Efficient roof-and-attic system for homes undergoes field tests
Share
A new kind of roof-and-attic system field-tested at the US Department of Energy’s Oak Ridge National Laboratory is claimed to keep homes cool in summer and prevents heat loss in winter.
The system is said to improve 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,’ said 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.’
According to a statement, the new roof system design can be retrofitted with almost all roofing products. 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.
Poorly sealed HVAC ducts leak conditioned air into an attic, which typically costs homeowners $100 (£62) to $300 per year based on ORNL computer simulations.
To address the problem, homeowners pay up to $8,000 to seal the attic with spray foam, which can save upwards of $460 a year. For less initial cost and the same number of payback years, homeowners can retrofit the attic with the new design for about $2,000 and save $100 a year.
Looking to the future, Miller and colleagues are working on designs with lower initial installation costs, and greater cost-effectiveness overall.
A paper, Prototype Roof Deck Designed to Self-Regulate Deck Temperature and Reduce Heat Transfer, was published by the National Roofing Contractors Association.
Authors include W Miller, Stan Atherton and Russell Graves of the University of Tennessee, Knoxville, and Billy Ellis of Billy Ellis Roofing.
Readers' comments (3)
Andrew the Taxpayer | 12 Sep 2012 9:03 am
This sort of thing, along with Showersave [google it] and solar water heating, should be mandated on new build and rebuild properties. Technology like these should be VAT-exempt to encourtage uptake.
Otherwise we're going to continue to have the worst housing stock in the developed world.
Unsuitable or offensive? Report this comment
Happy Attics | 12 Sep 2012 2:48 pm
I agree Andrew, I think that's a good way forward for new builds.
Unsuitable or offensive? Report this comment
Jonathan | 16 Sep 2012 11:24 pm
Whats so special about this roof, I might be wrong but its used in the UK and has been for some time. It doesn't work, you cannot achieve airtightness, and its costs a lot over here to fit. Rigid boards are hard to cut and any movement in the building structure leaves gaps and cold spots. You are better off with a warm roof construction and spraying on the membrane using a breathable foam.
Unsuitable or offensive? Report this comment