home brew co2 is very helpful in higher temp conditions.
from growfaq:
A humidity and temperature gauge are essential in any growroom. Daytime conditions should be 70-80 degrees without co2, 80-90 degrees with co2 until the last two weeks when daytime temps should be kept between 70-80 and co2 can be reduced to adjust for the lower metabolism......
I always thought that was neat a kind of bandaid for when you just are having a
little problem keeping temp down.