This is indisputable radiant barrier foil works!įurthermore, it is actually difficult to install the foil wrong.
So long as the foil is installed somewhere between the roof/rafters and the insulation, it will reflect 97% of the radiant heat. The main reason you should consider the foil over the paint is because with the paint you are basically counting on the product to deliver results, while with the foil you are simply needing the person (which may be yourself) to get the installation done. In order for paint to come close to the tested emissivity rating, the wood surface must be primed with a primer/base coat of paint first. Your attic is made up of porous wood that loves to soak up paint instead of keeping it on the surface to create a smooth, shiny film, which would be required to be fully effective. Some paints claim to be award winning, although what award they are receiving still remains to be identified or significant.Īdditionally, the paint tests were conducted on perfectly smooth samples, applied under laboratory conditions these conditions are different than your attic. Notice that the best paint still emits 22% of the radiant heat, compared to only 3% for radiant barrier foil. Below is a chart with some test results by RIMA (Reflective Insulation Manufacturers Association) which did independent testing on all the different radiant barrier paints. In fact, none are true radiant barriers since they all reflect less than 90% of the heat which is the definition of a true radiant barrier technically they are reflective coatings.
Reflective coatings comparisons chartMany companies have developed radiant barrier spray paint. With the cost of radiant barrier foil only being less than $0.13/ft, it’s obvious it is not only a better product, but a better deal.ĭifferent Brands of Paint & Testing Results Most people who try to do it themselves will actually blow too much paint and the material cost alone will be over $0.30/ft. Forget about painting with a roller because it is impossible since there are thousands of nails sticking through the roof deck additionally, using a paint brush to manually paint it on would take forever. The fumes are noxious, you must use a VOC respirator, a high-end airless spray rig, the proper size spray tip, and the proper pressure to get correct coverage and eliminate clogging. Radiant barrier paint spray is not a good Do It Yourself (DIY) project. The typical consumer can’t tell the difference between a good installation and a poor job without testing. *Cutting is when water is added to paint it is cheating to cut costs.Īs a result, the true effectiveness of radiant barrier paint installed by many contractors is really only about 15-40% reflectivity.
There are some contractors (even large ones who advertise heavily) that will cut* the paint with water in order to extend the coverage. The paint is being applied with the correct coverage (many contractors put it on either too thin or too thick). The rafters are being sprayed completely (this usually costs more when you get an estimate). Getting good results with radiant barrier paint assumes a couple of things: When the paint is installed correctly, it will reflect about 75% of the radiant heat and can be a very good product. The best radiant barrier spray spray is only available to commercial contractors, and is an environmentally safe, water-based low-e paint called HeatBloc-75, Radiance e.25 or Lo/MIT. Once the clear paint dries the aluminum powder forms a layer of aluminum. While not all radiant barrier paints are the same, basically they are made by grinding pure aluminum into a fine powder and then mixing it into clear paint. "Radiant barrier spray-on paint is essentially liquid foil. Here is a fairly good article on the subjecct.
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