Fermentation Chamber...fridge or window AC unit?

I'm looking down the road to building an insulated fermentation chamber in our garage. Probably going to try and have it big enough to hold 4 x 6G better bottles or 6.5 gal. buckets. I've seen builds on here and elsewhere using either a dorm sized fridge or a window AC unit. I'm wondering what people have found to be the pros and/or cons of using either. The big pro for me with the window AC unit is I have access to 3 or 4 free ones, but if they won't do the job then I'll look to the fridge option. Our garage is unheated, so I may want to do a heating option in the chamber as well. We live in South Central PA, and our summers can get up into the high 90's, so I may need to keep fermentation inside 30 degrees cooler in the summer. It would be nice also to be able to get down to lager temps if needed. Just looking for opinions...TIA!

 

I got a huge old chest freezer for like $20 on Craigslist and I love it. Despite being pretty ancient it still holds temp really well, only has to kick on for a few minutes every hour even if it's hot as hell. I prefer it to a fridge because you can fit more stuff (I don't know how you'd get more than 1-2 carboys tops in a standard fridge) and because it opens from the top the cold air stays inside when I open it.

Just troll Craigslist/local papers for deals. You'll eventually find someone selling one cheap or even free if they're moving and need it gone ASAP. Not worth paying $200+ for a nice new one.