Last year I tried the same thing - putting my ferrets in my very cool
basement - however, it's not a finished basement, and after a couple
of days, my ferrets started to 'smell'
My basement is not ferret-proofed either, so I will still bring them up
stairs to play, but then they seemed to have a worse time with the heat
and wouldn't play anyway.
SO, I brought them back upstairs, put 3 fans on them, closed the shades
in the dining room, and now they do fine.
I got an old litter pan, cleaned it up and filled it with water in the
center of the kitchen floor - now they use it for a swimming pool and are
keeping cool that way.
Spritzing them with a water bottle will help keep them cool also.
This is a good time to give baths - they dry to fast and love the cooldown
[Posted in FML issue 1232]