Radiant Barrier Materials (Metals and Such)

retrodog

I'm working on some sort of retractable cover for my solar array panels (PVs or whatever the cool term is these days) and would be able to make it a dual purpose function if it also functioned as a radiant barrier. So how good is aluminum? The radiant barrier plywood that I helped a friend install on his roof seemed like it just had a thin layer of aluminum foil. Is that all it is? And if so, would a slightly thicker layer of aluminum work well too? Or is this just a waste of time? Just wondering.

BB.

Re: Radiant Barrier Materials (Metals and Such)

I have read "glowing" reports about radiant barriers--but I think they have there limits too... Heat loss through conduction (aluminum is very good at conduction) and air infiltration make a big contribution too.

Thicker aluminum will not do anything to help reduce radiant heat loss (that I am aware of). Mylar coated with very thin metal (aluminum or even gold for space flight) only has to be "thick enough" to reflect the IR light. Any more will not help at all.

Also, be very careful with installing radiant heat barriers. Australia has a government home insulation program that has succeeded in burning down ~100 houses (or more by now?) with electrical shorts. Also, I believe they have killed a few installers too.

Given that the Environment Minister faced a censure motion in parliament yesterday over a scrapped scheme under which 160,000 homes have been given shoddy ceiling batts, 80,000 homes have been installed with potentially dangerous insulation, 1000 roofs have been electrified, 93 houses have caught fire and four people have died, it may seem hard to believe things could get worse.

-Bill

Dave Angelini

Re: Radiant Barrier Materials (Metals and Such)

Yeow Bill, picked the wrong day to play around in the attic:-)
Also keep in mind the radiant barrier on south and west walls in the attic. Costco has a radiant insulation program that adresses the walls and it makes sense to me that it could really help.