Passivhaus Affiliate

Sciennes Primary School scores full marks!

Sciennes Primary School pupils will start the new term in style with the completion of their new, four classroom Passivhaus extension, designed to meet modern educational needs.  Nestled in PHT Patron City of Edinburgh Council's historic Marchmont area, the project prioritises a fabric-first approach, with meticulous attention to air tightness and thermal performance.

Sciennes Primarty School extension | Image credit: Holmes Miller


The proposed pavilion complements the existing primary school with a simple and refined architectural design.  Due to the multiple site constraints, PHT Member Holmes Miller's design utilises abundant windows on just two facades, complimented with strategic roof lights, to infuse the space with natural light and optimise the learning environment.


QUOTE: The new classroom block will be the first primary school building in the Capital to be certified to Passivhaus Standard and supports our aim of net zero emissions by 2030 |  Cllr Ian Perry, Education Convener, City of Edinburgh Council


Key stats:

  • Construction: Stone-clad cross laminated timber (CLT) 
  • Project value: £3.2million
  • Completed: August 2023
  • Certified: Aiming for certification
Sciennes Primary School | Image credit: Maxi Construction


Sciennes Primary School extension. Image credit: Holmes Miller
Sciennes Primary School | Image credit: Indeglas Sciennes Primary School | Image credit: Maxi Construction Sciennes Primary School | Image credit: Indeglas



The classrooms are built using stone-clad, explosed cross-laminate timber (CLT) frame to all visible elevations with brick for secondary walls, all surrounded by enhanced playground space.

Sciennes Primary School | Image credit: Maxi Construction


The structural design not only ensures thermal comfort by minimising cold bridging but also contributes to carbon storage and environmental preservation, with every cubic meter of CLT sequestering one tonne of CO2. Furthermore, this material's recyclability and biodegradability underline a dedication to eco-conscious practices.


Sciennes Primary School | Image credit: WARM


Building performance

Sciennes Primary School | Image credit: Maxi Construction


Aiming for an impressive air tightness performance of 0.3 ACH @ 50 Pa the building envelope was designed to minimise openings and perforations.  The addition of triple glazing and well-insulated walls and roof allowed the air tightness target to be achieved, with final air test results of 0.17 ACH occupied conditions (MVHR systems operating) & 0.28 ACH night-time conditions (MHVR systems off)








Designed energy performance

Airtightness n50 (≤ 0.6ACH @ 50 Pa)                           


0.3 @ 50 Pa


Space Heating Demand (≤ 15 kWh/m².a)


15.5 kWh/m².a  


Heating Load (≤ 10 W/m²)


9.0 W/m²




Due to the robust project brief and design, the main challenges on this project occurred from the extension’s location. The narrow boundary spaces lead to discussions around space for access equipment to maintain the building as well as how to deal with limited opportuniites for daylighting strategy.


Key team:

  • Client: PHT Patron City of Edinburgh Council
  • Architect: PHT Member Holmes Miller
  • Passivhaus Consultant: Sussed Sustainability  
  • Project Managers: Doig & Smith        
  • Contractor: Maxi Construction
  • Engineer:  PHT Member Will Rudd 
  • Passivhaus Certifier: PHT Patron WARM
Sciennes Primary School | Image credit: Maxi Construction


Join us

UK Passivhaus Conference 2023 | 16-17 October | in-person in Edinburgh and online

Discover further educational case studies adopting Passivhaus in our educational buildings campaign or join us as we showcase pioneering Scottish schools on day one of the 2023 UK Passivhaus Conference in Edinburgh. Be sure to register early for the site visits!

On the 16th and 17th October, we will be exploring the adaptability of Passivhaus, its implementation and benefits over a diverse range and scale of projects around the UK, and its potential applicability throughout Scotland! Be sure to register early for the site visits! 



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Further information

Sciennes Primary School - Holmes Miller

UK Passivhaus Conference 2023

Passivhaus for Educational Buildings

Passivhaus & Planning

Passivhaus Benefits Guide & costs research

Scottish equivalent to Passivhaus: FAQs

Joined-up approach can help construction industry achieve green goals - Project Scotland

Maxi awarded Passivhaus Extension to Sciennes Primary Schoo - Maxi Construction

14th August 2023

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