Building regulations - proposed changes to energy and environmental standards: stage 2 consultation and BRIA
Consultation on proposed changes to energy and environmental standards in the Scottish Building Regulations. Updates to guidance supporting the Building (Scotland) Regulations 2004 (as amended) and the Building (Procedure) (Scotland) Regulations 2004 (as amended).
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Part of
3 The Scottish ‘Equivalent’ to the Passivhaus Standard - Option Development
3.1 Introduction
The subject of this consultation is change to requirements set within guidance to the Scottish building regulations to deliver a Scottish ‘equivalent’ to the Passivhaus standard, with the intent that these changes will deliver two outcomes:
- improvements to the setting of energy and environmental (ventilation) performance standards for new buildings, leading to lower energy demand (and reduced running costs) and a healthy indoor environment; and,
- improvements to the design and construction process to give greater assurance that compliance, and therefore the performance sought, is delivered in practice.
To achieve the two outcomes, the proposals, as set out in the stage two consultation to deliver a Scottish ‘equivalent’ to the Passivhaus standard, are discussed in sections 3.2 to 3.14 below.
Detailed costings are made available for the review of energy standards for new dwellings and buildings. This, alongside costings for other elements, will be subject to further development, based upon consultation responses, in support of final recommendations to Ministers.
3.1.1. Benefits arising from policy objective
A reduction in energy demand (running costs) and associated greenhouse gas emissions from new dwellings and new building work provides a range of benefits, including:
- a significant and positive contribution to Government targets set for the reduction in greenhouse gas emissions;
- reduces energy costs arising from the operation of new buildings;
- reduces use of finite natural resources and promotes development and adoption of systems that incorporate renewable energy sources; and,
- an increased benefit where buildings are altered, extended or converted and also where existing building elements and equipment are replaced, where this must be to the current standards.
An improvement in the health of the indoor environment in new dwellings and new building work provides a range of benefits, including:
- an adequate and healthy supply of air for human occupation of a building;
- can aid reduce the effects of moisture in various forms; and,
- reduce the risk to health of occupants from overheating.
Improvements to the design and construction to give greater assurance that compliance, and therefore the performance sought, is delivered in practice will offer a means of demonstrating that an informed and robust approach to compliance has been applied to the standards related to energy and environmental standards. This provides greater assurance that the benefits indicated above are materialised.
3.1.2. Sectors and groups affected
Sectors and groups affected can be categorised as:
- persons procuring or occupying new buildings or building work, who may need to bear additional costs associated with delivering buildings which have improved energy performance. Whilst this relates to a specific activity, the group who may be affected at one time or another can be considered to be the majority of the population;
- developers who, in addition to the above, would have to review existing building specification, construction detailing and potentially, methods of working. This might include, where relevant, seeking amended Scottish type approvals for standard construction, possibly sooner than otherwise intended;
- building materials and component manufacturers, who may need to review and introduce changes to products and literature to address revised performance standards;
- those involved with the energy aspects of building design and construction, who would have to familiarise themselves with any revised standards and methodologies;
- building services contractors, who may need to invest to increase the capacity for commissioning and testing of buildings and engineering services; and,
- local authority verifiers, who may need to arrange training of staff on changes to energy standards and guidance, to ensure these can be verified at design submission and during construction where necessary.
3.2 Delivery programme
As part of the laying of amendment regulations in December 2024 the Scottish Government applied a coming into force date of 31 March 2028 to enable the construction sector to prepare for the changes.
As the development of the Stage 2 proposals, supporting guidance and assessment tools has taken longer than originally anticipated, the timetable set out in the Stage 1 consultation has been reviewed. Following analysis of consultation responses, we now aim to publish guidance and approved methodologies under standard 6.1 in Autumn 2027.
Consequently, to maintain a sufficient industry preparation period, we will amend the implementation date in regulations to Autumn 2029. We will also consider the most appropriate approach, including introducing the standard in full, phasing it in, or supporting voluntary adoption before compliance becomes mandatory.
3.3 Alternative means of compliance
Responses to the July 2024 stage one consultation indicated strong support to amend standard 6.1 ‘Energy demand’ to recognise Passivhaus certification as an alternative means of compliance. This change will be progressed for implementation alongside wider review changes.
