Passive Design Case Studies
The Carbon Issue

At KPF we believe that good buildings take care of their occupants; they are beautiful, comfortable, and resilient spaces in which to live, work, and play. This means careful consideration not only of how a building looks, but also how it responds to its environment. A well-designed, climate-responsive building is sited in such a way that it takes advantage of the local microclimate, cools itself in hot temperatures, keeps inhabitants warm during cold weather, shields its users from glare, and can maintain a certain level of thermal comfort without mechanical systems in the event of power failure.

Note:

This article originally appeared in the spring 2024 issue of KPF Review. View all of the accompanying videos here.

These aspects of a building’s performance rely on passive measures instead of mechanical systems; they are purely a matter of design. Passive design strategies have an obvious environmental benefit and can reduce the need for energy-intensive heating, cooling, ventilation, and lighting, drastically cutting a building’s carbon footprint.

On the path to net-zero carbon emissions, they play an especially critical role, reducing not only overall energy demand, but also peak thermal demands during the hottest and coldest times of the year. This reduction allows the design to take advantage of low-carbon, cutting-edge mechanical systems such as radiant cooling, heat pump–based electric heating, and heat storage.

In the context of climate change and extreme weather events, the long-term performance of buildings depends on their ability to adapt to changing conditions. Well-insulated buildings that take advantage of passive thermal regulation can help provide flexibility and security for building occupants even in case of extreme heat or power failure.

The three projects that follow—Bard College Residence Halls, Channelside, and 105 Victoria Street—are good buildings. Well-sited, comfortable, efficient, and beautiful, they demonstrate not only KPF’s work at the cutting edge of energy efficiency, but also our sustained commitment to creating robust building solutions that are responsive to their contexts.

Channelside’s waterfront promenade. Credit: dbox.

Bard College Residence Halls

Annandale-on-Hudson, NY, USA

Play

When complete, KPF’s residence halls for Bard College in upstate New York will house over 400 students across four new dormitory buildings and will feature an additional communal building to serve as a gathering and amenity space for students. A key goal for the client was to achieve Passive House certification, one of the most stringent standards for a building’s energy efficiency.

Passive House structures are super-insulated and able to maintain a comfortable interior temperature using very little energy. The drastically reduced operational carbon footprint of a Passive House scheme, combined with heating and cooling provided by a geothermal field will help the college achieve its goal of decarbonizing its campus.

Credit: RGB.

Though these types of buildings are efficient, they are not always thought of as being expressive, as they must prioritize a tight building envelope over dramatic gestures. In this project, KPF challenges that stereotype, creating moments of articulation and artful materiality within the project’s relatively straightforward geometry.

Recessed, super-insulated windows add a sense of depth to façades and minimize thermal loss, while the buildings’ brick cladding itself becomes a canvas for expression. KPF designers created texture on the surface of each building by pulling bricks out from the wall plane and pushing them in to create contrast around windows and entrances. The result is a dynamic accent created from a material better known for its solidity.

Robust insulation ensures residents’ comfort with minimal heating and cooling.

Channelside

Boston, MA, USA

Channelside, a 6.5-acre waterfront development in Boston, heals a decades-old tear in the city’s urban fabric and transforms what was once a flood-prone parking lot into a vibrant mixed-use community of laboratories, offices, retail experiences, and residences, including affordable and artist-dedicated units.

The three buildings that make up Channelside include a laboratory (LEED Platinum), an office building (LEED Gold), and residential building (LEED Gold), and are designed to reduce energy usage by 24–47% compared to 2020 code. KPF’s design lifted the development onto a berm, which gently rises to 6 feet above grade, protecting the site from floods and establishing new connections to the harbor.

The buildings feature a triple-layered curtain wall system—in which triple-paned IGUs are punctuated by brick and pre-cast concrete panels—that performs 10% better than Boston energy code. The staggered design integrates sunshades and conceals the scale of insulated aluminum piers and spandrels, which reduce the window-wall ratio, helping it achieve a more efficient thermal envelope.

The residential tower. Credit: dbox.

Windows across the Channelside development were optimized based on façade angle and building program to provide sweeping water views while limiting heat loss and solar glare. The residential and lab buildings, for example, have a lower window-to-wall ratio than the office tower.

Though Channelside will be home to researchers working at the cutting edge of scientific innovation, its scale and material palette of brick and metal is designed to blend harmoniously with the timeless character of nearby historic loft structures such as the Boston Wharf Company building.

105 Victoria Street

London, UK

Conceived of as a new destination for London’s West End, 105 Victoria Street is a mixed-use development that employs multiple innovative strategies to reduce whole life carbon. In this project, particular emphasis was paid to the façade as a zone of interaction between outdoor and indoor environments that could be harnessed for interior cooling and ventilation.

The entry to 105 Victoria Street. Credit: dbox.

The project’s façade is informed by its urban context; neighboring buildings shade the east and west of the structure, but to the south it is more exposed. KPF adopted passive design principles for the façade to manage solar gain and reduce embodied carbon while optimizing daylight access for occupants. Detailed thermal modelling was used to determine the ratio of solid wall to vision areas of each side, while projecting elements were optimized to reduce material use while maximizing shade.

KPF designed the façade of 105 Victoria Street in London to accommodate mixed-mode ventilation and free cooling. Heat recovery units recycle exhaust heat, reducing energy use.

A high-performance system of louvers and vents incorporated into the façade units allows for mixed-mode ventilation and free cooling. On every floor, plug and play modules above the windows for mechanical ventilation intake and exhaust are designed to be interchangeable, offering tenants maximum space-planning flexibility. Occupants also benefit from parallel opening vents for natural ventilation along the perimeter zone, which can be employed in the building’s nighttime cooling strategy.