Brennan Less

Brennan Less

Technology Researcher III
(510) 410-4036
eta.lbl.gov/people/Brennan-Less
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Bio

Brennan Lesshas spent nine years as a building science researcher at Lawrence Berkeley National Laboratory in the Residential Building Systems group and the Indoor Environment group. His current work focuses on state-of-the-art field measurements and simulations of smart ventilation systems, hygrothermal performance of sealed and insulated attics, indoor air quality, deep energy retrofits, zero net energy homes, and the health-energy efficiency nexus. He regularly presents his work at national conferences for the home performance and IAQ industries, and he is the author of over 20 research reports and technical journal articles. Brennan holds a Master of Science in Architecture degree from UC Berkeley – California (2012). He also has extensive experience as a home energy auditor and in residential construction and brings this hands-on approach to his research activities. 

Awards

HUD MBEST Tool Development -  May 25th 2023

A team of BTUS researchers created the Multifamily Building Efficiency Screening Tool (MBEST) for HUD's Green and Resilient Retrofit Program (GRRP) [https://www.hud.gov/grrp/leadingedge]. The GRRP covers grants and loans of almost $5 billion of investment in multifamily housing. The tool will be used to screen multifamily buildings and understand current opportunities for energy efficiency improvements.  The tool allows building managers and owners to enter information about lighting, HVAC heating/cooling systems, domestic hot water systems, and the building envelope to come up with a building score that allows HUD to make decisions about investing in building upgrades. The key reason for this SPOT nomination is that the LBNL team worked under considerable time pressure to create the tool in just a few weeks to meet HUDs deadline for launching the program and utilized their expertise and knowledge over a broad range of multifamily building performance to make the tool both comprehensive and easy to use. 

Spot: Brennan Less -  January 23rd 2020

Leading the Smart Ventilation for Advanced California Homes project to a successful conclusion.

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Societal Impact Award -  October 04th 2019

2019 Societal Impact

Citation: In recognition of the Residential Ventilation Team’s scientific research and development of technologies, practices, and standards for residential ventilation that have made millions of homes healthier and more comfortable.

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Publications

2023

Challenges and Opportunities for Home Decarbonization

Authors: Walker, Iain S.; Nuria Casquero-Modrego, and Brennan Less.
03/2023

2022

Getting to Scale for Decarbonizing Homes in the US: An Industry Survey

Authors: Casquero-Modrego, Nuria; WR Chan; Brennan Less, and Iain S. Walker.
11/2022

Compartmentalization and Ventilation System Impacts on Air and Contaminant Transport for a Multifamily Building

Authors: Walker, Iain S.; Brennan Less; David M. Lorenzetti; Michael D. Sohn, and Nuria Casquero-Modrego.
08/2022

Home Energy Upgrades as a Pathway to Home Decarbonization in the US: A Literature Review

Authors: Less, Brennan; Nuria Casquero-Modrego, and Iain S. Walker.
07/2022

Simulation-Based Analysis of Impacts of Reduced Envelope and Duct Air Leakage on Indoor Air Pollutant Concentrations in Occupied Manufactured Homes

Authors: Delp, William W.; Brennan Less; Haoran Zhao; Spencer M. Dutton; Wanyu R. Chan, and Brett C. Singer.
06/2022

The Costs of Home Decarbonization in the US

Authors: Walker, Iain S.; Brennan Less; Nuria Casquero-Modrego, and Leo I. Rainer.
06/2022

Pathways to Home Decarbonization

Authors: Walker, Iain S.; Brennan Less, and Nuria Casquero-Modrego.
06/2022

Analysis of Zoned Residential Ventilation Systems

Authors: Walker, Iain S.; Brennan Less; David M. Lorenzetti, and Michael D. Sohn.
05/2022

A Time-Varying Model for Predicting Formaldehyde Emission Rates in Homes

Authors: Zhao, Haoran; Iain S. Walker; Michael D. Sohn, and Brennan Less.
05/2022

Carbon and Energy Cost Impacts of Electrification of Space Heating with Heat Pumps in the US

Authors: Walker, Iain S.; Brennan Less, and Nuria Casquero-Modrego.
01/2022

2021

Development of Advanced Smart Ventilation Controls for Residential Applications

Authors: Walker, Iain S.; Brennan Less; David M. Lorenzetti, and Michael D. Sohn.
08/2021

Emerging Pathways to Upgrade the US Housing Stock: A Review of the Home Energy Upgrade Literature

Authors: Less, Brennan; Iain S. Walker, and Nuria Casquero-Modrego.
04/2021

DOE Deep Energy Retrofit Cost Survey

Authors: Chan, Wanyu R.; Brennan Less, and Iain S. Walker.
01/2021

The Cost of Decarbonization and Energy Upgrade Retrofits for US Homes

Authors: Less, Brennan; Iain S. Walker; Nuria Casquero-Modrego, and Leo I. Rainer.

