Reflectix type material against van walls?

Gh0ztkid21 · 08-22-2016, 11:14 PM

I've been researching the reflectix (and similar products such as tempshield double bubble etc.) and in all my reading they say to install it with an air gap between it and the outside layer yet everyone's install in their vans they spray adhesive right against their van walls.

Why is that? I've read and seen demos where the reflectix becomes a conductor of the heat and transfers it to the inside of it when it's places right against the van walls.

I was thinking of maybe putting a layer glued directly to the van wall then some foam board inbetween the ribs of the van walls then another loose barrier of reflectix just glued at the ceiling and floor and hanging down the wall with an air gap.

Any benefit to that? Or maybe just go with one layer? Idk I've seen so many peoples builds with it so tight to the van maybe they know something I don't know? Or are they doing it wrong?

86Scotty · 08-23-2016, 06:38 AM

I think you are correct. I think they, or 'we' are doing it wrong. I know undoubtedly that you should have an air gap for it to work properly and I've done the opposite, more than once. Two reasons I think people, including me, have done this. First, it's cheap insurance, or insulation. Second, it's so easy to work with and it just seems logical to put something in between, so Reflectix wins. I recently had a Sportsmobile pop top apart and even they had a layer of Reflectix between the fiberglass roof and the interior ceiling, with NO gap whatsoever.

I didn't know about the it actually conducting heat when used wrong though! Perhaps I should check this out!

boywonder · 08-23-2016, 06:58 AM

I doubt reflectix is very efficient at conducting heat......it's mostly plastic (an insulator), and air (another good insulator)...with an incredibly thin layer of metal (radiation shield).

A simple experiment would be to wrap yourself up in a roll......if you get warmer it's an insulator.....if it feels cool to the touch and you are cooling off it's conducting heat from your skin.......

You don't actually have to do the above experiment.....it's a good insulator...the mouse-fart's worth of conduction won't matter.

Most insulation works in a fairly low-tech way......by keeping air from moving. bubble wrap, fiberglass, etc all work this way..reducing free convection. If you can keep a sealed air gap in the wall, that helps.

Gh0ztkid21 · 08-23-2016, 09:07 PM

Thank you. Yeah I wasn't sure I did watch a video where a guy takes it and places it on a pan on the stove. It transfers the heat where you will feel the heat a few inches off the reflectix. The. He takes the reflectix and holds it 5" off the pan and his hand above the refectix and feels no heat. But again when he touches the reflectix it's still warm. That's why I wasn't sure if it's best to put it right to my van walls or kind of just stick it to the back side of my plywood wall and push it up against to leave that air gap. Or go a step further and put it right against the van walls, then a loose layer against the plywood with an air gap between the 2

boywonder · 08-23-2016, 09:48 PM

youtube video? Can you post a link? curious....

rob_gendreau · 08-25-2016, 10:44 AM

https://www.reddit.com/r/vandwellers...is_air_gap_or/

The OP is conflating a radiant barrier foil (like in the video) with Reflectix which, yeah, has a radiant barrier but also those bubbles...which function as an air gap. And even then if you were to say wrap the van in just foil you'd still have an air gap between you and the foil (as when people place foil on sunny windows).

Bottom line: the demonstration in the video is NOT using Reflectix.

Gh0ztkid21 · 08-29-2016, 05:45 PM

Quote:

Originally Posted by rob_gendreau

https://www.reddit.com/r/vandwellers...is_air_gap_or/

The OP is conflating a radiant barrier foil (like in the video) with Reflectix which, yeah, has a radiant barrier but also those bubbles...which function as an air gap. And even then if you were to say wrap the van in just foil you'd still have an air gap between you and the foil (as when people place foil on sunny windows).

Bottom line: the demonstration in the video is NOT using Reflectix.

Yes that is correct sorry I thought it was refectix. So would reflectix not transfer the heat with the air gap it has? Or is that air gap not really big enough therefor transferring the heat as well?

rob_gendreau · 08-30-2016, 09:12 AM

Quote:

Originally Posted by Gh0ztkid21

Yes that is correct sorry I thought it was refectix. So would reflectix not transfer the heat with the air gap it has? Or is that air gap not really big enough therefor transferring the heat as well?

Reflectix won't conduct much heat, or a trivial amount. I dunno the R factor, but it's also not the most insulating of materials. It obviously doesn't have the thickness of other materials. It's virtue in some ways is the thinness though. I use it to block windows after I removed the curtains. In van walls I'd do what you'd do in your home, and get thicker material where appropriate.