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Investigation of the Impact of Commercial Building Envelope Airtightness on HVAC Energy Use.


pdf icon Investigation of the Impact of Commercial Building Envelope Airtightness on HVAC Energy Use. (994 K)
Emmerich, S. J.; McDowell, T.; Anis, W.

NISTIR 7238; 48 p. June 2005.

Sponsor:

Department of Energy, Washington, DC

Keywords:

heating; ventilation; air conditioning; commercial buildings; energy efficiency; infiltration; office buildings

Abstract:

This report presents a simulation study of the energy impact of improving envelope airtightness in U.S. commercial buildings. Despite common assumptions, measurements have shown that typical U.S. commercial buildings are not particularly airtight. Past simulation studies have shown that commercial building envelope leakage can result in significant heating and cooling loads. To evaluate the potential energy savings of an effective air barrier requirement, annual energy simulations were prepared for three nonresidential buildings (a two-story office building, a one-story retail building, and a four-story apartment building) in 5 U.S. cities. A coupled multizone airflow and building energy simulation tool was used to predict the energy use for the buildings at a target tightness level relative to a baseline level based on measurements in existing buildings. Based on assumed blended national average heating and cooling energy prices, predicted potential annual heating and cooling energy cost savings ranged from 3% to 36% with the smallest savings occurring in the cooling-dominated climates of Phoenix and Miami. In order to put these estimated energy savings in context, a cost effectiveness calculation was performed using the scalar ratio methodology employed by ASHRAE SSPC 90.1.