It is anticipated that such a change will require amendments to the Building (Scotland) Regulations 2004 (as amended), in particular paragraph 6.1 of Schedule 5.
The Passivhaus standard is a well-established voluntary standard. The standard is focused on delivering buildings with very low energy demand and high levels of occupant comfort through an informed approach to the optimisation of building form, orientation and design and effective quality assurance processes. There is increasing recognition and application of the standard, which contributes positively to overall energy and net zero objectives.
Given that the proposal to recognise Passivhaus certification as an alternative means of compliance will be voluntary any potential cost/emissions uplift or benefit will only be experienced by those who voluntarily decide to go through the Passivhaus process and will not form part of mandatory standards for the whole of Scotland.
3.4 Primary compliance metric – delivered energy
Delivered energy (as opposed to primary energy) remains the main compliance metric for standard 6.1 ‘Energy demand’ as this continues to be the most relevant metric for those that occupy and manage buildings. We propose to present unregulated loads as information sitting outwith but alongside the delivered energy metric.
Given that no change to the February 2023 energy standards is proposed, no further analysis is provided on this element within this Impact Assessment.
3.5 Secondary compliance metric – space heating demand
Proposals introduce a space heating demand rate as calculated through the approved methodologies, that takes into account the fabric efficiency of a new dwelling and new building.
A focus on space heating demand is likely to help reduce energy demand for space heating, which still forms a significant portion of the overall delivered energy consumption in new dwellings and buildings. This could also ensure that a good level of fabric insulation is incorporated in building work, especially to construction elements which would be difficult or costly to upgrade in the future.
The level at which the space heating demand rate is set will be defined by the level of challenge options as indicated in section 3.8 and 3.10 below. The costs and benefits are indicated in the corresponding sections.
3.6 Method of target setting
It is proposed that the current notional dwelling and notional building target setting method within standard 6.1 ‘Energy demand’ is replaced with a set of target range tables. The ranges being determined by a limited number of variables. For new dwellings: location, archetype, orientation and dwelling heat source. For new non-domestic buildings: location, building type, activity types, building heat source and orientation.
Closing down the number of variables by which a target can fluctuate could increase the focus on items that improve the energy efficient built form of that building. The level at which these target rates are set will be defined by the level of challenge options as indicated in section 3.8 and 3.10 below. The costs and benefits are indicated in the corresponding sections.
3.7 Fabric performance for new dwellings
The maximum ‘backstop’ U-values within guidance to standard 6.2 ‘Building insulation envelope’ are proposed to remain unchanged.
It is proposed to set a maximum upper limit of 5 m3/(h.m2) to the declared design air infiltration rate. EPC data for current new dwellings and buildings indicate that the average air tightness test result is below 5 m3/(h.m2) and it is anticipated that further focus on air tightness will help to reduce energy demand for space heating, which still forms a significant portion of the overall delivered energy consumption in new dwellings and buildings.
3.8 Level of challenge for new dwellings
Research was commissioned to assess and identify potential improvements in energy performance for new domestic buildings and to evaluate the costs of improvement measures. This was to inform the setting of targets, or level of challenge, set within energy standards.
Three level of challenge options for new dwellings are presented resulting in aggregate emissions reductions of between 0 and 37% against the February 2023 energy standards.
Additionally, where new dwellings are supplied from a high efficiency communal heating system it is proposed that dwellings supplied from such a source are able to report the net efficiency of the heat supply rather than the current default 100% efficiency.
Cost and energy models were developed based on four dwelling archetypes derived from an analysis of an extract of the Energy Performance Certificate database for new domestic buildings.
Currently, within the February 2023 energy standards, specifications for the level of challenge to be achieved for new dwellings are provided for the two main space heating fuels (electricity in the form of an air source heat pump and supplied heat in the form of a heat network). An additional, all other solutions specification is provided based on a gas solution.
The proposals within the stage two consultation retain three heating fuel specifications for the level of challenge:
- Electricity (air source heat pump)
- Supplied heat (heat network)
- All other solutions (direct electric)
Following the identification of baseline levels of performance i.e. that being delivered by the February 2023 energy standards, three level of challenge specifications were identified and consultation proposals are being taken forward using these specification options:
- Good Practice
- Best Practice
- Business as usual i.e. retain current February 2023 energy standards
These specification options, when aggregated to a national profile are assessed at delivering a 6.5%, 37% and 0% reduction in annual greenhouse gas emissions respectively.
