Passivhaus Open Days keep their cool

Taking place during an intense June heatwave, with temperatures soaring above 30°C across much of the UK, the Passivhaus Open Days 2025 provided the perfect opportunity to experience the tangible benefits of Passivhaus living during hot weather.

Stretford EnerPHit. Image © Progress in Practice

From north to south, visitors across the tours remarked on how comfortably cool it felt indoors, in stark contrast to the sweltering heat outside.

The Passivhaus Standard places comfort at its core, incorporating a strict summer comfort criterion: internal temperatures must remain below 25°C for at least 90% of the year. This helps ensure year-round thermal comfort, warm and cozy in winter, comfortably cool in summer, without relying heavily on mechanical cooling.

From homeowners and architects to students and retrofit enthusiasts, attendees engaged with knowledgeable professionals to explore how Passivhaus design provides future-proofed, sustainable living. The Open Days reinforced the Standard’s reputation for delivering not only energy savings and carbon reductions, but also outstanding indoor comfort, regardless of the weather outside.

Participants visited 13 inspiring projects across the UK, at various stages of development. These included the 2025 Exemplar Sustainable Buildings Awards winner The Seed in Dundee, a riverside self-build on a constrained site in Worcestershire, and a 70-unit affordable housing development currently under construction in London.

UK Passivhaus Open Days 2025 Image © 1: John Street - Xin Jin LinkedIn, 2: The Seed - Chung Yan Chan LinkedIn, 3: Stretford EnerPHit - Tabitha Binding Linkedin 4: Anchorage Passivhaus – Tim Carter, 5: Parklands EnerPHit Plus – Donna Budden Eco Design Consultants

Retrofit also featured prominently this year, with numerous EnerPHit projects opening their doors, including a deep retrofit of Stretford EnerPHit near Manchester and a phased retrofit of Parklands EnerPHit Plus in the Midlands, demonstrating how Passivhaus principles can be successfully applied to the UK’s ageing housing stock.

Thanks to all participants

We’d like to thank everyone who generously opened their homes and buildings for the Passivhaus Open Days. Your knowledge and enthusiasm have made a lasting impression, helping to demonstrate, in real-world conditions, the exceptional quality, comfort, and resilience that Passivhaus buildings offer.

Can you open your doors?

Passivhaus site visits are a powerful way to share the lived experience of high-performance buildings. With public interest continuing to grow, we warmly invite you to take part in the Winter 2025 International Passivhaus Open Days, taking place from 7 – 9 November 2025. We look forward to seeing you there!