Winter Energy Savings

There’s a chill in the air, every retail store you know is preparing for the Holidays!  Have you missed your re-roofing window?  Absolutely not.  Even throughout the winter, as long as we have windows of nicer weather and the temperatures don’t dip drastically, roofing can continue year round.  You may actually be able to take advantage of extra inventories with additional savings.  More importantly considering the rising energy costs to both heat and cool your home a metal roofing system can make all the difference.

Research Shows Metal Roofs Reduce Attic Cooling

Data collected during one full winter season and one full summer season of testing by the Dept. of Energy’s Oak Ridge National Laboratory shows a significant benefit to using dynamic metal roof assemblies to reduce energy use when compared to a single component shingle roof.

The multi-year research project is supported by the Metal Construction Association, the largest North American trade association representing metal building component manufacturers and material suppliers. The program is aimed at evaluating the future needs of advanced metal roof and wall assemblies.

The first phase evaluated the affects of different roofing system assemblies on attic temperature control and attic-generated heating/cooling loads. One roof system featured sustainable retrofit technology consisting of metal panels integrated with PV laminates and a phase change material heat sink. The other used a conventional shingle roof as a basis for comparison. Analysis of data collected from winter 2009 through mid-summer 2010 reveals significant improvements in the thermal performance of the attic when the roof consists of metal panels integrated with PV laminates, phase change materials, rigid insulation and above sheathing ventilation.

“These findings highlight metal’s role in improving building envelope performance, and are quite comprehensive since they cover temperature extremes and include the use of phase change material. Although the parts are all conventional materials, their assembly is unique. They confirm that a roofing system made of multiple components can out-perform single component roofs for both heating and cooling. It also indicates the long-term value of integrating metal roofing with photovoltaic technology,” says Scott Kriner, LEED AP, MCA’s technical director.

The test’s two main comparison parameters were attic temperature and attic-generated heating/cooling loads. The findings for each included:

Attic Temperature: During winter, the minimum nighttime temperature in the dynamic metal roofing assembly attic was, on average, 16°F higher than the shingle attic temperature. This suggests less heat loss is occurring in the metal roofing assembly. Conversely, the maximum summer daytime temperature in the dynamic metal roofing assembly attic was 20°F lower. This indicates the ability of the system to reduce the solar heat gain into the attic space.

Attic-Generated Heating/Cooling Loads: The dynamic metal roof assembly enabled the reduction of both cooling and heating loads, compared to the shingle roof.  During winter, there was a heating load reduction of 30% with the dynamic metal roof; and in the summer the cooling load was reduced by 50%.
Source:  Metal Roofing Magazine – September 2010