November 2007
Q: I have heard of a new reflecting paint you can spray on your attic roof to reflect heat and reduce energy usage. Can you provide more information on this paint and its effects?
Kevin Pierce
A: Some new reflective paints on the market are intended to be sprayed or brushed onto the bottom of the roof deck. The idea is to reduce how much heat absorbed by the roof radiates into the attic. The theory is that reducing the radiant heat load in the attic reduces attic temperature, in turn reducing the heat load to the conditioned space. Some studies do demonstrate a benefit.
We believe a better solution is a continuously tight air and insulation barrier between the conditioned space ceiling and the attic. Because most insulation does not stop air movement, improving air tightness first minimizes movement of air between the attic and the home. Then, properly installed insulation makes attic temperature less of an influence on the conditioned space. Reducing the air flow from the home to the attic and having adequate insulation will keep attic heat from getting into the living space far better than adding layers of reflective paint to the underside of the roof.
Creating a durable air and thermal barrier between the attic and the living space not only saves energy, it also makes the home more comfortable and reduces dust. Look for gaps in insulation, as well air leaks between the house and the attic, especially around pull-down steps, recessed lighting, plumbing, wiring and ductwork holes.
Source: TSE Services, a market research provider for electric cooperatives throughout the U.S., and Advanced Energy, a Raleigh-based energy research organization.