Rooftop savings

Homeowners could see their summer utility bills fall by eight percent or more with a new roof and attic system being developed at the US Department of Energy’s

(ORNL).

According to ORNL, roof technology has not progressed substantially in hundreds of years, but that is changing with the use of active thermal mass components, reflective pigments and coatings, subventing, radiant barriers and other techniques being tested by a team led by Bill Miller and Jan Kosny of ORNL’s Building Envelopes group.

Their prototype roof and attic system works by reducing attic temperatures by about 22^o F during a typical summer afternoon and decreasing the amount of heat that gets transferred through the attic floor to the living space.

At the heart of new roof system is a proprietary inorganic phase change material sandwiched between two reflective surfaces made of aluminium foil. This material is installed as a dynamic thermal barrier between the roof and attic area, creating separate air channels between roof rafters. The configuration is compatible with traditional wood and steel framing technologies. Moreover, the new phase change material overcomes problems that are said to have plagued phase change materials for the past 40 years.