dimming a light would be difficult. a better option would be to have a light mover, so you can cover more space with a single lamp, or if you have multiple lights you could get a ballast flipper so only half your lights run at the same time, then the flipper will change to the other light it's powering at the programmed interval (good flipper's are rare) or you could individually time them. if you had say 4 lights in a square room, you could run one lamp at a time for 3 hr per lamp, or 2 lamps at a time for 6 hrs, however you need based off the ambient temp. this way you could still cover the entire canopy, but put out far less heat