Scottish passive house equivalence receives cautious welcome

The Trust, which broadly welcomed the direction of the proposals, singled out four developments in particular: the recognition of Passivhaus certification as a "deemed to satisfy" route to compliance with Scottish building standards; a stronger emphasis on measured building performance through absolute energy targets, including space heating and delivered energy metrics; formal recognition of PHPP as a compliance tool; and improved compliance and assurance mechanisms via a proposed handbook.

Chief executive Jon Bootland called the "deemed to satisfy" decision a step of global significance, and said he hoped Scotland can implement it swiftly, with the rest of the UK following suit.

At the same time, the Trust identifies five areas for improvement. It wants ventilation losses folded into the space heating metric, arguing the figure is otherwise unrepresentative of real-world performance and pushing for tighter airtightness targets, calling the proposed 5 m³/(h.m²) ceiling an improvement but still too loose.

The Trust also raised concerns about solar PV requirements, which it says currently make the jump from "good" to "best practice" fabric standards disproportionately expensive. Rather than a range of space heating targets, the Trust advocates for a single metric, pointing to the London Plan's baseline-plus-aspirational approach as a possible model. Finally, it proposes an optional peak heat load metric of around 10 to 15 W/m², which it argues would simplify compliance and support heat pump sizing.

The Trust will also run "respond-a-long" webinars to help members prepare their own responses.