The Future Homes Standard (FHS) is expected to come into effect in 2025 and promises to change the way new homes are built, and how their subsequent performance is measured. Some of the finer details are still under consultation, but it’s expected that new homes will need to produce 75-80% less operational carbon emissions than those built under 2013 regulations.
Housebuilders can start preparing now by taking a fabric first approach to projects and finding ways to close the performance gap.
Laying the groundwork
The Building Regulations have already been updated in anticipation of the FHS. Approved Documents F (Ventilation) and L (Conservation of fuel and power) were updated in 2023, introducing new standards for ventilation, minimum energy efficiency performance targets for buildings, stricter airtightness requirements and tighter limiting U-values for new fabric elements.
New requirements such as the Building Regulations England Part L (BREL) report have also been incorporated into Standard Assessment Procedure (SAP) 10.3 to help verify the quality of insulation installations. One proposal under consultation is to replace SAP altogether with a new Home Energy Model to rate the energy efficiency of new homes and demonstrate compliance.
It’s clear that while an overall reduction in energy usage for new homes is the main objective, changing how performance is measured is also a key part of the FHS.
Closing the performance gap
It has long been recognised that the performance gap is one of the industry’s biggest challenges in reducing building emissions. This gap between how homes are designed to perform and how they perform once built needs to be closed to improve occupant comfort, reduce bills and emissions, and maximise the benefits of low and zero carbon (LZC) technology.
One proposed solution to this problem is to award a ‘Future Homes Standard’ brand to housebuilders who performance test their homes post-occupancy. Although this is still under consultation, it does show that the government wants to move the industry towards measuring in-use energy efficiency.
Current statutory guidance uses notional U-values to demonstrate compliance. While U-values are an important indicator of the expected thermal performance, achieving them in reality requires correct installation. Housebuilders will need to start scrutinising insulation’s performance in the context of the real world, particularly the installation experience.
Rigid board insulation, for example, can be particularly challenging as it won’t sit flush against a cavity unless it is perfectly uniform and flat. Boards also need to be precisely cut and taped, all of which can introduce air gaps that compromise thermal and fire safety performance. Mineral wool insulation, on the other hand, is flexible, conforms closely to the cavity, and knits together at the joints, reducing the risk of air gaps and ensuring better overall performance.
Airtightness, ventilation and solar gain also need to be considered to ensure homes meet the FHS.
Enabling LZC technologies
Addressing the performance gap in new homes will also make them ready for LZC technologies. These are likely to be a key part of the FHS, but their exact implementation is yet to be finalised.
LZC technologies depend on a well-insulated building envelope to be effective and deliver savings in emissions. Heat pumps, for example, come in a range of sizes and must be correctly matched to the space they’re heating. If more heat than designed is lost through the building envelope, it effectively increases the size of the space, making the heat pump less efficient and more costly, even if the correct size was specified in the design.
Mechanical Ventilation with Heat Recovery (MVHR) systems also rely on airtight insulation to perform effectively. MVHR provides fresh filtered air into a building whilst retaining most of the energy that has already been used in heating the building.
Housebuilders should take a fabric first approach to provide flexibility on the adoption of LZC technology. An airtight and thermally efficient building fabric will deliver significant energy savings and improve comfort for building occupants, before any new technology is added. Making homes ready for their introduction will give housebuilders and occupants the option to adopt these technologies when they are mandated.
The future is real performance
While some of the detail of the FHS is subject to change, it’s clear that housebuilders will need to start preparing for it now by prioritising the building fabric. Ensuring new homes perform as well in reality as they do on paper will substantially reduce in-use emissions and make the introduction of LZC technologies far more impactful on people’s bills and energy consumption.