Option 1 – Reduce energy demand and associated greenhouse gas emissions through building regulations, with revised performance measures for new dwellings. Within this option, a good practice level of challenge is considered.
Option 2 – Reduce energy demand and associated greenhouse gas emissions through building regulations, with revised performance measures for new dwellings. Within this option, a best practice level of challenge is considered.
Option 3 – Do nothing. With this option, a Business as Usual level of challenge is considered.
Reducing Greenhouse Gas Emissions
The number of new buildings per annum may account for a change in less than 1% of the entire building stock, however, by the year 2045, buildings built from this point onwards will account for a substantial percentage of our total building stock.
It is therefore vital that new buildings continue to make a contribution to further reductions in energy demand and associated emissions.
The outcomes of this review support the Government’s agenda to tackle climate change and reducing the adverse effect of greenhouse gas emissions on the environment. The Scottish Government’s commitment to net zero emissions by 2045 means that future energy performance improvements to buildings, new and existing, will remain a strong review agenda.
Option 1 – Good practice
This option offers meaningful benefit in respect of the objectives of this review – to reduce delivered energy demand and associated greenhouse gas emissions from new dwellings and new building work. The potential annual abatement associated with the occupation and use of new dwellings for an implemented good practice level of challenge is assessed in Table 1.
| New Dwellings | Option 1 – Good Practice |
|---|---|
| Annual abatement (%) | 6.5% |
| Annual abatement (kT) | 44 kt CO2e |
In assessing the overall cost/benefit for dwellings, the appraisal time period for estimating the impact of the policy is 10 years and assumed 60 years building life from the year of construction.
Benefits in adopting the good practice level of challenge proposed in option 1, to reducing energy demand and emissions include:
- an established delivery method by setting standards within Scottish building regulations. This has proved to be an equitable and robust way of improving the energy performance of new dwellings. All new dwellings which are heated (or cooled) or new building work within existing buildings will attract the application of revised minimum standards;
- the proposed level of challenge applies across all dwelling types regardless of servicing strategy, archetype and location;
- in addressing the performance of buildings, building regulations offers certainty that all new building work to all new and existing dwellings will result in improved performance. This allows a quantitative assessment of improvement, which will assist the Government in meeting its targets for emissions reductions; and,
- where subject to building regulations and a mandatory need to address improved building performance, those persons commissioning building work have the incentive to meet the regulations in the most cost effective manner possible. This is supported and encouraged by the use of functional standards and supporting guidance within building regulations, which allows flexibility in solutions and value engineering.
Option 2 – Best practice
This option offers significant benefit in respect of the objectives of this review – to reduce delivered energy demand and associated greenhouse gas emissions from new dwellings and new building work. The potential annual abatement associated with the occupation and use of new dwellings for an implemented best practice level of challenge is assessed in Table 2.
| New Dwellings | Option 2 – Best Practice |
|---|---|
| Annual abatement (%) | 37% |
| Annual abatement (kT) | 252 kt CO2e |
In assessing the overall cost/benefit for dwellings, the appraisal time period for estimating the impact of the policy is 10 years and assumed 60 years building life from the year of construction.
Benefits in adopting the best practice option of level of challenge proposed in option 2 are the same as set out in option 1. Noting that increased specification does affect the cost/benefit analysis reported for the implemented change.
Option 3 – Do nothing
As noted above, the Scottish Government is committed to the delivery of net-zero greenhouse gas emissions by 2045. Whilst building regulations have reduced emissions from new buildings substantially since 1990, doing nothing offers no further contribution towards meeting national targets for emissions reduction with no benefits identified which relate to the intended objective.
Doing nothing would result in new dwellings which continue to produce emissions at current levels, creating a greater challenge for the future. This option would not support the delivery of climate change targets and may lead to buildings requiring expensive work at a later date to improve their energy performance.
Given the Scottish Government commitment to reducing greenhouse gas emissions, a potential reputational risk may also arise if this option was adopted.
