Guide: The Future Homes Standard
The Future Homes Standard (FHS) is the latest update to Building Regulations in England. Despite its name, it does not create a new approval route or radically transform housing; it simply sets clearer targets for energy efficiency, low running costs, and future-proofed, low-carbon-ready homes.
Part L remains the legal framework for energy performance. The FHS is the update to Parts L & F, introducing stricter rules for insulation, heating, ventilation, and energy use. The timeline overview is as follows:
2025/26: The FHS will be formally published.
From 2027: All new-build homes must comply with the full standard
U Values
The elemental benchmark U values have increased. When they come info effect they will be as follows:
Walls: around 0.15 W/m²K
Roofs: 0.11–0.12 W/m²K
Floors: 0.10–0.12 W/m²K
Windows: 0.8–1.0 W/m²K
At Paul Ashton Architects, we have already been designing houses with these levels of insulation for many years. The FHS formalises the direction we were already working in.
In our opinion the most immediate impact of FHS on-site will be the new elemental benchmark for window U-values. To meet the target of 0.8–1.0 W/m²K, most new homes will now need triple glazing. This not only reduces heat loss and enhances comfort but also supports low-carbon heating systems. We have specified triple glazing for many years so this update aligns with our existing approach but this move will increase costs for even simple builds.
Airtightness: a big step up
Under FHS, new homes must achieve an air permeability of 3 m³/m²·h at 50 Pa or better, compared with the 2022 Part L limit of 5 m³/m²·h. Even small gaps around windows, sockets, or eaves can degrade air tightness so close attention to these junction will become more important than ever. As a result, most new homes aiming to fully meet FHS performance will require some form of mechanical ventilation. In practice, this usually means MVHR systems, which improve indoor air quality and recover heat, but they also add to the overall build cost.
Heating
Under the proposed Future Homes Standard, new homes are expected to adopt low‑carbon heating systems rather than fossil‑fuel gas boilers, although final regulatory details remain subject to change.
Why it matters on-site
For small developers and self-builders, the key points are practical:
SAP modelling must be done early
Insulation must be fitted neatly and continuously with overlaps where applicable
Airtightness must be planned, not guessed
High-performance windows and doors are essential
Ventilation systems require correct commissioning
Conclusion
The Future Homes Standard raises the bar, but it is not a dramatic change for those already aiming for high-quality construction. At Paul Ashton Architects, our designs already use triple glazing, low U-values, and airtight construction. The FHS simply formalises the direction we were already taking: thoughtful detailing, energy-efficient materials, and homes that are comfortable, future-ready, and low-carbon.
