Ductboard Cooler for low fermentation temps

[Joesf35]

I'm trying to create an insulated cooler with a lid, (lid will have hole for airlock), for keeping fermentation temperatures down in the 60s. I want to put a few ice packs in the cooler. I live in south florida and the apartment is at 75+ usually, and my first beer was done bubbling through the airlock in 2 days! Is a small sheet of foil faced ductboard the least expensive way to go? I was thinking about a cardboard box wrapped in insulation but was worried about sweating inside ruining the box... very humid down here.

Thanks in advance!