Monetised benefits
Potential savings achievable through implementation of options 1 and 2 are categorised as direct savings to building users and costs to Government from not taking actions, as follows:
- direct savings to building users through reduction in energy demand and reduced fuel costs; and,
- emissions reductions from reduced fuel consumption are valued using the guidance provided by HM Treasury Green Book supplementary appraisal guidance on valuing energy use and greenhouse gas emissions.
Option 1 – Good practice
Costs include ongoing cost of energy used, capital construction costs, ongoing maintenance costs and lifecycle replacements over their lifetime. Full costing research which informed this review and which forms part of the consultation package is published online. The following tables are drawn from the above research.
Table 3 indicates that the good practice level of challenge option results in an 8% reduction in household fuel costs per year.
| New Dwellings | Option 1 – Good Practice |
|---|---|
| Counterfactual (total £/yr) | 1,744 |
| Reduction in household fuels cost (£/yr) | 142 |
| Percentage reduction | 8% |
When calculated, Table 4 indicates that the good practice level of challenge option results in a capital cost reduction for new dwellings of between 1 and 2%.
| New Dwellings | Archetype | ASHP | Direct Electric | Heat Network |
|---|---|---|---|---|
| Counterfactual | End Terrace | £159,372 | £162,165 | £160,447 |
| Good Practice | End Terrace | £156,425 | £160,785 | £159,064 |
| Counterfactual | Mid Terrace | £146,703 | £148,917 | £147,377 |
| Good Practice | Mid Terrace | £144,033 | £147,601 | £146,078 |
| Counterfactual | Detached | £203,798 | £206,363 | £204,003 |
| Good Practice | Detached | £199,766 | £203,899 | £201,535 |
| Counterfactual | Flats | £2,040,593 | £1,994,712 | £2,024,475 |
| Good Practice | Flats | £2,015,554 | £1,968,777 | £1,999,590 |
Table 5 combines the reduction in annual fuel costs and capital cost of construction with ongoing maintenance costs and lifecycle replacements over a dwellings lifetime for the good practice level of challenge uplift option.
| New Dwellings | Option 1 – Good Practice |
|---|---|
| Counterfactual total (£m/yr) | 12,340 |
| Total financial uplift (£m/yr) | 71 |
| Percentage uplift | 0.6% |
Option 2 – Best practice
Costs include ongoing cost of energy used, capital construction costs, ongoing maintenance costs and lifecycle replacements over their lifetime. Full costing research which informed this review and which forms part of the consultation package is published online. The following tables are drawn from the above research.
Table 6 indicates that the best practice level of challenge option results in an 34% reduction in household fuel costs per year.
| New Dwellings | Option 2 – Best Practice |
|---|---|
| Counterfactual (total £/yr) | 1,744 |
| Reduction in household fuels cost (£/yr) | 598 |
| Percentage reduction | 34% |
When calculated, Table 7 indicates that the best practice level of challenge option results in a capital cost increase for new dwellings of between 4 and 5%.
| New Dwellings | Archetype | ASHP | Direct Electric | Heat Network |
|---|---|---|---|---|
| Counterfactual | End Terrace | £159,372.00 | £162,165.00 | £160,447.00 |
| Best Practice | End Terrace | £166,979.00 | £168,234.00 | £166,512.00 |
| Counterfactual | Mid Terrace | £146,703.00 | £148,917.00 | £147,377.00 |
| Best Practice | Mid Terrace | £153,664.00 | £154,524.00 | £153,000.00 |
| Counterfactual | Detached | £203,798.00 | £206,363.00 | £204,003.00 |
| Best Practice | Detached | £214,376.00 | £215,404.00 | £213,040.00 |
| Counterfactual | Flats | £2,040,593.00 | £1,994,712.00 | £2,024,475.00 |
| Best Practice | Flats | £2,131,740.00 | £2,076,333.00 | £2,107,147.00 |
| New Dwellings | Option 2 – Best Practice |
|---|---|
| Counterfactual total (£m/yr) | 12,340 |
| Total financial uplift (£m/yr) | 862 |
| Percentage uplift | 5.5% |
Option 3 – Do nothing
This option presents no implementation costs.
