With the Michigan winter creeping in, I knew that I needed to do something to replace my makeshift fermentation setup that involves a bathtub and a space heater. The heater keeps the bathtub warmer than the rest of the house relatively well but it isn't very energy efficient and looks stupid when guests come over. My basement gets pretty cool in the winter and stays within ale temperatures even in the summer so I decided I could get away with only heating and not cooling in this setup.
I figure my costs of this are relatively cheap and should pay for itself over time. Below are my costs and estimate costs once I have my 2 stage temp controller working. I did not include the false bottom costs since I already had the material and it is not absolutely necessary since you could tape the heat cable to the walls of the chamber if you wanted.
-R7.5 (1.5 inch thick) Foam Board 4'x8' = $20
-2 tubes of Liquid Nails (already had on hand)= $0 (around $5 if you have to buy)
-23' of 50 watt ZooMed Reptile Heated Cable = $15 (on clearance)
-2 stage Temperature Controller = $40 (to be built)
The foam board I bought was already perforated to be easily divided into two 2' x 8' so I decided to keep all of my dimensions based on a 2' footprint.
I cut all of my foam sections as follows...
Top and Bottom - 24"x24"
Front and Back - 24"x28"
Sides - 24"x31"
I then glued the heck out of this when connecting the sections and used some duct tape to hold sections together until glue was dry enough (about a day)
To give the lid a little better fit when it is in place I added some of the extra foam across the top so that the lid would sit more flush and be a little more efficient.
Once I had the foam box done, I decided to make a false bottom out of some scrap I had and wind the heating cable underneath so that the heat would rise up. I made some swiss cheese like holes so that the heat would have less resistance against the wood.
When inserted into the fermentation chamber, it looks like this and I can actually fit 2 carboys if needed with blow off vessels. After I took this picture I added some weatherstripping to the top to help seal it a bit better when the lid is on...
Here is a picture from the outside, nothing fancy but shows the way my sections are attached to each other...
The box heats up relatively fast, about 10 degrees in 10 minutes and holds heat pretty well.
I plan to add some weight to the lid to hold it more tight to the other sections and also cover the top with a thick blanket to hold as much heat as possible.
Either way, this is going to save energy and some bathroom space, hopefully some of you can get something out of this. Let me know if you have any questions!