Investigation of the Impact of Commercial Building Envelope Airtightness on HVAC Energy Use.
Investigation of the Impact of Commercial Building
Envelope Airtightness on HVAC Energy Use.
Emmerich, S. J.; McDowell, T.; Anis, W.
NISTIR 7238; 48 p. June 2005.
Sponsor:Department of Energy, Washington, DC
heating; ventilation; air conditioning; commercial
buildings; energy efficiency; infiltration; office
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.