Radiant barrier paint
Son_of_a_Tradesman
| Posted in Energy, Heating & Insulation on
I’ve found several vendors offering paint modifiers consisting of glass micro balloons who claim significant reductions in heat transfer. Does anyone have experience using them? Are the products sold as containing a vacuum the most effective? Will the micro balloons used as extenders or fillers for fiberglass work? I’m trying to hold heat in a living space (as opposed to trying to block unwanted heat gain). I’m a little uneasy purchasing based only on the advertisers assertions and testimonials.
Thanks,
SoT
Replies
Son,
Radiant barrier paint (for residential purposes) is a scam.
Report exaggerated marketing claims to:
Hampton Newsome
Division of Enforcement
Bureau of Consumer Protection
Federal Trade Commission
600 Pennsylvania Avenue, N.W.
Washington, DC 20580
[email protected]
I have trouble believing that a film a few microns (?) thick has much insulating value. (Maybe if you slathered on fiberglass microballoon fillers an inch thick?) I suppose if you painted something with shiny aluminum paint over some microballons, you'd get some small barrier effect to radiant heat, but I still think it would be so small as to not be noticeable.
We are talking about radiant barriers and not conductive thermo insulation.A radiant barrier only needs to be a few micros thick to work. It is the infrared reflectivity/emissivity that is needed.Aluminum foil and metalized mylar are good radiant barriers.IIRC to be designated as a radiant barrier it has to be rated 95% or higher.But there is an lower class that is maybe call radiant coatings or something like that. I think that they need to be rated 75% or maybe 85%. But many of the radiant barrier paints that a specifically formulated for that purpose don't meet even those lowered requirements.No telling what you get in an additivity.Now radiant barriers can be a useful product, but they work best where there is a large difference in temps. The best application are for roof "insulation" in the south.Now some of the "testimonies" for the radiant coatings are for industrial applications where you have hot tanks. Again a large temp difference. In general, however, they have been drastically oversold for typically residential appilcations where even uninsualted wall construction has more affect than any radiant barrier, much less a radiant paint.The only residential application, other than roofs, where they are useful is in lowE windows. And there you have metal layers that are so thin that you can see through them..
William the Geezer, the sequel to Billy the Kid - Shoe
Another application is in kilns. There are paint on coatings that enable plywood to withstand
2200 degree surface temps. These are very expensive and don't have residential paint qualities
(washable for instance). They also don't seem to last very long.
Scams. Radiant coatings can work ... in theory and in the lab. Houses are neither theoretical nor do they exsist in or are constructed in laboratory conditions.
Bill Hartman made some good notes to put this in perspective in an earlier response.