Study on Weather Barrier’s Contributions to the Energy Conservation of Building
American National Institute of Standard and Technology (NIST) has made a study on the impact of air tightness improvement upon energy consumption of building and issued a report in 2005 entitled Investigation of the Impact of Commercial Building Envelope Air tightness on HVAC Energy Use （ Report No: NISTIR 7238） .The study made a simulated analysis using 3 kinds of building types (2-floor office building, 1-floor single house and 4-floor apartment) distributed in 5 climatic zones ranging from temperate zone to frigid zone in 5 cities in USA as its objects. The study shows that the building with weather barrier is maximally 40% higher than that without weather barrier in annual heating and cooling energy cost savings.
Engineer Bruce A. Wilcox and Professor Theresa A. Weston from American Society of Heating, Refrigeration, Airconditioning Engineer (ASHRAE) made a comparison of air leakage (penetration) between the house using DuPont™Tyvek®（ Tyvek®） weather barrier for improving its air tightness and the house using the ordinary weather barrier (damp proof paper) in California in the article titled Measured Infiltration Reduction in California Production Houses Using Housewrap.The air leakage (infiltration) areas of four pairs of houses located in California built in 1996 and 1997 by the builder were measured, of which, each pair of house are of the same structure with one wrapped with Tyvek®（ Tyvek®） weather barrier and the other wrapped with two layers of ordinary building paper (damp proof paper).The tests indicate that replacement of the two layers of building paper with Tyvek® reduced the specific leakage area (SLA) in the four houses by 7% to 18%, with an average reduction of 13%.
In the summer of 2005, Phil Childs， Jerry Atchley， Andre Desjarlais and Achilles Karagiozis from the National Lab in Tennessee, through three different practices on roof in the America National Atmosphere Exposure Test(NET) Lab, made comparisons of the differences in roof energy consumption among: 1) roof without weather barrier, 2) roof with DuPont Tyvek weather barrier of ordinary type, 3)roof with DuPont Tyvek weather barrier of reflective type and released a report titled A comparison of weather barriers installed on the roof of NET(America National Atmosphere Exposure Test Lab(NET) in Charleston, South Carolinaand on the roof of DuPont company. The result shows that the temperature of the roof with the weather barrier of ordinary type is about 7% lower than that without such weather barrier, and the temperature of the roof with the weather barrier of reflective type is around 12% lower than that without such barrier.
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