Sustainable Preservation: Balancing Sustainability & Historic Integrity

By Kelly Newton, Summer Intern

Point of View
Anderson Hall at University of Washington (Photo Credit: Cochran, Inc.)

Kelly Newton joined the Portland studio as a summer historic preservation intern, participating in the firm’s robust internship program that includes conducting an in-depth research project. Kelly is currently pursuing a Bachelor of Interior Architecture at the University of Oregon, with a minor in Historic Preservation. Read more from our 2026 internship cohort and all our past intern research projects here.

Historic Buildings: The Future of Sustainability

Sustainability in new building design is a fast-evolving topic and goal in the architecture industry. Although many strategies currently exist and are being explored for new builds, a lesser-known topic is how sustainable measures can be implemented in existing buildings – specifically, historic ones. Implementing sustainable strategies in historic buildings can seem challenging, requiring more thought and creativity when trying to seamlessly integrate modern technologies with historically significant fabric. However, historic buildings are the best avenue for achieving a sustainable future, while also preserving history and cultural heritage for future generations. Sustainable preservation approaches are possible in the categories of carbon and energy modeling; building envelope; and mechanical, electrical, and plumbing (MEP) systems and can be fine-tuned by using a range of tools.

Carbon and Energy Tools

The embodied carbon in existing buildings makes them a prime target for the future of reducing the carbon footprint of the built environment. The Association for Preservation Technology, in a recent journal publication, identified several modeling tools used throughout different stages of the design process that can help understand, evaluate, and record carbon and energy impacts in a preservation project.

Tools like C.Scale and the Carbon Avoided: Retrofit Estimator (CARE) Tool can be utilized early in the design process to give a better understanding of carbon impacts. The CARE Tool specifically is geared toward projects with a renovation aspect to them, enabling users to estimate the amount of carbon avoided by reusing an existing building rather than constructing a new one. This helps in advocating for building reuse, rather than demolishing and building new.

Tools like energy modeling programs, Tally, EC3, THERM, and WUFI can be implemented in the phases of schematic design and design development. They enable users to evaluate carbon tradeoffs and energy performance, allowing them to make decisions on material retention and targeted repair strategies.

Lastly, there are tools that can be implemented later in a project, during the construction documents phase. Tools like EC3 and blower door testing record and validate embodied and operational carbon reductions. EC3 tracks and reports embodied carbon from materials, and blower door testing evaluates airtightness, which is critical for energy performance. While they are helpful for recording and documenting the effectiveness of sustainable strategies that were implemented, they are less impactful in their ability to reduce carbon, unlike the benchmark and optimization tools that are implemented earlier and affect design direction.

Sample information generated from the CARE Tool (Architecture 2030). Source: User Guide | CARE Tool

Building Envelope

The envelope of a building is an important target in terms of sustainable preservation strategies. When trying to preserve historic character, it can be a challenge balancing the need to preserve character-defining features and to implement energy efficiency.

The first goal when examining a historic building envelope is to leverage the existing inherent sustainable features it may have to offer. These are characteristics of a building or site that, through their design, physical materials, or natural systems, embody principles of sustainability. Some examples are thick masonry walls, deep-set windows, operable windows, skylights, porches, and many more. Identifying these features and restoring them to their full potential is a simple strategy for implementing sustainability in a way that already seamlessly flows with the building character.

Looking at windows specifically, they are a hot topic when it comes to building envelope performance in historic buildings. If following the Secretary of the Interior’s Standards for Rehabilitation, the principle is always repair rather than replace. If that is not feasible, then replacing in-kind is the next approach. Many historic buildings have single-pane windows, but these don’t necessarily need to be replaced to increase energy efficiency. Solutions for this include applied thermal films, Slim Line Insulating Panes (SLIP), operable storm windows, and interior storm windows. SLIP panels specifically can be installed over existing glazing, enhancing thermal performance without altering original sash profiles, materials, or sightlines. Because original windows can be an important character-defining feature of historic buildings, it is vital to try and preserve and restore them, while also adding energy efficiency if possible.

historic courtroom interior
The historic laylight in the Oregon Supreme Court building is an inherently sustainable feature.

Mechanical, Electrical, and Plumbing

Strategic MEP decisions help target operational carbon in a building. Some sustainable options that can be applied to historic buildings are air-source heat pumps, variable refrigerant flow (VRF) systems, ground-source (geothermal) heat pumps, energy recovery ventilators, heat pump water heaters, and many more. VRF systems are beneficial because they require less ductwork than traditional HVAC systems, making it easier to seamlessly integrate into historic building fabric. Renewable energy, like photovoltaic or solar panels, can also be integrated, but only in a way that doesn’t adversely affect the historic look of the building.

Anderson Hall at University of Washington (Photo Credit: Cochran, Inc.)

Case Study: University of Washington Anderson Hall Renovation

At University of Washington’s Anderson Hall, Hennebery Eddy designed an historic renovation with targeted sustainable preservation interventions throughout the building, balancing increased efficiency with retention of historic integrity.

  • For early-on sustainable preservation approaches, the team used energy modeling, preservation zoning, and embodied carbon tracking to identify where interventions could be made without adversely affecting the historic character of the building.
  • For the envelope, the team used the established preservation zones to identify where adding insulation would be feasible – both for the impact to character-defining features and to see where added insulation would actually increase energy performance.
  • As far as MEP systems, strategies such as the use of water source heat pumps, a dedicated outdoor air system (DOAS), fan coil units with hydronic heating and cooling coils, energy consumption metering, and LED lighting were implemented. All of these interventions led to the proposed design achieving 28% energy cost savings against the LEED baseline.

As a result, the UW Anderson Hall project team was able to honor and preserve the history of this Seattle Historic Landmark, while implementing sustainable strategies and designing for future use, thus allowing the building’s story to be told for generations to come.

Diagram showing uninsulated historic walls in red and insulated walls in blue at UW Anderson Hall.

Internship Experience

My time at Hennebery Eddy this summer has been such a great learning experience. I was able to delve into the everyday tasks of historic preservation and get hands-on experience working with amazing professionals. From learning the process of wood identification and paint analysis to technical writing and research, I gained a broad understanding of the different aspects of preservation services. I loved that I could combine my interest in preservation with my love for design in a meaningful way. I will certainly take all I have learned this summer with me as a complete my last year of school and prepare for my future career!

Research Sources