Roof design improves heat efficiency in the home
A new roof and attic system designed to keep homes cool in summer and prevent heat loss in winter is being tested at the US Department of Energy's Oak Ridge National Laboratory (ORNL).
The system improves efficiency using controls for radiation, convection and insulation, including a passive ventilation system that pulls air from the underbelly of the attic into an inclined air space above the roof.
"Heat that would have gone into the house is carried up and out," explained Bill Miller of ORNL's Building Envelope group. "And with a passive ventilation scheme, there are no moving parts, so it's guaranteed to work."
ORNL claims the new roof system can be retrofitted with almost all roofing products. At the heart of the design is a foiled covered polystyrene insulation that fits over and between rafters in new construction or can be attached on top of an existing shingle roof system.
The cost of the system is currently $2000 (approx. £1200), with homeowners expected to save $100 (approx. £60) per year. Looking to the future, Miller and his colleagues are now working on designs with lower initial installation costs and greater cost-effectiveness overall.