2020

Smart Ventilation for Advanced California Homes

Authors: Less, Brennan; Iain S. Walker; David M. Lorenzetti; Evan Mills; Vi H. Rapp; Spencer M. Dutton; Michael D. Sohn; Xiwang Li; Jordan D. Clark, and Max H. Sherman.
06/2020

Measured Moisture Performance of Sealed and Insulated Attics with Permeable Insulation In California Homes

Authors: Walker, Iain S., and Brennan Less.

Assessment of peak power demand reduction available via modulation of building ventilation systems

Authors: Young, Matthew; Brennan Less; Spencer M. Dutton; Iain S. Walker; Max H. Sherman, and Jordan D. Clark.

2019

Sealed and Insulated Attic Hygrothermal Performance in New California Homes Using Vapor and Air Permeable Insulation—Field Study and Simulations

Authors: Less, Brennan; Iain S. Walker; Jonathan L. Slack; Leo I. Rainer, and Ronnen M. Levinson.
04/2019

Energy savings with outdoor temperature-based smart ventilation control strategies in advanced California homes

Authors: Less, Brennan; Spencer M. Dutton; Iain S. Walker; Max H. Sherman, and Jordan D. Clark.
04/2019

Efficacy of occupancy-based smart ventilation control strategies in energy-efficient homes in the United States

Authors: Clark, Jordan D.; Brennan Less; Spencer M. Dutton; Iain S. Walker, and Max H. Sherman.
03/2019

Ventilation and Indoor Air Quality in New California Homes with Gas Appliances and Mechanical Ventilation

Authors: Chan, Wanyu R.; Yang-Seon Kim; Brennan Less; Brett C. Singer, and Iain S. Walker.

Smart Ventilation for Advance California Homes – Single Zone Technology Task

Authors: Less, Brennan; Spencer M. Dutton; Xiwang Li; Jordan D. Clark; Iain S. Walker, and Max H. Sherman.

2018

Rethinking Occupancy-Based Ventilation Controls

Authors: Walker, Iain S., and Brennan Less.

Energy Savings Estimates for Occupancy- and Temperature-based Smart Ventilation Control Approaches in Single-family California Homes

Authors: Clark, Jordan D.; Iain S. Walker; Brennan Less; Spencer M. Dutton; Xiwang Li, and Max Sherman.

Energy Savings Estimates for Occupancy and Temperature-based Smart Ventilation Control Approaches in Single-family Homes

Authors: Clark, Jordan D.; Iain S. Walker; Brennan Less; Spencer M. Dutton; Xiwang Li, and Max H. Sherman.

2017

Smart Ventilation Controls for Occupancy and Auxiliary Fan Use Across U.S. Climates

Authors: Less, Brennan, and Iain S. Walker.

2016

A Literature Review of Sealed and Insulated Attics—Thermal, Moisture and Energy Performance

Authors: Less, Brennan; Iain S. Walker, and Ronnen M. Levinson.

Development of Smart Ventilation Control Algorithms for Humidity Control in High-Performance Homes in Humid U.S. Climates

Authors: Less, Brennan; Iain S. Walker, and Sara Ticci.

Smart Ventilation Control of Indoor Humidity in High Performance Homes in Humid U.S. Climates

Authors: Less, Brennan, and Iain S. Walker.

A Field Study of Wall Furnace Venting and Coincident Exhaust Fan Usage in 16 Northern CA Apartments

Authors: Singer, Brett C.; Brennan Less; William W. Delp; Andrew D Brooks; Sebastian Cohn, and Brian Finn.

2015

Assessment of Literature Related to Combustion Appliance Venting Systems

Authors: Rapp, Vi H.; Brett C. Singer; J. Chris Stratton; Craig P. Wray, and Brennan Less.
06/2012

Results of the California Healthy Homes Indoor Air Quality Study of 2011-2013: Impact of Natural Gas Appliances on Air Pollutant Concentrations

Authors: Mullen, Nasim A.; Jina Li; Marion L. Russell; Michael Spears; Brennan Less, and Brett C. Singer.
03/2015

Deep Energy Retrofit Guidance for the Building America Solutions Center

Authors: Less, Brennan, and Iain S. Walker.
01/2015

Indoor Air Quality in 24 California Residences Designed as High-Performance Homes

Authors: Less, Brennan; Nasim A. Mullen; Brett C. Singer, and Iain S. Walker.

2014

A Meta-Analysis of Single-Family Deep Energy Retrofit Performance in the U.S.

Authors: Less, Brennan, and Iain S. Walker.

Houses are Dumb without Smart Ventilation

Authors: Walker, Iain S.; Max H. Sherman, and Brennan Less.

An Assessment of Envelope Measures in Mild Climate Deep Energy Retrofits

Authors: Walker, Iain S., and Brennan Less.

Deep Energy Retrofit Performance Metric Comparison: Eight California Case Studies

Authors: Walker, Iain S.; Brennan Less, and Jeremy Fisher.

Indoor Air Quality and Ventilation in Residential Deep Energy Retrofits

Authors: Less, Brennan, and Iain S. Walker.

Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

Authors: Less, Brennan; Iain S. Walker, and Yihuan Tang.

2012

Deep Energy Retrofits—Eleven California Case Studies

Authors: Less, Brennan; Jeremy Fisher, and Iain S. Walker.
10/2012