The Scottish Government has launched a consultation on the next revision to the Building Standards, applicable to new buildings. The consultation seeks views on the form and approach that a Scottish equivalent to the Passivhaus standard, implemented through building regulations, should adopt.

What Does The Consultation Cover?

Proposed delivery programme

This consultation forms stage 1 of the delivery programme. Stage 2 will commence in 2025 and will incorporate further consultations on the detailed proposals for the new standards and compliance processes.

Stage 3 involves the implementation of the new standards, with two options proposed:

• an implementation of not less than three months after publication of the new standards in early 2026, or
• an introduction as a voluntary standard in early 2026 with a move to mandating the standard in early 2028. This is the approach currently proposed by Scottish Government.

Methodology

The government proposes that the Home Energy Model (HEM) be used with a Scottish wrapper, based on regional climate data, to support the changes proposed in the second consultation. This will be used to compare against Passive House Planning Package (PHPP), to determine whether PHPP can be used as an alternative method for demonstrating compliance to the standards.

For non-domestic buildings, SBEM continues to be used, with further refinements to the methodology expected.

Compliance metrics

Currently, Standard 6.1 requires compliance against the Delivered Energy Rate, which is based on regulated energy use of a building. The Passivhaus Standard uses the Primary Energy Renewable demand, which includes regulated and unregulated energy use and sets a maximum allowable Space Heat Demand rate.

The consultation proposes to retain the Delivered Energy Rate as the compliance standard. However, there is further consideration of whether a Space Heat Demand limit metric could be used.

Absolute metrics vs Targets

At present, compliance targets differ between Building Standards and Passivhaus standards. In Building Standards, they are set using a notional building which is the same size and form as the actual building, based on a set specification. However, Passivhaus uses an absolute target, regardless of the size or shape of the building, which rewards efficient building forms. The consultation proposes to stay with a target-based approach, using a notional building generated by HEM/SBEM.

Passivhaus certification as alternative method of compliance to standard 6.1?

Passivhaus certification is an established standard for assessing the performance of low energy buildings using the PHPP calculation procedure. Although Passivhaus uses different performance metrics, it is accepted that a building achieving Passivhaus standards would also achieve compliance with the Building Standards. Therefore, it is proposed that Passivhaus certification could be used as a means of demonstrating compliance with standards.

Call for information on current standards

There are further sections of the consultation that look for evidence on how the current standards are being met. For example, the Government are looking for confirmed specifications for the February 2023 standards to be shared, to support the development of the energy baseline for new buildings in future standards.

Further Information:

To view the consultation, please use the following link: https://consult.gov.scot/local-government-and-communities/building-regulations-passivhaus-equivalent/

The consultation closes on Wednesday 23rd October 2024.