My response to this question is a question to you. Are there such things in the wild? I mean, lights.
Aside from the moon, chameleons will no naturally encounter a red light which provides heat.Chameleons need darkness to sleep properly. Also, chameleons can take low temperatures. An adult veiled or panther can take temperatures to the 50's.
Unless the temperatures go down to the very low 60's (60-62), I would not provide any heat at night, specially coming from an infrared bulb. If they do reach those low temperatures, I'd use a ceramic heat emitter, but i'd be very careful.