Shiny Side Up or Down.

[Genghis]

Ok the floor is about ready for insulation. I've been looking at insulation at Lowes and the 3/4 insulation that I want to put in has one side with "aluminum" shiny backing.

Should I put the shiny side facing down or facing up?



Genghis sends.

z

[Twigg]

Originally Posted by Genghis

Ok the floor is about ready for insulation. I've been looking at insulation at Lowes and the 3/4 insulation that I want to put in has one side with "aluminum" shiny backing.

Should I put the shiny side facing down or facing up?



Genghis sends.

z

If you are looking at R-Max, it is actually coated both sides it's just that one side is over-printed.

Generally, putting the foil face to the metal achieves nothing.

[ThunderstruckStudios]

Hey Genghis,

The shiny side is a radiation barrier. You get more radiation heat transfer at hot temperatures, so the best answer is shiny side facing towards the hotter side. Since that flips depending on the season, I'd recommend shiny side up to keep you warmer in the winter when it's warm inside and cold outside. In the summer, the bottom of your bus will always be in the shade and relatively cool.

To be honest though, shiny side up vs. down will likely make a negligible difference.

[Tango]

Read the fine print that is right on most any such insulation and they state that it makes no difference. Both sides are foil but typically, one is fully printed over. Just noticed this myself while adding some to my shop.