Warm summer months affecting your brewing temps for ale?
Don't want to setup a fridge or deep freeze for temp control?
I have a super cheap answer that'll cost you $20 to make, and harnesses some of your central A/C for cooling.
Head to Lowe's/Home Depot/big box hardware store. Head to the insulation materials, and buy a 4'x8' sheet of that pink extruded foam board insulation...the stuff they put up when they do siding on a house.
Then construct a simple 4 sided box, and a 5th piece to act as a lid.
Then simply position the box so it sits over part of an air conditioner vent. You'll have to adjust the position of your lid to allow air exchange so the box doesn't get too warm or too cold for the yeast you're using.
This was pretty much a proof of concept design. I will likely get some thin plywood and some hinges, and make something a little more solid...actually constructed, rather than using duct tape.
Then glue the insulation inside the box.
Here's a photo of what it looks like in my little spare bedroom/stained glass studio
and here's the thermometer showing a balmy 67.5F
its not for lagering but it'll keep your ales cooled off in the summer, and could be used for bottle conditioning some beers too.
*edited to add*
Forgot to mention, I keep my A/C dialed between 76-78F, so I'm getting a good 9-10 degree drop with the lid vented. when I had ti closed I was at 65F.
I would just add that this will work better if you can get a nice sized cardboard box like from a larger tv or a dishwasher, and then glue the foam insulation inside. it'll be a little more durable and hold the cold better.