Scottish Government outlines revised timeline in Stage 2 building regulations consultation

On 24 July, the Scottish Government published its Stage 2 consultation on the next revision to Scotland’s energy standards. The proposals form part of its ongoing work to introduce a ‘Passivhaus equivalent’ standard for new homes through the Building Standards.

The consultation follows the partial response to the Stage 1 consultation published earlier this year, which Elmhurst covered in full, here. That response indicated that the new standards would be introduced from 31 March 2028.

However, following a review of the programme and the additional time needed to develop the supporting guidance, assessment methodologies and software tools, the proposed implementation date has now moved to autumn 2029.

This Stage 2 consultation seeks views on proposed energy and environmental performance targets for the new standard and on proposals for an enhanced compliance process, including guidance to support the requirement to submit energy and environmental design and construction statements.

The full consultation can be viewed here and closes on 16^th October 2026.

We cover some of the main proposals in the consultation below:

Proposed uplift over current energy standards

The consultation sets out three options for the future energy performance requirements for new homes in Scotland:

• Option 1 – Good Practice: Equivalent to a 6% reduction in carbon emissions compared with the current 2023 energy standards. This option would improve the building fabric and would typically use an air source heat pump for space and water heating. Photovoltaic panels would also be required where an alternative heating system is used, such as direct electric heating or a heat network.
• Option 2 – Best Practice: Equivalent to a 37% reduction in carbon emissions compared with the current standards. This option would introduce a greater improvement in fabric performance and include mechanical ventilation with heat recovery (MVHR). Homes using an air source heat pump would also include photovoltaic panels.
• Option 3 – Current Standard: Retain the existing 2023 energy performance requirements for new homes, with no additional uplift.

Both the Good Practice and Best Practice options would strengthen fabric performance. However, the Best Practice option would introduce more demanding requirements, including MVHR and, where a heat pump is installed, photovoltaic panels.

Compliance Metrics

It was confirmed that the Delivered Energy Rate and Space Heat Demand Rate would form the basis of the metrics used to determine compliance for new homes in Standard 6.1. The Delivered Energy Rate will be calculated in the same manner as in the current Standard 6.1 i.e. will not take account of unregulated energy usage or energy exported to the grid.

The Space Heat Demand rate will be based on the fabric performance of the new home including insulation levels, thermal bridging and airtightness rates. It was confirmed that the following two metrics will form the basis of compliance for new in Standard 6.1:

• Delivered Energy Rate: This will measure the energy delivered to the home and will be calculated in the same way as under the current Standard. It will not include unregulated energy use, such as energy consumed by household appliances, or any energy exported to the electricity grid.
• Space Heat Demand Rate: This will measure the amount of energy needed to heat the home. It will be determined by the building’s fabric performance, including insulation levels, thermal bridging and airtightness.

Setting performance standards

Under the current approach, compliance targets are calculated in SAP 10.2 using a notional dwelling defined within the Building Standards. The consultation proposes replacing this method with a series of target performance tables. The relevant target range would be selected according to the home’s:

• Location
• Dwelling type
• Orientation
• Heating system

These characteristics would match those of the actual home when establishing its target Delivered Energy Rate. All other features of the notional dwelling would be based on fixed specifications, regardless of the materials, systems or construction details used in the proposed home.

This approach is intended to provide clearer and more consistent performance targets while still accounting for the main factors that influence a home’s energy use.

Calculation Methodologies

As confirmed in the stage one consultation the Standard 6.1 will be based on the use of the Home Energy Model with a Scottish wrapper. This is currently a work in progress but a consultation version of HEM with the Scottish wrapper can be accessed here.

It was also proposed that a modified version of the Passivhaus Planning Package (PHPP) will be developed and adopted as an approved compliance methodology for Standard 6.1.

Fabric standards

The consultation proposes the following requirements for new homes:

• U-values: The maximum backstop U-values set out in Standard 6.2 would remain unchanged.
• Airtightness testing: A new maximum air permeability rate of 5 m³/(h·m²) at 50 Pa would be introduced. New homes would therefore need to achieve an airtightness test result at or below this level.

Overheating

The Scottish Government is reviewing Standard 3.28, which currently sets out the requirements for managing overheating risk in Scotland.

As part of the next update to the Building Standards, the consultation considers whether the Passive House Planning Package (PHPP) could be used to assess overheating risk in new homes and certain non-domestic buildings.

Updated guidance will also be developed to support Standard 3.28. This is intended to give designers, developers and assessors greater clarity on the measures and evidence needed to demonstrate compliance.