Recommendations of the Scottish Passivhaus Equivalent working group

Scottish Passivhaus Equivalent logo

The Passivhaus Trust has been pleased to see the publication of the Scottish Government’s Energy Standards Review – Scottish Passivhaus Equivalent Working Group Consensus Report (November 2024). /

The report is a summary of recommendations from the two meetings of Working Group members held during the stage 1 consultation period, on 24 September and 8 October 2024. The Passivhaus Trust has been one of the members of the working group, represented by Jonathan Hines, Chair of Passivhaus Trust Scotland. The report represents the collective effort of the Working Group to find a consensus around the key elements required to make a Scottish Passivhaus equivalent deliverable.

The Passivhaus Trust is encouraged by the compromise position put forward by the working group, which aligns closely with its own recommendations. The Trust is waiting to see if the working group recommendations will be adopted by Scottish Building Standards for the implementation of the Scottish Passivhaus Equivalent policy.

It is really good news that absolute targets have been recommended for non-domestic buildings and that absolute targets are one of two possible compliance routes that have been put forward for domestic buildings. The recommendation on modelling tools to allow for PHPP as an alternative route is really positive. The unanimous support for Passivhaus as a means of compliance for building standards is also very encouraging.

Jon Bootland, Chief Executive, Passivhaus Trust

Summary of key recommendations

Timeline

Requirement for a clear timeline and route map with the provision of adequate time and resources for training to allow industry to upskill and reskill where required.

Tools

PHPP (Passivhaus Planning Package) to be accepted as an alternative for modelling and compliance.
The development of the Home Energy Model (HEM) and SBEM with a bespoke Scottish wrapper “with a similar accuracy as PHPP”

The Working Group notes: “modelling tools that produce sufficiently accurate results are essential. By sufficiently accurate we mean with similar outcomes to the Passivhaus Planning Package (PHPP) which neither the Standard Assessment Procedure (SAP) or the Simplified Building Energy Model (SBEM) currently achieve.”

Energy use intensity and unregulated energy

EUI should be one of the metrics included in the regulations
Unregulated energy should be included

Absolute Energy Targets

Adopted for non-domestic buildings,
Two alternative compliance routes for domestic buildings
- compliance with a new absolute target (which would include an allowance for renewables offsetting to allow sufficient flexibility)
- continued use of the notional building method.

Overall the Working Group supports the setting of absolute targets, rather than use notional building method. “There is an argument that the notional building method undermines the intention to design more efficient buildings. However, we recognise and acknowledge that the home building sectors are not ready to adopt this for numerous reasons, particularly the requirement to maintain flexibility with designs to satisfy compliance with building standards.” The report notes that the dual system route would enable the Scottish Building Standards Division to see how this develops and assess the impact / effectiveness of both absolute and notional.

Quality assurance

Rigour in quality assurance and compliance process at both design and construction stages should be strengthened to ensure that any potential performance gap is negated.

Deemed to satisfy

Unanimous support for the proposal for fully certified Passivhaus to be ‘deemed to satisfy’ building standards.

Embodied carbon

Whole life carbon should be included at the next update to building regulations and a route map to adoption should be developed.

Modern Methods of Construction

Address and encourage wide scale adoption of Modern Methods of Construction (MMC) as the regulations move to the Passivhaus Scottish equivalent standard.