I have my chins in a room with no windows. I have lights on automatic timers, 12 hours on 12 off. They do fine in the dark.
Humidity needs to be compensated with cooler air conditioning. My chins stay at 65 because it is SO humid here, that is comparable to 72 elsewhere.
Smells should be kept away from chins, no scented bedding, scented dust, etc. They have sensitive sense of smells and it can be very stressful and even dangerous for them to have certain smells around all the time.
I have found my chins like the radio on, it helps with all the little noises around and ever since we have been having so many thunderstorms, I leave it on all the time. They like classical or country, haha.