Pro's and cons of adding a collar or putting a tower on the lid with the lines ran to the back so it can hinge to open? I am sure this has been answered but the search function here returned way to much...
Here was my list when I decided on the collar. See my couple of pics below of my collar build.
*With a collar, you are drilling holes through wood. With a tower, you drill a hole through the freezer lid, causing permanent damage. You can make freezer back in normal 'freezer' condition to sell if necessary if using a collar.
*Aesthetics: you can paint and customize the collar to look nice.
*Easy to open lid. A tower can be heavy and awkward when opening a lid.
*With a tower you also need more clearance behind the freezer, as a tower can bang the wall if it's too close when opening lid all the way. Taps in front mean you can put freezer all the way up against the wall.
*Some will say a collar adds a lot of weight when opening lid, and/or height when adding/removing kegs. I agree, but a remedy is the double hinged lid like in my design. I can open only freezer lid just to look around or pour from a picnic tap, or I can open entire collar+lid if I'm changing out kegs.
*Along with that, my hoses are attached to the collar, so if opening just freezer lid, they are not 'stretched'. With a tower, you need the extra slack to be able to open the lid.
*Temp. A tower can have temp issues, since it is 'outside' the freezer. With a collar, your taps are right up against the freezer. I put a fan below my shanks inside to help circulate and keep shanks cold. Worked like a charm.
*Clearance height. You may be able to fit an extra keg/kegs on a compressor hump if you have the additional head room that a collar gives you. This is the reason I put a collar on my fermentation chamber as well, I could fit another carboy on the hump with it, but not without it.
maybe someone can chime in with functional pros of a tower, but I really can't think of any. It does look cool, I'll give it that.
Entire collar up, for changing kegs, or getting hoses out of my way to work on something.
Just the lid up, for simply looking inside or using picnic taps.
Double hinge design
The extra head room in my ferm. chamber was necessary when using a blow off.