Bringing up humidity will lower temperature and the other way around in a given setting.

To raise humidity without any gadgets you can simply hang a towel, or something like that, dipping down into a bucket of water and let one of the oscillating fans blow on it on every cycle or just dedicate one fan to the towel all together if you need more or put up more towels (sails).
We call that the "sail-method" here and for me it too my temps down from about 86 to 78 and the humidity up from 45-61%.
Nothing else changed.
I grow in a 100*100*200 (centimetre) grow tent by the way.

Puffzter