Fermentation chamber insulation question...

I'm nearing completion of my fermentation chamber build. I copied the many threads here on HBT on building out a chamber off of a dorm fridge. I built a box with framing and 1/2" plywood off of the fridge. I used that 1/2" pink insulation from Home Depot, R value is 3.0. I was originally going to put 2 layers of the insulation but after lining the whole chamber once it took awhile and was kind of a pain to get good seems so I'm considering sticking with 1 layer of insulation. The other option I'm considering is getting a little thicker insulation, maybe the 1.5" stuff, and insulating the exterior of the chamber, outside the plywood. I haven't seen anyone try this here on HBT insulating the exterior of the fridge in addition to the interior, so I'm wondering if anyone has any ideas on if insulating the exterior also will add significant insulating character similar to double insulating the interior.

Any ideas?

thanks

 

Insulating the outside will help just the same as insulating the inside, it will just be uglier .

I also am building my own fermentation chamber, out of 2x4 frame and covered with 1/8" plywood. I am doing 2" of foam board insulation on all 4 sides, and the top and bottom both have 3.5" of foam board insulation (overkill, I know). I did the top and bottom that way because that's how deep the 2x4's were, and I had accidentally bought more foam board than I needed.

Personally, I wouldn't go with less than 1" of foam board plus the 1/2" plywood. As you can see, I'm doing even more than that. The thing with these are, the better you insulate, the less strain you will put on the dorm fridge. Obviously you'll hit a point of diminishing returns, and don't want to compromise too much on how much space you have in the fermenter. But I would probably add at least another layer of 1/2" insulation if I were you. Also make sure to tape or caulk the seams afterward so that you don't have any air leaks.

Put some pictures up!

 

+1
I used 2" foam board on mine. I definitely think any less than 1" and your dorm fridge would have a hard time keeping it cool on a warm day. If you can go more than 1", I'd try that route.

 

+2....the more the better. I think I used 5 inches of polystyrene insulation in the walls, floor, and lid of my lager chamber. I went with 4 inches in my ale chamber. +1 on some pics. of your setup. I am using an absocold dorm fridge for my chamber and although I haven't fermented in it yet, as I am just finishing my project, I was able to get the temp. down to the mid 40's without any thermal mass inside. Here's a link to my build if you are interested.

http://www.homebrewtalk.com/f51/hoppos-rustic-fermentation-chambers-ale-lager-301274/

Good luck!

 

I will try and get some pics of the project up soon. I bought this 4x8 sheet of the 1/2" insulation thinking that I'd easily be able to put 2 layers of the stuff around the inside of the chamber. Well, amazingly, I've got 1 layer finished and there really isn't that much more insulation left so I'd have to go buy another 4x8 sheet to put another layer in. It was more expensive then the thicker foam board and the Home Depot guy said it had a higher R value so that's why I went with it. Now I'm thinking of buying the cheaper 1.5" foam board and putting that around the outside as it would be easier than crawling in that chamber for a couple hours and would fill up the gap between the top of the plywood and the top of the 2x4 framing. It'll all make much more sense once I post some pics. I guess I should of just gone with the 2" foam board right off the back. I just thought the higher R value would be better. The R value of the stuff I used is only 3 and I've read on here that some guys are using stuff with an R value of 9. Where do you get that insulation?

 

I get the polystyrene (styrofoam) insulation at HD. It is 3/4" thick panels and has an R value of something like 3.4 each. It comes in 18" x 60" sheets with 6 per pack and it's dirt cheap compared to the rigid foam insulation. With enough layers, it does the trick. My thread has the exact R-values and number of layers I used in each chamber. I think that I did something like 5 or 6 layers in my lager chamber and with the R value of the plywood, I was somewhere around an R 20ish. Just need to be sure to tape the seams and caulk all of the corners between each and every layer. I went lighter on the insulation in my ale chamber, somewhere around R 15ish I think.

 

Here are the exact sheets I'm using:

http://www.lowes.com/pd_304089-210-...L=?Ns=p_product_qty_sales_dollar|1&facetInfo=

The 1" sheets have an R value of 5, and the 1/2" sheets have an R value of 3. I have 1 sheet of 1", and 2 sheets of 1/2" around the sides, for an R value of 11.

For the top and bottom, I have 3 sheets of 1", and 1 sheet of 1/2", for an R value of 18.

I also caulked any gaps between edges, and then taped all the corners. I am debating whether or not to use the aluminum tape over every interior surface, both for looks and to help protect the foam. Its just a pain in the buttocks to cover the interior with 3" strips of tape...