The Future Homes and Buildings Standards (FHS) consultation was launched on 13th December 2023 and closes to responses on 6th March 2024. It proposes requirements to ensure all new buildings reduce carbon dioxide emissions and are net zero carbon ready.
The government’s stated aims are to set even more ambitious requirements for energy efficiency and heating of new buildings, ensure no further work is required to those buildings to achieve zero carbon emissions (as the electricity grid decarbonises), to reduce occupant running costs, and to prevent damp, mould, excess cold and heat, and improve air quality.
When will new buildings have to comply with the new standards?
The government intend to lay the new regulations and technical standards in 2024. It is seeking views on whether to provide a 6 or 12-month period before the legislation then comes into force. Once in force, there will be a further 12 months transitional period for buildings registered under Part L 2021.
If work has not commenced on an individual building by the end of this period, it will be subject to the new requirements. Note that the definition of commencement is proposed to be updated to align with the Building Safety Act 2022.
What are the proposed changes?
It is proposed to assess new homes against the same three performance metrics applied under Part L 2021 (emissions, fabric energy efficiency and primary energy).
Two options are proposed for a concurrent notional building which will set the target performance for these metrics, meaning developers will retain design flexibility on how to demonstrate compliance (subject to a range of minimum standards and backstops).
Compliance will be assessed using a new model called the Home Energy Model. This will replace SAP and represents a major change, including more dynamic assessment of energy demands and the use of half-hourly local weather data in place of monthly data at a national level.
Notional Building Specifications
The consultation seeks views on two options for the notional building:
- Option 1: No improvement to fabric over Part L 2021, also retaining waste water heat recovery and solar PV. Lower air permeability and DMEV ventilation are new requirements, with an efficient air source heat pump replacing gas boiler as the main heat source.
- Option 2: As per Option 1, but with relaxed air permeability and ventilation (in line with Part L 2021) and no requirement for solar PV or waste water heat recovery.
In addition to the above core options, certain dwellings will be subject to alternative notional building comparisons. This includes those in buildings over 15 storeys and those created through a material change of use.
Dwellings connecting to heat networks or communal heating systems will be compared to a notional building including a heat network power by highly efficient air source heat pumps with very low heat losses. Provisions are proposed to enable dwellings to connect to existing, gas fired heat networks, provided low carbon plant is installed on that network with capacity to supply the new dwelling (see our previous article on Sleeving which outlines this concept).
The use of gas boilers is not envisaged to be possible as a route to compliance with the new standard and the consultation documents specifically state that hydrogen-ready boilers are also not anticipated to comply.
What is the likely impact on build costs?
A comprehensive Impact Assessment accompanies the consultation, but it predicts that the cost uplift for a small semi-detached home will be £6,200 (Option 1) or £1,000 (Option 2) compared to Part L 2021 compliant construction costs.
What is the likely impact on occupant running costs?
The consultation states that both options will achieve running cost savings compared to a typical existing home. More controversially, it predicts that a home built to achieve compliance with Option 2 will result in annual fuel bills for heating and hot water of approximately £600/yr more than one built to the Part L 2021 standard.
What about Part O?
There are no proposals to change or update Part O within the consultation, but it seeks views on the implementation of Part O and the potential to extend its requirements to homes created through a material change of use.