National Impact – New Dwellings
Based on the build/fuel mix, capital and lifetime costs, benefits and transition period applied, the national costs and benefits for Options 1 and Option 2 are shown in Table 9. The counterfactual is Option 3 - the February 2023 energy standards. This is not shown as the cost and benefits are assessed as zero for this option. The analysis is based on the HM Treasury Green Book standards and accompanying supplementary guidance on valuation of energy use. Refer to the full domestic research for relevant assumptions and further commentary.
| New Dwellings | Option 1 - Good Practice | Option 2 - Best Practice |
|---|---|---|
| Reduction in cost of energy used (£m) | 142 | 598 |
| Uplift in capital, maintenance and replacement costs (£m) | 213 | 1,460 |
| Total financial cost uplift (£m) | 71 | 862 |
| Total carbon emissions (£m) | 9 | 49 |
| Air quality impact (£m) | 0.36 | 2.00 |
| Net cost (£m) | 62 | 811 |
| Gas consumption (GWh) | 429 | 2,871 |
| Electricity consumption (GWh) | 3,304 | 16,421 |
| CO2 emissions (tCO2e) | 44,103 | 251,500 |
3.9 Standard 6.1 compliance approved methodologies for dwellings
An interim version of a Scottish ‘wrapper’ linked to the UK Government Home Energy Model is presented for consultation as a work in progress compliance tool, to be developed further before being adopted as an approved methodology prior to implementation.
Development of compliance methodologies has been a continuous process to ensure that they represent innovations in technology and the complexities of low and zero energy dwellings. We will continue to work with software developers to understand the cost impacts of such a change.
It is proposed that a modified version of the Passivhaus Planning Package (PHPP) will also be developed and adopted as an approved compliance methodology. This will allow flexibility in the choice of methodologies, however, the use of one methodology over the other should not give a benefit in terms of complying with standard 6.1.
3.10 Level of challenge for new non-domestic buildings
Research was commissioned to assess and identify potential improvements in energy performance for new non-domestic buildings and to evaluate the costs of improvement measures. This was to inform the setting of targets, or level of challenge, within the set of energy standards.
Three level of challenge options for new buildings are presented resulting in aggregate emissions reductions of between 0 and 11.4% against the February 2023 energy standards.
Cost and energy models were developed based on seven building types split across eleven sub types. These were derived from an analysis of an extract of the Energy Performance Certificate database for new buildings:
- Shallow office; district heat network (DHN) and natural ventilation (NV)
- Deep office; heat pump (HP) and air conditioning (AC)
- Health centre; DHN and mechanical ventilation (MV)
- Hotel; direct electric (DE) and NV
- Retail; HP and AC
- Retail; HP and MV
- Secondary school; DHN and AC
- Secondary school; HP and MV
- Secondary school; DE and NV
- Warehouse distribution; HP and AC
- Warehouse distribution; DE and MV
Currently, within the February 2023 energy standards, specifications to achieve the level of challenge to be achieved for new buildings is provided for the two main space heating fuels (electricity in the form of an air source heat pump and supplied heat in the form of a heat network). An additional, legacy specification is provided based on a gas solution.
The proposals within the stage two consultation retain three heating fuel specifications for the level of challenge:
- Electricity (air source heat pump)
- Supplied heat (heat network)
- All other solutions (direct electric)
Following the identification of baseline levels of performance i.e. that being delivered by the February 2023 energy standards, three level of challenge specifications were identified and consultation proposals are being taken forward using these specification options. Note that the options referenced are options within the non-domestic analysis and are not combined with the domestic options discussed above:
- Option 1 – Business as usual i.e. retain current February 2023 energy standards
- Option 2 – Medium level
- Option 3 – High level
Note that the non-domestic research had a low level of challenge option instead of a Business as usual option. The Business as usual option is progressed alongside the medium and high options.
These specification options, when aggregated to a national profile are assessed at delivering a 0%, 10.1% and 11.4% reduction in initial annual greenhouse gas emissions respectively.
Option 1 – Do nothing. With this option, a Business as Usual level of challenge is considered.
Option 2 – Reduce energy demand and associated greenhouse gas emissions through building regulations, with revised performance measures for new buildings. Within this option, a medium level of challenge is considered.
