Hackbridge Primary School

Education

Hackbridge Primary School

The first UK Passivhaus Plus school

The Team

Client - London Borough of Sutton
Architect and Passivhaus Designer - Architype
Contractor - Lakehouse / Willmott Dixon
M&E engineer - Elementa
Photographer - Jack Hobhouse

Project Overview

Hackbridge Primary School is Passivhaus Plus‑certified. It is the first truly zero-carbon school in the UK, and incorporates a timber frame, cellulose insulation, PV panels and a ground-source heat pump.

WARM supported long-time partners in Passivhaus, Architype throughout the project, bringing significant experience of Passivhaus schools to help resolve several technically challenging aspects of the design and delivery.

The WARM difference

Supporting Certification

Meeting the Passivhaus Plus criterion required an ambitious Mechanical and Electrical system, including a ground-source heat pump. WARM assisted the design team in sourcing reliable performance data in the correct format for the PHPP modelling, ensuring that renewable energy contributions and system efficiencies were represented accurately and conservatively.

Bespoke Ventilation

WARM provided guidance on modelling the ventilation system, where units with unbalanced airflows and different heat recovery rates required bespoke calculations. This helped reduce the risk of performance gaps between design and operation.

Responsive Design Review

Review of site photography revealed a localised thickening of the external wall build‑up on one façade. WARM advised on how this change should be modelled and assessed the associated risk of condensation formation on embedded steel posts, allowing the team to address a potential long‑term durability issue before it became a problem.