Re: [A/S] Rustoleum-Roof Painting

[Jerry Flanders <jeflanders@xxxxxxxxxxx>]

>I don't get it. If the top was shiny wouldn't it reflect all the light ?

No - not _all_ the light.

>Light and heat are different.

Actually, radiated heat and light are the same basic thing.

>The aluminum is reflective, but absorbs most
>heat. I painted mine white. Before if it was in the sun it was impossible to
>touch the roof for more than a second or two, after the temperature drop was
>unbelievable.

Yes, but be aware that different materials could actually have different 
reflective/absorptive characteristics at different "wavelengths" (the 
wavelength is the only difference between radiated heat from radiated 
light). You could actually have a surface that appears light/white to your 
eye that absorbs the sun's radiated heat well and becomes hot, or one that 
appears dark that reflects it. The solar energy industry developed some 
neat materials for practical household use that work similarly - solar 
windows that let light in but block heat radiation, for instance. 
Interesting stuff.

Jerry 4404   (retired Chemist)