Building regulations 2025 - new non-domestic buildings: energy standard improvements - modelling report

1. Introduction

1.1 Project aims

The overall aim of this project was to assess and identify the potential for further improvement in energy performance for new non-domestic buildings constructed in Scotland set via Standard 6.1 (Energy Demand) and supporting guidance within The Scottish Government’s Building Standards Technical Handbooks. This was to inform the setting of targets within the next set of energy standards, programmed for implementation in 2028.

Standard 6.1 of the Scottish Building Regulations (Scottish Government, 2004, as amended) specifies that for new domestic and non-domestic buildings:

“Every building must be designed and constructed in such a way that:

“a) the energy performance is calculated in accordance with a methodology of calculation approved under regulation 7(a) of the Energy Performance of Buildings (Scotland) Regulations 2008;

“b) it is a nearly zero-energy building; and

“c) it is capable of reducing the energy demand of the building.”

The accompanying technical handbooks (Scottish Government - Building Standards Division, 2025) provide guidance on achieving this standard.

The main outputs required from this project were:

• A set of proposed revised notional buildings specifications for application within the non-domestic standards that would sit within the approved Standard 6.1 compliance methodology.
• Illustration of the costs and benefits of the options assessed for the revised notional building.
• Assessment, illustration and commentary on the difference in outcome from modelling a given specification in both SBEM and PHPP.
• Investigation into the potential introduction of a Target Space Heating Demand Rate metric to have primacy over the current Target Delivered Energy Rate metric.

1.2 Policy Context

In 2019, the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019 committed to reducing Scottish emissions to net zero by 2045. In November 2024, further legislative updates as part of the Climate Change (Emissions Reduction Targets) (Scotland) Act 2024 (Scottish Government, 2024) came into force, introducing the framework for a carbon budget-based approach for setting emissions reduction targets up to 2045. Each carbon budget will cover a five-year period to assess progress in the actions and policies that will contribute to achievement of Net Zero emissions by 2045.

1.3 Policy and Research Implications

The research undertaken as part of the project, the proposals made for the notional building, and the findings from the cost benefit assessment may raise issues which have implications for policy or strategy beyond Building Standards Section 6, or which require further research or action. Key implications have been highlighted in the report.

Outside the scope of Building Standards Section 6, the New Building Heat Standard has mandated the use of zero direct emission heating systems for most new buildings. Other work will be required to facilitate the transition to low carbon heating in existing buildings, and to support an increase in localised embedded renewable energy generation more generally. This is in the context of future standards, and of current electricity grid constraints and a drive for future electrification across different sectors. Supportive measures are also likely to be needed to facilitate other future changes in construction practices associated with improvements to standards set by the notional building. Changes to Section 6 may also require, or benefit from, a review of some of the guidance in other areas of the Technical Handbooks, for example parts of Section 7.