ASHRAE Journal - October 2024 - 17

COLUMN RESIDENTIAL APPLICATIONS
process, based on user inputs of the existing wall and
user-selected retrofi t BSA recommendations.
¥ The improvement in the thermal performance
of the wall assembly is also given. The R-value of the
wall increased from 3.2 ft2·°F·h/Btu· to 17.9 ft2·°F·h/Btu
(0.56 K·m2/W to 3.16 K·m2/W).
The moisture durability gauges indicate the existing
and retrofi tted wall systems durability indices for mold
and sheathing moisture content risk did not increase.
Use Cases for BSA
BSA is designed for users who have some familiarity
with how building envelopes are constructed. It can be
used by building science students and builders, building
inspectors, energy raters/auditors, manufacturers,
architects and engineers. It is not intended to replace
more sophisticated hygrothermal moisture models that
are available. The existing database is comprised of wall
assemblies typical of today's construction practices and
does not contain simulation data on systems that have
small market share or are in development.
The BSA can also be used as an informative educational
tool to accelerate workforce training on building
science and moisture durability by providing a more
intuitive way to learn building science. Impacts on the
moisture durability of a wall system can be quickly
tested using the BSA. Questions like what class of vapor
retarder should be used, what happens if I switch
from a brick cladding to a vinyl cladding (absorptive
vs. nonabsorptive cladding) or should a permeable
vs. an impermeable water resistive barrier be used
can be answered quickly and their consequences
can be immediately displayed. BSA has a signifi cant
amount of information in the " help " screens that can
assist a student in further understanding the nuances
of moisture transport in building envelopes with
numerous references for more detailed information.
BSA is also linked to DOE's Building America Solution
Center (BASC) " resource library " of best practices in
residential building science (https://basc.pnnl.gov).6
Applying BASC best practices such as " build tight and
ventilate right " and proper HVAC practices are critical to
moisture management in new and retrofi tted homes.
Another possible use of the BSA would be workforce
training associated with the Infl ation Reduction
Act's energy effi ciency residential tax credits for new
construction (45L) 7 and existing homes (25C).8
If designing a traditional assembly, architects and
consultants can evaluate the durability of their design
without the need for acquiring and learning how to use
a complex hygrothermal model. Building designers can
also use BSA to quickly assess the implications of their
design or design changes. Material substitution issues
can be resolved quickly without the need for waiting on
a consultant to evaluate the proposed modifi cations.
In conclusion, BSA supplies unbiased data and
recommendations that assist in understanding moisture
durability when constructing or retrofi tting existing
residential walls. Hopefully this tool will increase the
confi dence of those responsible for building envelope
design, help educate the next generation of building
scientists and demonstrate that energy effi ciency and
durability are not mutually exclusive.
Currently, BSA supports guidance on typical
residential wall assemblies. BSA is continuously
improving with plans to expand the database to cover
attics and nonstandard wall assemblies in the future.
Acknowledgments
This manuscript has been authored in part by
UT-Battelle, LLC, under contract DE-AC05-00OR22725
with the U.S. DOE. The publisher acknowledges the
U.S. government license to provide public access
under the DOE Public Access Plan (https://tinyurl.com/
bddzttap). A special thank you to Eric Werling at the U.S.
DOE Building Technologies Offi ce for his leadership
and vision in support of residential building science
research, development and deployment.
References
1. DOE. 2014. " Windows and Building Envelope Research and
Development: Roadmap. for Emerging Technologies. " U.S.
Department of Energy. https://tinyurl.com/yc52wjyj
2. ORNL. 2024. " Building Science Advisor. " Oak Ridge National
Laboratory. https://bsa.ornl.gov
3. Salonvaara, M., A. Desjarlais, A. Aldykiewicz Jr., E. Iffa, et
al. 2023. " Application of Machine Learning to Assist a Moisture
Durability Tool. " Energies 16(4).
4. ANSI/ASHRAE Standard 160-2016, Criteria for Moisture-Control
Design Analysis in Buildings.
5. ICC. 2018. " International Energy Conservation Code. "
International Code Council.
6. PNNL. 2024. " Building America Solution Center. " Pacifi c
Northwest National Laboratory. https://basc.pnnl.gov
7. DOE. 2023. " Section 45L Tax Credits for Zero Energy Ready
Homes. " U.S. Department of Energy. https://tinyurl.com/yezxyah8
8. DOE. 2023. " How to Ensure Your Home Energy Audit Qualifi es
for a $150 Tax Credit. " U.S. DOE. https://tinyurl.com/2s39n6nt
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https://tinyurl.com/bddzttap https://tinyurl.com/bddzttap https://tinyurl.com/yc52wjyj https://bsa.ornl.gov https://basc.pnnl.gov https://basc.pnnl.gov https://tinyurl.com/yezxyah8 https://tinyurl.com/2s39n6nt http://www.ashrae.org
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