Radiant barriers need an air gap - Any disagreements?

Is there anyone that thinks that a radiant barrier can work without an air gap?

Could you please explain what is wrong about this video.

What this video explains

Radiant Barrier Foil Insulation - Why Is Air Gap or Space Required?

Low-E is a type of radiant heat barrier?

Radiant heat requires an air gap
Emissivity also requires an air gap

Without an air gap, you have conductive heat transfer.

Conductive heat is when 2 materials touch each other
and so heat is transferred.

Demo - Why it will not work under shingles

Proof That Foil Radiant Barriers Don’t Work Directly Under Roofing Shingles -…

Amen, you do need an air gap.

Here is another video about the need for the gap

I’ve heard that the radiant barrier sheathing works very well but it seems that the air gap is necessary for a dramatic improvement.

I agree with the video because it seems practical.

I’d like to see some tests and data to show how much radiant barrier sheathing improves over standard. The another showing the difference between an air gap radiant barrier and radiant barrier sheathing.

I can say that with whatever radiant barrier… Diagnosing leaks becomes a tad more difficult.

Here ya go!