...if electricity is a big issue, do yourself a favor and modernize your home... i swapped out all my lights to cfls (not all at once but over a month) and saved about 15 dollars right off the rip... i also weatherstrip and caulk EVERYTHING so it is easier and cheaper to maintain the enviroment...

if heat is an issue... ventilate.... suck COOL air into your room, near the lights... of course exhaust should be near the plants for smell and the bulbs for heat...

and... they do sell little 5k btu 90$ a/c's at lowes.... not that expensive to run