SYMPOSIA PAPER Published: 11 October 2017

Airtightness of Common Wall Assemblies and Its Effect on R-Value


One key method of decreasing the energy consumption of a building is to make it more airtight; about 13 % of the energy used in residential buildings is due to air leakage between the interior and exterior environments. This air leakage not only affects the energy consumption of a building in this direct way, it also makes the existing insulation in envelopes less effective. To understand how air infiltration affects the nominal R-value of walls, Oak Ridge National Laboratory first tested 23 homes in two climate zones using a guarded blower door method to determine the in situ leakage rate through walls of whole houses. Based on this data, an approach for determining an effective R-value that takes into account climate, air leakage rates of walls, and nominal R-value of insulation was developed. This effective R-value is a useful performance indicator to aid builders and designers in planning wall systems that maximize the thermal performance when considering all these variables.

Author Information

Pallin, Simon
Oak Ridge National Laboratory, Oak Ridge, TN, US
Boudreaux, Philip
Oak Ridge National Laboratory, Oak Ridge, TN, US
Gehl, Anthony
Oak Ridge National Laboratory, Oak Ridge, TN, US
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Developed by Committee: C16
Pages: 83–94
DOI: 10.1520/STP159920160099
ISBN-EB: 978-0-8031-7648-5
ISBN-13: 978-0-8031-7647-8