Exploring how the Passivhaus standard is increasingly being adopted to support the delivery of student accommodation projects

The Passivhaus standard adopts a whole-building approach to sustainability, with clear, measured targets focused on high-quality construction certified through an exacting quality assurance process.

And it is increasingly becoming adopted for schools and university buildings across the UK because of its reliable building performance, energy savings, and the benefits it can bring to occupant comfort and learning outcomes.

In recent years a number of student accommodation projects in the UK have been built to Passivhaus standards, including a 900-bed development for the University of the West of England (UWE).

Delivered by a project team which includes Stride Treglown, VINCI UK, and QODA Consulting; the £80m project is one of the largest low-carbon Passivhaus-certified developments of its kind in the world.

A spokesman for Stride Treglown said: “Applying the Passivhaus standard will radically reduce the buildings’ energy requirements, keep the indoor temperature comfortable all year round, and significantly reduce the running costs of the development.

Pushing boundaries

“The experience and expertise we have built up by delivering this project allows us to push the Passivhaus boundaries in certain aspects to maximise the quality of the architecture.

“We now know where we can push the boundaries and push the Passivhaus ‘golden rules’ to achieve a beautiful building that also performs its critical functions.”

Alex Bunn of QODA adds: “UWE’s net-zero carbon targets have driven this ground-breaking project, which puts sustainability and innovation at the heart of student accommodation design.

“By embracing demanding Passivhaus standards, and weaving energy efficiency principles into every facet of its design, UWE has demonstrated a steadfast commitment to a low-carbon future.

“This project sets an example for large-scale Passivhaus developments and stands poised to redefine the possibilities of campus living, offering a glimpse into a more-sustainable and comfortable future for students while reducing operating costs for the university.”

The accommodation has been designed to provide comfortable internal conditioning in both summer and winter and the university is predicted to achieve reduced costs of 40% and reduced emissions of 71% associated with space heating demand when compared with regulation student accommodation built to the current Building Regulations.

Energy demand

Another successful Passivhaus-certified student accommodation project is Lucy Cavendish College at the University of Cambridge.

Designed by R H Partnership Architects (rhp), the approach was taken to address in-use energy demand and to provide comfortable, well-ventilated spaces for students to live and study in.

Here we look more closely at the project, which completed in early 2023.

The brief

The college approach rhp with a pressing need to increase undergraduate residential accommodation within its grounds, requesting 72 ensuite student rooms with a café and social teaching space on the ground floor.

The new building also needed to link remodelled landscape spaces and circulation routes and integrate with the existing key facilities and residential buildings.

And the college wanted deliver as near as possible a zero-carbon development, leading to a design which achieves an innovative standard of sustainability beyond best practice.

 

Passivhaus

The project adopted Passivhaus as a way of targeting low operational energy and high occupant comfort.

In parallel with this, a sustainability matrix developed by Max Fordham, was used to help address wider sustainability, including water use, daylighting, and soft landings.

Embodied carbon is reduced by using a cross-laminated timber (CLT) structural frame, designed by structural engineers, Smith and Wallwork.

Considered a method of construction (MMC), the CLT is designed using standard-thickness panels sized for easy manufacture and transport, plus the timber panels themselves provide the airtightness line for an efficient modular construction.

And, in a first for both practices, the Passivhaus designer role was shared between rhp and Max Fordham up to planning to encourage collaborative design and this led to several other innovations which are now being adopted elsewhere, include bespoke details for the piled foundations and the use of glass-reinforced polymer (GRP) connections in the façade to minimise thermal bridging and improve overall U-values further contributing to Passivhaus performance.

The highly-insulated, very-airtight building reduces energy needs for heating or cooling, with openable windows providing summer comfort ventilation and it is designed to provide plenty of daylight in each room.

Solar shading also helps limit overheating, making the study bedrooms and kitchens comfortable spaces to use throughout the year.

The building is powered purely by electricity (no gas/fossil fuels) and air source heat pumps (ASHPs) provide both heating and hot water; a first for Cambridge college accommodation.

Other Passivhaus projects have typically used a mix of either ground source heat pumps or ASHPs with direct electric heating.

The design

The building is a part-three-storey, part-four-storey structure arranged in two connecting wings.

The ground floor comprises the cafe and study space to the west, close to the college dining hall, and has a lobby which provides an important circulation route through the building to the library.

rhp’s design strategy has been to break down the scale of the development into smaller units, closer in scale to the large Edwardian houses and other collegiate buildings in the neighbourhood.

By linking these smaller elements together with visual separating elements between units, a community of buildings, separate but interconnected, has been delivered.

Student wellbeing has also been considered from the outset and informed the proposed shapes, forms, and layouts of the rooms.

There is a range of bedroom layouts offering choice for students and all include ensuite shower rooms and are relatively square in shape so they can be accessed by wheelchair users.

Upper-level bedrooms have dormer windows and sloping roofs to provide a variety of spaces and accommodation is arranged so that all rooms have views to garden spaces and there a variety of types clustered around shared kitchen/dining/study spaces.

The window, furniture, and layout of the rooms have been designed through extensive engagement with college students, staff, and fellows and was carefully co-ordinated with the Passivhaus and accessibility requirements.

The design of the furniture was also considered at an early stage and rooms have been provided with small double beds and long workspaces adjacent to windows with integral window seats.

The shared kitchen spaces include facilities for cooking and dining as a group and the café, designed with Eve Waldron Design, provides space for students to study together and socialise, with a south-facing terrace overlooking the new library lawn and a new garden court to the north.

Materials

The building combines natural clay plain tiled roofs and facades with brickwork, zinc, and oak cladding to create a contemporary interpretation of the character of late Victorian villas and more-recent college buildings on site.

The steep pitch of the roof provides additional accommodation with dormer windows while eaves levels relate to neighbouring buildings. The gable ends and first floor of the West Wing feature handmade tile-hanging facades, picking up detailing on the existing buildings and breaking up the facades into a less-formal design. This helps to create a more-welcoming appearance for new students and relates to the character of buildings on site and in the local conservation area.

Tiled hoods projecting over south facing windows, and oak screening, provide solar shading while adding texture and rhythm to the façade.

Oak cladding and soffits surround the building’s entrances. These, combined with the texture of handmade tiling and varied Flemish bond brickwork, create a welcoming new heart for the growing college.

A spokesman for rhp said: “Passivhaus was the logical solution to addressing in-use energy demand, as well as providing comfortable, well-ventilated spaces for students to live and study.

“The design carefully balances low embodied carbon with robust long-life materials and offers a contemporary interpretation of the traditional forms and materials within the college site and surrounding West Cambridge Conservation Area.”