K I have to write a report on housing insulation. I'm trying to find out when people first starting using it. Any ideas?

Answer 1

I couldn't find anything online. But the earliest people who lived in caves had the best insulation. Other people have built homes of mud brick, bales of straw, etc. that provided good insulation long before modern insulation.

Answer 2

Also, houses made of sod.
http://www.google.com/search?q=sod+houses&ie=utf-8&oe=utf-8&aq=t&rlz=1R1GGGL_en___US321&client=firefox-a

Mud bricks are also called adobe and are still used in portions of the US Southwest, especially New Mexico.
http://www.google.com/search?hl=en&client=firefox-a&rlz=1R1GGGL_en___US321&hs=asG&q=adobe+houses&btnG=Search