My CT has only Reflectix, with taped aluminum outside panels and 7\16" Advantech inside. I checked it was there yesterday. Nicely factory installed. 1" air gap.
I am running tests today and some last week. The white CT is facing south into a bright sun today. Lots of snow reflection. I have a remote thermometer in it. All windows and roof vent are covered in Reflectix also. Floor is 3/4" Advantech. No Sun getting inside.
Reflectix has no R value at all as far as I can find. So maybe R2 walls and R1 floor. Today the CT inside temp is exactly following the outside air temp. Sun is doing nothing, it's radiant heat is being reflected. Night time tests of heat rise inside with 1350 watt electric heater has been getting the inside up as far as 80 with outside temps in the teens. Heat is being reflected back in.
At noon I am turning on the electric heater from inside my warm home and will see how long until I can go play house. Meaning above 60 F.
I had wanted the factory to spray foam the underneath, They refused. I have noticed some high-end RV's use Coroplast (corrugated plastic) to cover the bottom of the trailer. Seals everything in and adds an airspace...I am considering doing that. Coroplast is cheap, tough and easy to work. I might stick it up with Scotch 3M .
https://www.scotchbrand.com/3M/en_US/sc ... 497&rt=rud CoroPlast
https://www.homedepot.com/p/Coroplast-4 ... AQodtqUBdgI have used the 3M for lots of things. Hangs Coroplast signage anywhere for years in the North. I think it would be too strong to remove if it was used in a continuous strip on a CT bottom.
It would slow air infiltration underneath thus keeping the floor warmer if heated. Maybe add Reflectix between the floor and the Coroplast.
Have you ever slept in only a sleeping bag on the metal floor of a pickup? I have in 25 F. It was very cold. The cold seemed to intensify. I soon built a platform bed and it was much better.
Now its noon and 26 f inside the CT with 1350 watt just turned on. I went outside for a minute and damn near fell. My cement pad has thin snow covered in ice and very slippery...I won't use salt.