The government has published its updated Building Regulations for England which includes amendments to Approved Documents- Part F (ventilation), and Part L (Conservation of fuel and power), as well as the release of a new approved document for Overheating (Part O).
Here we take you through the major changes taking place in 2022 in respect of energy conservation in buildings and ventilation.
Government Targets
New and existing homes produce around 20% of all carbon emissions in the UK. As part of the efforts to meet the UK’s ambitious target to reduce greenhouse gas emissions to ‘net-zero’ by 2050, the government has committed to introducing what they are calling the ‘Future Homes Standard’ in 2025. This anticipates that an average home will have 75-80% fewer carbon emissions than a home constructed to the current national standards for energy efficiency. Their plan is to realise this by introducing very high fabric efficiency standards combined with low carbon heating systems. Beyond 2025 further uplift is expected to form another stepping stone towards meeting the ambition for net-zero carbon in 2050.
The Consultation
As a transitional stepping-stone towards that target, the Government launched a Future Homes Standard consultation at the end of 2019. This considered options for uplifting standards in Approved Document L1 covering energy efficiency in dwellings. Being aware of the sensitive interaction between energy efficiency, airtightness, and healthy ventilation standards, this was accompanied by proposals to revise Part F (Ventilation) and its associated Approved Document. The consultation covered buildings in England and ran until February 2020. Proposals for changes to Part L2 covering non-domestic buildings were also considered along with new measures to prevent overheating in homes built to the new standards
New Approved Documents
At the end of 2021 the government published new Approved Document F covering ventilation and L covering energy efficiency. Both were in 2 volumes with 1. dealing with dwellings and 2. covering buildings other than dwellings. They were accompanied by an all-new Approved Document O covering overheating in dwellings. New homes meeting the new standards should produce 31% less CO2 compared to those built to current standards.
Summary of Changes to the Building Regulations
Changes to Part F
- simplifying the approach for determining the ventilation rate and system design requirements for a dwelling
- changing the way that ventilation systems are presented in the Approved Document to reflect common design practices and on the basis of latest evidence relating to air quality in homes.
- introducing guidance to reduce the ingress of external air pollutants into the main body of the Approved Document.
- simplifying the structure and content of the guidance.
Changes to Part L
The Standard Assessment Procedure (SAP) methodology will likely be updated to version SAP 10.3 by the time Part L1 2021 comes into effect. This changes the building minimum energy performance target by introducing primary energy as a performance metric. This is in addition to the target fabric efficiency rate, target CO2 emissions and minimum standards for building fabric and system efficiencies. The new approved document also:-
- Upgrades the specification for a ‘notional dwelling’ that forms the basis for minimum performance using the SAP. That includes an expectation for incorporating a solar PV array and wastewater heat recovery.
- Improves the minimum insulation standards relating to extensions and alterations to buildings
- Improves the minimum efficiencies of fixed building services
- Future-proofs new dwellings to be ready for low-carbon heating systems
- Introduces a new Part L compliance (BREL) report including photographic evidence to improve compliance with Part L and as-built performance
- Introduces alternative test methods and targets for airtightness
- Helps to educate building occupiers on how to operate low-carbon homes by introducing mandatory home user guides for new dwellings
New Approved Document O – Overheating
The higher standards of energy efficiency are accompanied by a new approved document aimed at designing out the need for energy hungry air conditioning systems in dwellings that would otherwise be prone to overheating. The main elements are:-
- Provisions for limiting unwanted solar gain. Setting maximum glazed areas depending on the orientation of the façade and whether or not the building can be cross-ventilated.
- Requiring means to remove excess heat from indoors setting minimum opening areas
- 2 optional methods to demonstrate compliance. Either a fixed set of design rules or by using dynamic thermal modelling as covered in the CIBSE guidance document TM59.
- Under the latter method, we can expect greater use of measures such as shutters, blinds, overhangs, awnings and reflective glass on South facing elevations.
- The document underlines the importance of using passive measures for cooling and ventilation in preference to mechanical to the extent that it is practicable.
- Consideration to external noise and pollution cross-referencing to AD F
- Consideration of security of GF windows if they need to be open as part of the overheating mitigation strategy cross-referencing Part Q standards
- Sets down separate (‘high-risk location’) standards for Greater London that are more onerous.
- As with ventilation, there are rules on making owners and occupiers aware of how to use the building effectively with mandatory home user guides.
Transitional Provisions
The new standards will come into force on 15th June 2022. There will be a 12-month transition period ie any applications received before this date must start work by June 2023. Meaning after this date any new building regulations applications will be assessed under the new standards.
Rules on the transition were tightened to fast-track implementation, and prevent builders from lodging applications for large developments early to lock in the earlier standards for energy efficiency. Starting work to meet the June 2023 deadline applies to individual houses or blocks of flats and not to whole developments covered by an application.
Useful Links
To view the Future Homes Consultation: https://www.gov.uk/government/consultations/the-future-buildings-standard
New Approved Document L
New Approved Document F
New Approved Document O