You can either cover his home to help keep heat in, or purchase a night light for him. However, that doesn't mean it is good for them. A good diet consists of variety and nutrition. Contrary to popular belief, iceberg lettuce is the worst thing you can feed him. Romaine lettuce is a better choice, but still not the best.
Iguanas love squash of any kind.
Spinach is high in iron, but should be kept at a minimal level as it can deplete other vitamin and mineral levels of your green buddy. Hibiscus flowers are a summertime favorite of iguanas. They love oranges and cantaloupe as well as honeydew and watermelon. Tiny dinosaurs also enjoy berries of all sorts, just be careful about the seeds. Grapes cut in quarters without seeds provide needed moisture.