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Bristol Passivhaus Plus

Location: Nailsea, Bristol
Completion Status: Completed 2018 Occupancy: Occupied end of 2018
Architect: s2 Design Architects Consultant: Solarsense; Piers Sadler Consulting
Contractor: Greenheart Sustainable Construction Client: Private
Certification: September 2018 Certifier: WARM
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The number of certified schemes achieving the prestigious Passivhaus Plus seal is growing. The latest home to join the elite list is pioneering Bristol Passivhaus Plus, a collaboration between PHT members Greenheart Sustainable Construction, and Piers Sadler Consulting, along with s2 Architects

Bristol Passivhaus Plus, Certified, Nailsea

As its certification testifies this building works as a Passivhaus Powerhouse, designed to be largely self-sufficient in heating and hot water. The house is built on a flat plot in the clients’ large garden in Nailsea, west of Bristol, that used to be an urban infill site. It is tactfully located at the rear of the plot, facing south. To harness the benefits of this orientation, the roof is covered entirely in an integrated 7.3KW PV system. Part of the renewable source of heating and hot water is generated by the Mitsubishi Ecodan air source heat pump with thermal store, and the latest Powerwall 2 TESLA battery is used for storage. The clients are able to monitor the data via an app on a smartphone, laptop or tablet.

PAUL MVHR unit and TESLA battery


Predicted Energy Performance

 Airtightness n50 ACH@50pascals (≤0.6ach@50pascals) 

 0.35 ACH@50pascals

 Thermal Energy Demand (≤15kWh/m².yr)


 Thermal Energy Load (≤10W/m²)


 PER (Demand ≤45kWh/m2.yr) 

 (Generation ≥60kWh/m2.yr)

 Demand = 44kWh/m2.yr

 Generation = 70kWh/m2.yr

The structural timber frame was built on site from 360mm deep 'i' beams. The trussed roof has a shallow pitch and its simple form allowed the clients to save on costs and time.  

The external walls have been insulated with warmcel, clad in 80mm Pavatex and rendered in Baumit render. Pilkington solar control glass has been used to mitigate solar gain through the large sliding window. Passivhaus certified products were selected for all the windows and external doors, consisting of a combination of Rationel and Green Building Store, with Fakro for the triple glazed roof light.

The clients’ low carbon aspirations extend beyond just their home – having made provision for a car charging point, an electric car is next on the list…

Key Stats

  • Year of construction: 2018

  • Treated Floor Area:  153m²

  • Construction type: Structural Timber Frame 

  • Certification date: September 2018

Erecting the Structural timber frame
Bristol Passivhaus Plus solar roof

Key Team


Further information


Bristol Passivhaus Plus - Piers Sadler's presentation at the UK Passivhaus Conference 2018

Passivhaus Powerhouses


All images © Greenheart Sustainable Construction



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