Option 3 – Reduce energy demand and associated greenhouse gas emissions through building regulations, with revised performance measures for new buildings. Within this option, a high level of challenge is considered.
Reducing Greenhouse Gas Emissions
The number of new buildings per annum may account for a small change in the entire building stock, however, by the year 2045, buildings built from this point onwards will account for a substantial percentage of our total building stock.
It is therefore vital that new buildings continue to make a contribution to further reductions in energy demand and associated emissions.
The outcomes of this review support the Government’s agenda to tackle climate change and reducing the adverse effect of greenhouse gas emissions on the environment. The Scottish Government’s commitment to net zero emissions by 2045 means that future energy performance improvements to buildings, new and existing, will remain a strong review agenda.
Option 1 – Do nothing
As noted above, the Scottish Government is committed to the delivery of net-zero greenhouse gas emissions by 2045. Whilst building regulations have reduced emissions from new buildings substantially since 1990, doing nothing offers no further contribution towards meeting national targets for emissions reduction with no benefits identified which relate to the intended objective.
Doing nothing would result in new buildings which continue to contribute to produce emissions at current levels, creating a greater challenge for the future. This option would not support the delivery of climate change targets and may lead to buildings requiring expensive work at a later date to improve their energy performance.
Given the Scottish Government commitment to reducing greenhouse gas emissions, a potential reputational risk may also arise if this option was adopted.
Option 2 – Medium level
This option offers meaningful benefit in respect of the objectives of this review – to reduce delivered energy demand and associated greenhouse gas emissions from new buildings and new building work. The potential annual abatement associated with the occupation and use of new buildings for an implemented medium level of challenge is assessed in Table 10.
| New Buildings | Option 2 – Medium level |
|---|---|
| Annual abatement (%) | 10.1% |
| Annual abatement (kT) | 62 kt CO2e |
In assessing the overall cost/benefit for buildings, the appraisal time period for estimating the impact of the policy is 10 years and assumed 60 years building life from the year of construction.
Benefits in adopting the medium level of challenge proposed in option 2, to reducing energy demand and emissions include:
- An established delivery method by setting standards within Scottish building regulations. This has proved to be an equitable and robust way of improving the energy performance of new buildings. All new buildings which are heated (or cooled) or new building work within existing buildings will attract the application of revised minimum standards.
- The proposed level of challenge applies across all buildings types regardless of servicing strategy, archetype and location.
- In addressing the performance of buildings, building regulations offers certainty that all new building work to all new and existing buildings will result in improved performance. This allows a quantitative assessment of improvement, which will assist the Government in meeting its targets for emissions reductions.
- Where subject to building regulations and a mandatory need to address improved building performance, those persons commissioning building work have the incentive to meet the regulations in the most cost effective manner possible. This is supported and encouraged by the use of functional standards and supporting guidance within building regulations, which allows flexibility in solutions and value engineering.
Option 3 – High level
This option offers significant benefit in respect of the objectives of this review – to reduce delivered energy demand and associated greenhouse gas emissions from new buildings and new building work. The potential annual abatement associated with the occupation and use of new buildings for an implemented high level of challenge is assessed in Table 11.
| New Buildings | Option 3 – High level |
|---|---|
| Annual abatement (%) | 11.4% |
| Annual abatement (kT) | 82 kt CO2e |
In assessing the overall cost/benefit for buildings, the appraisal time period for estimating the impact of the policy is 10 years and assumed 60 years building life from the year of construction.
Benefits in adopting the high level option of level of challenge proposed in option 3 are the same as set out in option 2. Noting that increased specification does affect the cost/benefit analysis reported for the implemented change.
Monetised benefits
Potential savings achievable through implementation of options 2 and 3 are categorised as direct savings to building users and costs to Government from not taking actions, as follows:
- Direct savings to building users through reduction in energy demand and reduced fuel costs
- Emissions reductions from reduced fuel consumption are valued using the guidance provided by HM Treasury Green Book supplementary appraisal guidance on valuing energy use and greenhouse gas emissions
Option 1 – Do nothing
This option presents no implementation costs.
