Scotland plans to add PassivHaus to Building Regs

The Scottish Government has outlined plans to update Technical Handbook Section 6 to scrap SAP and further tighten fabric performance standards. They're calling it a 'PassivHaus equivalent standard'.

Specific details and timeframes will be confirmed later this year, with the final ‘Go Live’ date already confirmed as 31st March 2028.

You can read the full article here:

https://www.gov.scot/publications/scottish-building-regulations-proposed-changes-energy-environmental-standards-determining-principles-scottish-equivalent-passivhaus-standard-scottish-government-stage-1-consultation-response-part-2-onward-review/

Scotland leads the rest of the UK in terms of setting fabric standards and energy performance targets for housebuilders.

The plan so far is:

🟢 In line with England & Wales, SAP will be retired as the approved assessment tool. It will be replaced by the new Home Energy Model.

But unlike in England & Wales, Scotland also wants to allow PHPP as an alternative route to compliance. PHPP is the calculation method used for PassivHaus assessments.

We don’t have specifics about targets or what compliance looks like, so we don’t yet know exactly how PassivHausy this commitment truly is.

🟡 For compliance targets in Scotland, they want to keep the current Delivered Energy Rate as the main metric (bearing in mind the more familiar Target Emission Rate is now obsolete in Scotland).

🟠 The Notional Recipe (that calculates the TDER) could be replaced with an 'absolute' figure. In other words, a single number that's the same for every dwelling. That's still up for discussion.

🟣 A new, second target has been proposed – the Space Heating Rate. This will focus on fabric performance and heating efficiency. To keep us assessors on our toes, it's calculated differently to the Energy Use Intensity metric that’s been proposed in Wales.

Some other noteworthy points:

- In the current Technical Handbooks, there’s no maximum air test target, so that’s going to be rectified. The target in England and Wales is 8.

- There was talk of mandating MVHR ventilation, as that would pair nicely with a PassivHaus equivalent standard. But that's no longer being proposed. Any ventilation system will be allowed as long as the dwelling meets compliance with the relevant air flow rates and energy targets.

- Also, the overheating requirements in Section 3 are going to be reviewed – expect more info about that later in the year.

We should receive definitive news about the revised text of Handbook Section 6 and the details of the HEM Scotland wrapper later this year. Watch this space!