HighTillIDie is right! Cannabis CRAVES light. Just be careful of not only room temp, as your already aware, but also the heat intensity at the plants' closest point to the light. If it feels very warm at all, you may start to see evidence of heat stress on your plants. The easy test for that is ....if it feels uncomfortable on the back of your hand at a certain distance from the light, then its too hot for your plants there too.

F.W.I.W.....I have one strain in my room now that has to stay waaay cooler than the others. It heat-stresses easily. But I think it's genetics are deteriorating. The plant's a pain in the ass to keep.