Option 2 – Medium level
Costs include ongoing cost of energy used, capital construction costs, ongoing maintenance costs and lifecycle replacements over a building’s lifetime. Full costing research which informed this review and which forms part of the consultation package is published online. The following information is drawn from that research.
| New Buildings | Option 2 – Medium |
|---|---|
| Total reduction in building fuels cost (£m/yr) | 216 |
When calculated, Table 13 indicates that the medium level of challenge option results in a capital cost increase for new buildings of between 1 and 7% depending on the building sub-type:
Combining the annual fuel costs and capital cost of construction with ongoing maintenance costs and lifecycle replacements over a building lifetime results in a total cost uplift of £48M for the medium level of challenge.
| New Buildings | Sub-type | Capital Cost | Uplift on counterfactual |
|---|---|---|---|
| Counterfactual | Shallow office; DHN & AC | £5,400,000 | |
| Medium level | Shallow office; DHN & AC | £5,461,837 | 1% |
| Counterfactual | Deep office; HP & AC | £42,000,000 | |
| Medium level | Deep office; HP & AC | £42,489,279 | 1% |
| Counterfactual | Health centre; DHN & MV | £8,977,500 | |
| Medium level | Health centre; DHN & MV | £9,059,415 | 1% |
| Counterfactual | Hotel; DE & NV | £3,188,250 | |
| Medium level | Hotel; DE & NV | £3,253,367 | 2% |
| Counterfactual | Retail; HP & AC | £2,877,057 | |
| Medium level | Retail; HP & AC | £3,069,935 | 7% |
| Counterfactual | Retail; HP & MV | £2,750,000 | |
| Medium level | Retail; HP & MV | £2,942,817 | 7% |
| Counterfactual | Secondary school; DHN & AC | £25,203,487 | |
| Medium level | Secondary school; DHN & AC | £25,581,001 | 1% |
| Counterfactual | Secondary school; HP & MV | £24,572,721 | |
| Medium level | Secondary school; HP & MV | £25,254,349 | 3% |
| Counterfactual | Secondary school; DE & NV | £24,037,650 | |
| Medium level | Secondary school; DE & NV | £24,244,952 | 1% |
| Counterfactual | Warehouse distribution; HP & AC | £9,471,006 | |
| Medium level | Warehouse distribution; HP & AC | £9,788,744 | 3% |
| Counterfactual | Warehouse distribution; DE & MV | £9,699,612 | |
| Medium level | Warehouse distribution; DE & MV | £9,867,992 | 2% |
Option 3 – High level
Costs include ongoing cost of energy used, capital construction costs, ongoing maintenance costs and lifecycle replacements over a building’s lifetime. Full costing research which informed this review and which forms part of the consultation package is published online. The following information is drawn from that research.
| New Buildings | Option 2 – High |
|---|---|
| Total reduction in building fuels cost (£m/yr) | 255 |
When calculated, Table 15 indicates that the high level of challenge option results in a capital cost increase for new buildings of between 2 and 11% depending on the building sub-type:
| New Buildings | Sub-type | Capital Cost | Uplift on counterfactual |
|---|---|---|---|
| Counterfactual | Shallow office; DHN & AC | £5,400,000 | |
| High Level | Shallow office; DHN & AC | £5,551,117 | 3% |
| Counterfactual | Deep office; HP & AC | £42,000,000 | |
| High Level | Deep office; HP & AC | £43,514,424 | 4% |
| Counterfactual | Health centre; DHN & MV | £8,977,500 | |
| High Level | Health centre; DHN & MV | £9,146,026 | 2% |
| Counterfactual | Hotel; DE & NV | £3,188,250 | |
| High Level | Hotel; DE & NV | £3,298,074 | 3% |
| Counterfactual | Retail; HP & AC | £2,877,057 | |
| High Level | Retail; HP & AC | £3,181,828 | 11% |
| Counterfactual | Retail; HP & MV | £2,750,000 | |
| High Level | Retail; HP & MV | £3,014,346 | 10% |
| Counterfactual | Secondary school; DHN & AC | £25,203,487 | |
| High Level | Secondary school; DHN & AC | £25,958,467 | 3% |
| Counterfactual | Secondary school; HP & MV | £24,572,721 | |
| High Level | Secondary school; HP & MV | £25,693,952 | 5% |
| Counterfactual | Secondary school; DE & NV | £24,037,650 | |
| High Level | Secondary school; DE & NV | £24,602,747 | 2% |
| Counterfactual | Warehouse distribution; HP & AC | £9,471,006 | |
| High Level | Warehouse distribution; HP & AC | £10,133,161 | 7% |
| Counterfactual | Warehouse distribution; DE & MV | £9,699,612 | |
| High Level | Warehouse distribution; DE & MV | £10,212,372 | 5% |
Combining the annual fuel costs and capital cost of construction with ongoing maintenance costs and lifecycle replacements over a building lifetime results in a total cost uplift of £349M for the high level of challenge.
