There are a couple different types of tent in use over in the sandbox - the majority are canvas shells with some sort of tyvek-like inner shell...and ductwork for A/C. Some of these have been foam covered. There are also shelters which are more heavily insulated sans foam. A lot of the troops are living in containers or wooden structures, some in local buildings.
The Hajjis typically sleep on the roofs, since it is the coolest place at night.