About Us


Sweek Consulting Engineers, LLC is a Seattle-based consulting firm specializing in energy efficiency engineering consulting services within the construction industry. We provide targeted, technical support for existing buildings, new construction projects, and firms seeking to enhance in-house technical expertise. We have 19 years’ experience with the commissioning process and the LEED™ green building rating systems.



Treasa Sweek (PE) - Principal

Treasa Sweek is an experienced project manager and registered mechanical engineer who focuses on existing building commissioning, measurement and verification services for new construction, performance audits, energy policy, and evaluating utility EE programs. Her goal is to guide teams working to optimize the efficiency of the design and operation of building systems. Treasa has been a certified commissioning provider since 2004 and has led the new construction commissioning process on over 2.5 million square feet (25+ buildings). She has served as the commissioning representative on the Washington State Energy Technical Advisory Group since 2009. In that role, Treasa authored and passed commercial code change proposals (2012, 2015), and led a coalition of commissioning professionals to re‐write chapter C408 of the energy code (2017-8).


Sarah Starkweather (MCRP, PhD) - Administrator and LEED Reviewer

Sarah Starkweather lends her eye for detail to Sweek's day-to-day business activities, managing our business development, marketing, and overall business administration. Sarah has helped Sweek build a successful line of business performing highly detailed, focused quality assurance reviews for the Green Business Certification, Inc., the certifiers of the WELL Building and LEED Green Building rating systems.



Our Project Partners


Sheila Roe

Sheila Roe is a building systems testing technician. She earned her Sustainable Building Science Technology degree at South Seattle College in 2021. Sheila supports the commissioning process including preparing customized functional test forms and field testing apartments in new buildings. She also supports the NW chapter of the Building Commissioning Association with "back stage" office administration.



Steve Abercrombie
Connected Buildings

Steve Abercrombie supports Sweek Engineers on limited engagements applying his background at the intersection of education, sustainable building, and information technology. Steve and Treasa have collaborated on commissioning projects for 10 years. Steve's goal is to use technology to streamline construction quality assurance / quality control. Steve has been a certified commissioning provider since 2018.



Duane and Carol Lewellen
Lewellen Associates

Duane Lewellen has spent all of his adult life in the world of energy efficiency. He holds an ATA in Energy Management from Edmonds Community College and a BS in Business from City University. He has applied his knowledge at PUD, Rice Group, Inc., NEEC, BOC Certification as lead Instructor, Smart Buildings Center, Lewellen Associates, LLC, Seattle City Light, and the WSEC TAG. Duane is a CEM, LEED AP, Past President of the PNWC of AEE, a recipient of the AEE Energy Manager of the Year for 2013.


Carol Lewellen is considered the godmother of residential energy conservation as she was the first energy auditor hired by Seattle City Light Conservation Program in 1978. Carol has worked at SCL, SNOPUD, Edmonds Community College, and NEEC.


Erin Connor

Keel Energy

Erin works as an energy efficiency consultant specializing in technical and diagnostic services, providing consultation, commercial air barrier testing and HVAC commissioning for code compliance and above code program certification. Erin is passionate about improving building efficiency and has worked on multiple national research studies related to the built environment and new energy efficient technologies.