National Impact – New Buildings
Based on the build/fuel mix, capital and lifetime costs, benefits and transition period applied, the national costs and benefits for Options 2 and Option 3 are shown in Table 16. The counterfactual is Option 1 - the February 2023 energy standards. This is not shown as the cost and benefits are zero for this option. The analysis is based on the HM Treasury Green Book standards and accompanying supplementary guidance on valuation of energy use. Refer to the full non-domestic research for relevant assumptions and further commentary.
| New Buildings | Option 2 - Medium | Option 3 – High |
|---|---|---|
| Reduction in total cost of energy used (£M) | 216 | 255 |
| Incremental costs for construction, maintenance and replacement (£m) | 264 | 604 |
| Total financial cost uplift (£m) | 48 | 349 |
| Total carbon emission savings (£m) | 14 | 18 |
| Air quality impact savings (£m) | 1 | 1 |
| Net cost (£m) | 33 | 330 |
| Amount of electricity saved (GWh) | 8,681 | 9,836 |
| Amount of CO2 saved (MtCO2) | 0.062 | 0.082 |
3.11 Standard 6.1 compliance approved methodologies for new non-domestic buildings
An interim Scottish version of the Simplified Building Energy Model v7 is presented for consultation as a work in progress compliance tool, to be developed further before being adopted as an approved methodology prior to implementation.
Development of compliance methodologies has been a continuous process to ensure that they represent innovations in technology and the complexities of low and zero energy buildings. We will continue to work with software developers to understand the cost impacts of such a change.
It is proposed that a modified version of the Passivhaus Planning Package (PHPP) will also be developed and adopted as an approved compliance methodology. This will allow flexibility in the choice of methodologies, however, the use of one methodology over the other will not give a benefit in terms of complying with standard 6.1.
3.12 Ventilation and indoor air quality
It is proposed to continue to accept any system/solution of achieving the performance sought in standard 3.14 ‘Ventilation’. However, we will procure research outwith the stage two consultation to understand where additional guidance would be beneficial, including on the use of Mechanical Ventilation with Heat Recovery in new dwellings and non-domestic buildings. Engagement will commence at the appropriate time to be capture in confirmed guidance.
3.13 Overheating
Scottish Government has initiated work (contractor appointed) to review and update the guidance in support of standard 3.28 ‘Overheating risk’ to identify further information that will provide greater clarity on the actions required to achieve compliance with the standard. The includes guidance on the use of PHPP as an additional option to assess and mitigate overheating risk in dwellings and some non-residential buildings. This work will be confirmed and captured within guidance
3.14 Compliance and assurance
We propose to introduce a ‘Building Standards Energy and Environmental Compliance Handbook’ which will provide guidance on the production of the design and construction statements as now required by the Building (Procedure) (Scotland) Amendment Regulations 2024. Application of such guidance is intended to also offer a means of demonstrating that an informed and robust approach to compliance has been applied to the standards related to energy and environmental performance.
We consider it is important to emphasise that provisions introduced into guidance or via new guidance should reference current good practice and are intended to reinforce the need for this, not create new obligations. Noting that some expansion of provisions specific to the building standards system, such as the requirement to submit design and construction statements, will attract some small additional on-costs. It is not, therefore, expected that a more informed and evidenced approach to the delivery of energy efficiency in buildings should result in significant additional capital cost to development (compared to expected practice), beyond the need to engage a coordinating individual to manage the process.
Contact
Email: buildingstandards@gov.scot