Hi,
I live in Abu Dhabi where currently the temps are up to 47 degrees celcius. I also have 3 large sulcatas who happily live outside all the time. Because they were born here, and of course are used to the temperature, I generally let them burrow wherever they want! They have now dug a short tunnel that opens up into a sort of cave where the three of them (all females) sit together throughout the day. They are generally up and about, eating the lawns at 6 a.m. then go into their cave throughout the day and come out again at about 4 o'clock when it's still daylight but not direct sunlight on their part of the garden.
Please do not take them into the house, and then out again - the change of temperature could make them very ill. These guys are very hardy and adore the heat so be assured that if they didn't like your igloo, they will definitely go dig one for themselves!
Just as a precaution to anyone who has these beautiful animals, let me tell you that last year when we first came here, I brought a beautiful 11 year old male with me - I'd had him all his life at home in the Mediterranean. However, once he met one of my current girls and fell in love, she started teaching him how to dig these burrows because they were mating twice a day (they were both 11 years old and weighed about 35 kilos). One day I got up, went out to see them only to discover that the sand had capsized over him during the night and he had "drowned" in sand ...... the landlord next door had left the drip irrigation on; Hercules had decided to bite through the pipe probably to get more water, so that it was gushing water all night, and the sand got too heavy. I had to dig him out of 3 feet of wet mud the following morning - I still tremble when I remember this sad day.
Sorry I went on too long ..... these creatures are my babies and I like to give advise about them from my long experience with them.
j x