I came up with a bunch of BLUE and GREEN commercial grade carpet squares that was discarded after after being replaced with new ones at the work site. These are the standard 24" square stick down carpet squares.
I put the BLUE ones on the floor of my off-road popup and the green ones on both beds wood pull out floors. I was very much amazed how well these helped out during the winter as well as the summer for maintaining a better temperature control inside the POPUP. Also during the winter months we put down the 2" square by 30-inch foam pieces like used with the house window air conditioner installs all around the tent bed floor where the fabric is looped in place. This also stopped up alot of small air gaps. I also used these same foam sections where the bed pull outs meet the POPUP solid wall. I also had air gaps in this area on both ends. You could see daylight through these areas before adding the foam sections in place.
The only drawback on the carpet squares was we do alot of off-road camping and the carpet on the floors sure did attract leaves and other small things from our boots. The previous vinyl flooring was much easier to keep clean haha...
We also have a 9X12 tarp over both bed ends that serves as a poor man GIZMO install. These tarps also help big time regulating inside temperature...
Roy Ken