Fermentation Chamber - A/C or Mini-Fridge?

ic3scrap3r · 09-24-2009, 08:30 PM

I'm thinking about building a fermentation chamber and using either an A/C window unit or a mini-fridge using the standard insulation style of build.

Those of you with experience with this, which of these do you think would be better, more efficient?

I would be interested in the Pros and Cons of both of these.

hamiltont · 09-24-2009, 08:38 PM

I went the AC route. Chamber is 3'W 4'L 6'T OD. Found a Haer 5250 AC unit at Wal-Mart on clearance. Has to be the manual control type, not remote. Moved the temp sensor from the front of the unit to the back to keep it from shutting off prematurely. Regulate it with a Ranco control. Used 2 layers of 3/4" insulated sheathing. Gets to 32F in just a few minutes.

TheBelly · 09-24-2009, 08:42 PM

IMHO - It depends on the beers you brew most, and volume that you are cooling.
Note I have no experience with either of these but, I would think that if you are lagering a mini fridge is going to stand up to the cooling demands much better as long as you are not trying to keep a large volume at 48 degrees. Where as window AC unit will handle the Ale temps better. In addition a window A/C moves a fair amount of air without adding any other fans, so may be easier to cool larger volumes.

**lamarguy** · 09-24-2009, 08:58 PM

Have you considered a frost-free upright freezer + Love controller? You can find upright freezers on Craigslist and scratch-dent models at Lowes/Home Depot pretty easily.

Pros -

Already designed to be an energy efficient cold box.
Frost free design (unlike an A/C unit or mini fridge).
Sheet metal is most likely sturdier and lighter than a homemade box.

Cons -

May cost slightly more than an A/C unit build (depends on source).

I've purchased two brand new scratch-dent upright freezers over the last couple of years, one for $300 (13.7 cu ft) and $350 (20 cu ft). They make excellent fermentation enclosures.

leboeuf · 09-24-2009, 09:01 PM

The ac generally has realllllly high btu/$ number and is meant to cool large areas. I bypassed the thermostat on the unit and use an external controller. I haven't had any issues maintaining 45F with my 5000btu window ac.

**samc** · 09-24-2009, 09:06 PM

+ Haier 5200 btu from Target on sale about $75, to maintain a 65F ferment the thing barely kicks on. Added $20 heater for the winter months coming up. About the same size fermentation area as poster#2. Also moved the thermo to the outside of the cabinet, took about 5 minutes to get that done.

MMW · 09-24-2009, 09:06 PM

Whatever you find cheap gets my vote. That even includes freezers if you can find one (I can't since all the hunters around here snap 'em up).

Cheap is why I went with a dehumidifier

leboeuf · 09-24-2009, 09:06 PM

Added my build thread to my sig if you're interested...

**Cpt_Kirks** · 09-24-2009, 09:29 PM

I used a 4.5cf Haier fridge and some 2" pink foam board. It maintains a steady 62*F or 49*F with the fridge almost never kicking on...and that was in the hot part of the summer.

I don't even have the lid attached, it just sits on top. The box is big enough for two six gallon Better bottles and a couple of cornies.

ThreeTaps · 09-24-2009, 09:41 PM

This brings up a really good point. I have an A/C unit that I was planning on using for my garage closet, however it's a digital one that has a remote with it. You don't need the remote to operate the unit, but it doesn't have a dial that you can set to an "on" position so it turns on whenever power is sent to it.

This basically makes my current A/C unit non functional for my fermentation chamber, eh?

...Unless of course I can take it apart and find the current sensor, then splice in about 5 feet of extra wiring to extend it to the middle of the cabinet.