Help! it's hot!

It got hot this weekend. 85 degrees inside our house! (with fans blowing, etc. This is the best we can do.)

But little Obed won't drink water. Not in his bottle or in a cup. (Though he hasn't really mastered any type cup yet). I tried to find pedialyte to prevent him from getting dehydrated. But could not find it. It is appropriate for heat dehyrdration?

He's not hardly eating at all (solids) and sometimes will drink lots and lots of formula (12 oz in one sitting!), and sometimes won't take any at all.

How do you keep your little ones hydrated in hot summer?