The Seed and Deptford Landings: Two Passivhaus projects from an MEP engineer’s perspective

Architect's render of Deptford Landings development, from the street.

At Max Fordham, we’ve delivered many exemplar Passivhaus projects in the UK: the first large-scale Passivhaus social housing project, the first net zero carbon private home, and the first Passivhaus Plus-certified school to be built using a traditional steel frame. We have a talented team of specialists who know to design innovative and industry-leading Passivhaus buildings that reduce operational energy and prioritise user comfort.

As an MEP engineer working on Passivhaus projects, I have had to develop an understanding of Passivhaus principles to deliver a design that can achieve Passivhaus certification at completion.

Two recent projects I’ve worked on have given me a greater insight into how Passivhaus principles are applied in practice. The first is a private house in Dundee called The Seed, and the second is Deptford Landings, a development of three blocks of flats in Lewisham for Peabody housing association, which is currently on site. 

These two projects had some similarities, but are also quite different in many aspects and required a different approach. Generally, designing blocks of flats for a developer can end up with a more efficient building, compared to a private client who might want energy-hungry features in their private home. However, the owners of The Seed were determined to achieve Passivhaus certification and were successful in their mission (they were even featured on the front cover of Passivhaus Plus magazine). They were able to do this despite a few challenging design features including two kitchens, and the non-form-friendly shape of the building, which has quite a lot of external facade. 

A cottage house surrounded by trees

The Seed, Dundee

A contractor team is also one of the other aspects that makes a significant difference to the delivery of a Passivhaus project. Peabody deals with large construction companies that are experienced with Passivhaus, but when working with the small Dundee-based contractor (for The Seed), we took a more active role in guiding them on some of the key principles such as micro-bore pipework for domestic hot water and for the MVHR to be near the external facade while minimising ventilation ductwork and pipe lengths as much as possible. 

Both projects used air source heat pumps (ASHP) for their heating demand and the heat emitters on both projects were radiators, Deptford was also able to satisfy comfort cooling using the ASHP on the roof, through the use of water source heat pumps (WSHP) inside each flat, which will provide coolth through a fan coil installed in the living room of each dwelling. ASHP distribution on reduced ambient temperature and a connection to a WSHP inside each dwelling (for heating, cooling and domestic hot water) has proven to be a popular solution for projects like Deptford, especially with the new Part O requirement for comfort cooling, as it allows the installation to utilise the same plant equipment for heating and cooling. 

At Deptford, we have included two large arrays of PV panels on the roof of two of the blocks, while the third block housed the ASHP plant. Unfortunately, the Seed is surrounded by trees, so we could not justify the installation of PV panels due to shadowing. The Seed was, however, very successful in using rainwater, both for outdoor shower facilities, watering the landscape and greenhouse plants, as well as the natural swimming pond in the middle of the grounds of the property. 

It has been great to work on both of these very different, but equally interesting projects. We’re proud to be at the forefront of Passivhaus design and as an MEP Engineer it’s exciting to see more people acknowledge Passivhaus as the future of sustainable building design.