http://www.cleverscampcamp.com/adult-sleeping/

How many hours is an adult iguana sleeping?
My iguana is 4years old and most of the day is sleeping. It doesn’t eat much but its color looks ok . what do you think?
I have had a green Iguana for eight years mine is around 6.5 feet long and he really sleeps more than my other reptiles and sleeps quite a bit but It is usually awake a good 8 hours of the day. a lot of the time when they bask they fall asleep and when you have a big enough enclosure it gives them room to explore and run around and climb. I have a greek tortoise living in the tank with mine and they eat together and everything it is pretty cool.I would assume your iggy’s behavior is normal just based on the fact that mine sleeps a lot too.
3 chicks and one adult sleeping