Carl, obviously if its a business computer, they aren't really designed for super cooling, because they don't run super hot however dust collecting inside can have some direct results on accumulated heat so getting some compressed canned air, taking it outside, removing the cover and carefully blowing the accumulated dust out will help.
If you don't feel comfortable doing that yourself, ask a tech to inspect the machine for you and see if you have a dust buildup problem, because you'll have to shut your system down to do it, and you probably have an auto backup system.
You could lower the building heat to maybe 60F or so at night, but the lower you take it the costlier it will be to raise it back for employee work comfort level, but if you have a restroom in the building do not turn off the heat period, especially if you're in freezing temperatures at night.