Class of 1986 Fitness and Wellness Center – Princeton University, Princeton, NJ, USA

During the renovation and expansion of Dillon Gymnasium into the Class of 1986 Fitness and Wellness Center, the goal was to transform a central recreational facility on Princeton University’s campus into a sustainable, forward-looking, and resilient hub of activity. This involved addressing topics such as reducing carbon emissions from construction and operations, stormwater management, user-centered and biophilic design, as well as social and economic sustainability.

The project team committed to an integrated planning process to achieve the sustainability goals. Stakeholders were involved from the very beginning of the project to ensure informed decision-making.

Early design workshops with stakeholders resulted in a project charter that defined the new fitness and wellness center as an inclusive, accessible, and flexible facility—highlighting Princeton’s commitment to sustainability. At the same time, it was equally important to specify that sustainability solutions must be cost-effective and provide both quantifiable and qualitative value. An essential outcome of the design process was the decision to renovate and expand the existing building rather than construct a larger new one, thereby reducing the building’s carbon footprint.

Two key design features of the fitness and wellness center exemplify Princeton’s sustainability philosophy: the green roof on the new addition and the mass timber construction. The green roof supports the campus-wide water management strategy and simultaneously reduces the building’s carbon footprint. Along with the exposed timber roof structure, the green roof serves as a tangible and visible symbol of Princeton’s commitment to sustainability and biophilic design.

The addition’s façade incorporates vertical fins on the east and west elevations, creating a strong architectural expression while providing effective solar shading. These are fixed but designed with a specific ratio to provide solar shading as a function of orientation. Additionally, the overhang facing south prevents direct sunlight while allowing ample natural daylight to enter the space without glare, ensuring the best possible visual connection between indoors and outdoors.

At the new addition, operable east- and west-facing windows and a rooftop exhaust fan are automatically activated, enabling ventilation by natural airflow when exterior conditions are favorable. Based on local climate conditions, fully natural ventilation may be feasible for up to 30% of the year.

Ceiling fans support air movement and are an integral part of the comfort strategy. By increasing air speed, they enhance perceived cooling in a highly energy efficient way, allowing comfortable conditions to be maintained even at higher temperatures and humidity levels. This approach enables higher indoor temperature setpoints during physical activity.

The fitness center is supplied by the campus's central district heating and cooling system, with energy recovery air handling units for conditioning.

Together, the minimized new construction, mass timber, green roof, and engineered natural ventilation and thermal comfort measures at the Class of 1986 Fitness and Wellness Center ensure comfortable building operation with reduced embodied and operational carbon emissions.