What if you could simply roll a layer of paint onto your walls and increase the thermal insulating property (R-value) of your home? What if a can of paint could makeover a room on a budget and help keep its indoor temperatures cool? That’s what insulated paint manufacturers claim their products can do. The ability to reduce your energy footprint (and your heating and cooling bills) with a coat is a fascinating prospect—but the jury is still out on how effective insulating paint actually is. Read on to learn how insulating paint developed, how it purports to work, and if it’s worth a try for your next project.
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The notion of a paint to reduce heat transfer first arose at NASA in the hope of protecting the space shuttle from the extreme heat generated by reentry into the atmosphere. NASA scientists developed an additive that contained tiny glass spheres called “microspheres,” epoxy particles, and heat-resistant chemicals. The mixture was sprayed on the shuttle at the same time it was painted to form a protective coating.
NASA later partnered with a company called Tech Traders and, expanding on the original insulating technology, to develop an insulating powdered paint additive, known as Insuladd, which contains microscopic ceramic spheres said to form a “radiant heat barrier” when mixed with regular interior or exterior house paint. Today, Tech Traders owns and sells Insuladd.
Other manufacturers have since begun producing their own brands of insulating paint that contain either ceramic or glass microspheres—either as an additive or as a premixed paint product—both of which are marketed to homeowners for interior and exterior use. In addition to Insuladd, brands include Hy-Tech and Therma-Guard. Manufacturers advertise insulated paint as being able to reduce the transfer of both hot and cold temperatures.
While insulating paint purports to work as a result of the microspheres forming a thin, heat-resistant bond, it relies on relatively new science and, to-date, independent large-scale testing is lacking. There has been a handful of small tests, including one conducted by Cold Climate Housing Research Center, which concluded that in cold climates, the insulating paint tested would not “be effective in reducing energy costs for residential homes.” The Florida Solar Energy Center conducted tests on both standard and insulating paints and concluded that insulating paint had “no significant advantage over ordinary paints.” The Federal Trade Commission (FTC) cracked down on at least one company for misrepresenting its paint as being equal to seven inches of fiberglass insulation. As of yet, no R-value has been determined for insulating paint.
On the flip side, EnergyIdeas Clearinghouse, a non-profit publication, in conjunction with Washington State University and the Northwest Energy Alliance, reported that Insuladd paint reduced heat gain by “approximately 20 percent when fully exposed to the sun.” That means the paint could conceivably produce an energy benefit if painted on the exterior side of a house that faced the hot summer sun. The report also stated that when painted on interior walls, however, “reductions in heat loss and gain are negligible.”
When the goal is to reduce the amount of heat transfer produced by the sun, virtually any white or light colored paint will perform better than a dark paint on exterior house walls because light-color paint reflects heat away rather than absorbing it. But more importantly, so far there is no paint that will take the place of good insulating practices. Most local building codes require a specific amount of insulation, measured in R-values, for walls and ceilings. Your best bet is to follow a well-designed plan for keeping energy costs down, which includes installing standard insulation materials, such as fiberglass batts or blown-in cellulose filaments, in addition to installing energy-efficient windows and doors.
Homeowners can choose from two types of insulating paint:
• Premixed paint: Some manufacturers produce cans of insulating paint for both interior and exterior use. These paints are applied like any house paint, with a brush and roller. The only caveat is to choose a type of paint that is suitable for the environment and the surface you’re painting. For example, if you want to paint an outside wall, make sure to purchase an exterior paint.
• Paint additives: Insulating powders, which also contain microspheres, can be stirred into regular house paint. Additives are preferable if you wish to use a specific brand of paint—just stir them right in by hand with a paint stick or a drill fitted with a mixer paddle. The additive blends in easily in a few minutes, and the paint is ready to use as soon as it’s smooth and no lumps remain. Read the warranty that comes with your paint, however, which may be voided by using an additive.
A premixed gallon of insulating paint sells for around $40 to $55 dollars. Standard house paint runs $25 to $75 per gallon, depending on quality. A one-pound package of insulating additive runs $18 to $22 and will treat a single gallon of paint. A standard gallon of paint covers approximately 250 square feet and insulating paint manufacturers recommend applying two coats of paint for the maximum effect.
Though insulating paint might not live up to some of the manufacturer’s claims, it can be used on virtually any surface that would take standard paint. In addition to residential interior and exterior walls, a light colored insulating paint that reflects solar rays may be of benefit on work or storage sheds, playhouses, exterior propane tanks, and any other paintable surfaces that you’d like to keep a little cooler. While insulating paint is applied in the same manner as any other standard paint, with a brush or roller, the following tips will help you achieve the best results.
• The surface to be painted must be clean and dry.
• If you’re painting over a previously painted surface, scrape any peeling paint and sand the surface smooth before applying the new paint.
• Apply insulating paint when the temperature is between 55 degrees Fahrenheit and 85 degrees Fahrenheit.
• If you’re spraying insulating paint, remove the cartridge filter from your spray gun to keep it from clogging before painting. Although the microspheres are tiny, they can still clog a filter.
Maintaining an insulated paint surface is similar to caring for any painted surface. The tips below will ensure that the paint on your walls or other objects will last as long as possible.
• Wash interior painted surfaces with a mild mixture of warm water and a non-abrasive all-purpose cleaner, such as Pin-Sol (available from Amazon). Use a sponge dipped in the solution to wipe away dirt and grime, and then dry the surface with a clean cloth.
• Spray down exterior walls with a garden hose and a hand sprayer to remove the dust and dirt that can accumulate over time.
• Avoid using a power washer on exterior painted walls because the high pressure may remove the paint and could damage some types of siding.