Decarbonising buildings is central to achieving the UK government's net-zero target for 2050. However, these changes will not happen overnight, so the housebuilding industry is being set incremental targets along the way.
The Future Homes Standard, along with the Future Buildings Standard for non-domestic properties, were proposed as part of the government's two-part consultation on changes to the Building Regulations.
From 2025, new buildings must be net-zero-ready; which in practice means that they have to be constructed to a high standard of energy efficiency with low-carbon heating, avoiding the need for costly retrofit. New homes built to the Future Homes Standard should generate only 20–25% of the emissions of homes built to current requirements.
Given the transformation required in the design and construction of buildings, we must develop new skill sets and supply chains.
The government has implemented an interim uplift in standards to support this transition, and pave the way for the full Future Homes Standard in 2025. The uplift has applied since 15 June, and is being implemented through a series of new and updated Approved Documents under the Building Regulations in England.
Approved Document L deals with the conservation of fuel and power and the on-site generation of electricity.
Approved Document F sets out ventilation requirements.
Alongside these uplifted standards the government published two new Approved Documents in December, which also took effect on 15 June. Approved Document O includes measures to mitigate the effects of overheating, and Approved Document S introduces obligations to install infrastructure for the charging of electric vehicles.
The aim is that new homes complying with the uplifted requirements will reduce carbon emissions by 31% compared with those built to current standards. This will be achieved through a combination of low-carbon heating and increased fabric standards.
'New homes built to the Future Homes Standard should generate only 20–25% of the emissions of homes built to current requirements'
These changes, which are already having an impact on sites under development, should help smooth the transition to the Future Homes Standard in 2025. The government is now undertaking further research and analysis, alongside engagement with key industry players, on the full technical specification for the standard before full implementation.
The interim uplift will apply to individual buildings, rather than across whole development sites, as soon as work commences. This means that the Building Regulations will no longer be locked in at the start of works. Phased developments may therefore find that different regulations apply to different parts of the site over the course of the build programme.
Transitional arrangements have been put in place for situations where a building notice, initial notice or full plans have been submitted to a local authority before 15 June. In this case, there will be no obligation to comply with the interim uplift in regulation, provided that building work commences on site within 12 months.
Under the interim changes, new performance metrics have been introduced that seek to ensure a fabric-first approach. This includes a new metric for measuring energy efficiency: the primary energy rating. This measures energy use in dwellings, as well as taking into account the energy used to produce and transport the fuel source before it is used in the building.
The four-part performance metric now includes:
target primary energy rating, which is the principal metric
target emission rating, which is the secondary metric
target fabric energy efficiency rating
minimum standards for fabric and fixed building services, including airtightness and thermal bridging performance.
The target emission rate will no longer be used as the primary performance metric, in recognition that carbon emissions alone do not give a full picture of the energy performance of building performance over time. This is because it will become increasingly difficult to determine whether emissions reductions are a result of improved energy efficiency or a decarbonised electricity grid.
In addition to fabric improvements, technology will be key to achieving the 31% reduction in emissions.
Part L requires that efficient and decentralised systems that use renewable sources are given full consideration before building work starts. Heat pumps or connection to low-carbon district heating systems are identified as a way to meet this criterion, moving away from traditional fossil-fuel boilers.
Updated minimum dwelling and background ventilation rates have also been introduced under Part F, which require designers to consider a combination of passive ventilation and mechanical applications such as air conditioning.
There is emphasis on using all practicable means to achieve passive cooling before resorting to mechanical options. This is intended to avoid increasing the building's energy usage, as any mechanical systems must meet the Part L performance metrics.
Designers also need to consider carefully how they meet requirements for increased airtightness under Part L, so they do not affect the building's ventilation and air quality standards.
The new Part O meanwhile brings together previous regulation on overheating, and requires that new homes are kept at a comfortable temperature. New buildings must be designed to limit unwanted solar gains and minimise and remove any excess heat.
It is essential that the design phase aims to fulfil these requirements, as compliance may be difficult to achieve further down the line. High-risk areas – largely in London, although there are some in central Manchester – must adhere to more stringent standards than other parts of England, where there is only a moderate overheating risk.
With the increasing uptake of electric vehicles, the government has also introduced requirements to install charge points in new builds.
Part S requires all new residential and mixed-use buildings – as well as buildings undergoing a material change of use or major renovations – to install charge points for dedicated parking spaces.
There are some exemptions, though. These include a cap on the cost of each charge point to £3,600, and exceptions for enclosed or open-sided car parks, while the government is further investigating fire safety concerns related to charging.
'With the increasing uptake of electric vehicles, the government has also introduced requirements to install charge points in new builds'
Building control surveyors and those conducting the Standard Assessment Procedure (SAP) must produce new Building Regulations England Part L (BREL) compliance reports.
This entails producing both a design-stage BREL report, before building work commences, and an as-built BREL report that shows the new home has been constructed as per the energy-efficient design specifications.
Local building control and SAP assessors also require photographic evidence specific to each dwelling, to document details of the build during construction.
While it is important to get familiar with the interim uplift in standards, the timeframe for ensuring homes are completely ready for net zero is fast approaching. The full technical specification for the Future Homes Standard 2025 is expected to be issued for consultation early next year. Housebuilders will need to look further ahead than the current regulations to ensure new homes are fully future-proofed.