8' cooler. I haven't planned the details yet but I'll probably use 4" of foam board. It'll be open on top under a metal roof with a good air space, screened off to keep the starlings out.

Mine is a 6x8 also. Since it was built in a new pole barn, the two outside walls are 8 1/2" of layered pink Foamular 150, with a 1/2" Polyiso board with the aluminum facing on the outside walls, facing outward working as a vpor barrier. For the walls inside the building, I used 2x6's with the polyiso on the outside and the foamular 150 on the inside. For the inside, I couldn't decide on a liner and just put 1/2 foamular over everything to close it up tight for the first year. Those walls ended up being 6 1/2" thick, with the Polyiso and the inner 1/2 " liner. The ceiling was built like the walls.

Under the floor is 2" of Foamular 250 with a vapor barrier beneath that.

Every layer of insulation was cut to fit and I caulked the seams of every layer. For the door, I ended up buying a good exterior house door with a foam filled frame. I was going to glue another inch of foamular to the inside of the door but never did. The door is the weak link in the insulation, but it hasn't been an issue.

My research said "do not use fiberglas insulation". The foamular was not cheap, but the cooler works very well. The coolbot took it from 75 to 37 degrees in a short time, like 10 minutes.

When hanging meat, be sure to keep the fan on to keep the air circulating. Some air conditioners allow the fan to cycle on and off in an energy saver mode. Don't do that with meat.

I'm not sure what you mean by "open on top with a good air space". I actually built my ceiling about 18" under the building ceiling so that i could store things on top of it. I think you'll want your ceiling insulated with foamular also.

Go to the Coolbot site, they have plenty of info on construction and also answer questions over the phone. I found them very helpful.

Buy lots of caulk!

By open on top, I meant that there will be a good air space above the insulation. I used to be a roofer and more than once, a search for 'roof leaks' turned out to be insulation tight against the roof with no air space. Moisture would get through the insulation and freeze to the underside of the roof deck. When the sun hit it, it would melt and run down through the insulation and ruin a ceiling. The fix was to somehow get a good air space in there with ventilation to get the moist air out.

Coolbot's website recommends R-40 on all 6 sides. 2" Foamular is R-10 per inch so 2 2" layers should be R-40. Also, leaving a well caulked air space between layers can add another 5 or so R's.

A steel door with a foam core will have an R-value of 5 or less. High efficiency doors are a little hard to find without paying a wad for one. Most will give you a U-factor but that's related to the glass which you don't want in a cooler. Most don't list an R-value. A 2" layer of Foamular glued to the door will increase the R's by about 5x.

About that discount...you can also get a Coolbot from Amazon but you'll pay $50 more for it.

Anyone have any plans in a PDF file.

You dont need plans or dwg. I sketched mine out on mthrfking hardees bag. Actually all you really need is a brain and a tape measure.

Mine is 8x8 with a 9ft ceiling. With a winch in the ceiling. Plans....pffft!!!

I can get mine down to 36f in about 1/2 hour.

18k btu LG with electronic frost sensor. My walls are 6" thick. Ceiling too and my floor has 3" styrofoam down under 3/4" plywood.

Sounds cool

I've considered building one on a utility trailer so I can move it when it's not in use.

I've been wanting to build one as well. Been considering building a permanent one in the garage or making some modular panels that can easily be erected in a small shop out back.

Planning on a 16x12 shop with a loft. It'd be easy to insulate the floor and loft and then have a couple 6' panels that can be zipped up. Stack them up when not in use.

It'd save some space in the garage and make it easy to put in a drain etc....

I believe the 2" foamular is R-10 in total, not per inch. Be sure to verify.

You're right. I was thinking crooked. Coolbot recommends an R value of 25, not 40 so 2 layers of 2" still get you close to their suggestions.

Just finished painting the inside of a 13'x20'x8.5' just a few minutes ago. AC unit and coolbot showed up yesterday. Thanks for posting.

Rock Chuck,

You also mentioned the doors having about an R-5 You are right, most of them do. I searched around a bit and ended up with a Plyco if I remember right. Their model 31 with insulated frame has an R-11 rating. It was over $500 though, but way cheaper than a cooler door...

the lowest priced door I've seen is a plain steel exterior door with a couple layers of foam board glued & screwed on. I've seen them at Home Depot for under $150, prehung.

I have built-in a number of reefer/freezers on yachts. Present thinking is, for the money, Dow blue board insulation is preferred because it does not absorb moisture (which kills insulation performance). Leave no air gaps at joints in insulation. Insulate all surfaces adequately, including doors. And pay special attention to minimize air gaps between doors and door frames. Use D-gaskets at these interfaces to minimise heat gain.

Perhaps more important than even the vapor barrier is an infrared barrier. Aluminized Mylar can do both; shiny side out.

I looked at the Dow board at Lowes. It has the same R-value/inch as the pink OC but costs twice as much. Lowes only has it here in 2x8' pieces, not 4x8, so it has many more gaps to seal. It's tongue and groove, which the OC isn't but good caulking will take care of that.
Anything I end up building will have siding over it so light reflection shouldn't be a problem.

Unless it's metal siding, use an IR barrier.

Neighbor triple insulated wall and ceiling of about a 12 x 12 foot space with a yard sale air conditioner through the wall. Gets it down into the mid 30's.

I almost hate to bring this up - building permits. I realize that most of these coolers are built without one but they're still required and there's always the possibility of it coming back to bite you don't have one. One easy way to avoid that is to make it portable, like build it on a trailer. You don't even need tires, just a frame and an axle to make it look portable.