Optimum temp @ top of plant closest to light is 70 degrees. Therefore, your room must be much cooler than 70 degrees in order for the temp to be 70 degrees at the top of your plants. Air cool your lights with turbo exhaust fans w/glass. Make sure your air cool system is sealed so you don't loose CO2 if you're using it. Have wall-mounted fans blowing across the plants inbetween your light and plants and lastly and most important, GET AN AIR CONDITIONING UNIT! lol There are also water cooled lights as well that emit no heat too!
Get the lights as close to the plants as possible w/o the temp at the top of the plant exceeding an optimum 70 degrees. (max 80 degrees)