What This Requirement Covers
The Future Homes Standard (FHS) is the next major update to Part L of the Building Regulations for new dwellings in England. Originally planned for 2025, it will require new homes to produce significantly less carbon than current standards. The 2021 Part L was designed as an interim stepping stone towards the FHS.
Key Requirements
Carbon Reduction Target
- New homes must produce 75-80% less carbon than the 2013 Part L baseline
- This effectively mandates low-carbon heating (the target cannot be met with a gas boiler, even with high fabric efficiency and solar PV)
- The carbon metric will shift towards primary energy as the key compliance measure
Heating Systems
- Heat pumps (air source or ground source) are expected to be the primary heating system for FHS compliance
- Hydrogen-ready boilers may be permitted as a transitional measure in areas designated for hydrogen conversion, though this remains uncertain
- Direct electric heating may comply in very well-insulated dwellings but is unlikely to be cost-effective
- Gas boilers will not meet the carbon emission target under the FHS
Fabric Performance
Expected fabric standards (subject to final consultation)
- External walls: 0.15-0.18 W/m²K (improved from 0.26 W/m²K under 2021 Part L)
- Floors: 0.11-0.15 W/m²K
- Roofs: 0.11-0.13 W/m²K
- Windows: 0.8-1.2 W/m²K (triple glazing likely to become standard)
- Air permeability: 5 m³/(h.m²) or better (tighter than the current 8 m³/(h.m²))
Ventilation
- MVHR (Mechanical Ventilation with Heat Recovery) is expected to become the standard ventilation system for FHS homes, given the tighter air permeability targets
- Heat recovery efficiency of 90%+ will be needed to support the overall energy performance
Overheating
- The FHS is expected to be accompanied by a new Part O (Overheating) requirement (already introduced in 2021)
- Homes must be designed to avoid overheating during summer, considering orientation, glazing ratios, shading, and ventilation
Practical Compliance Tips
- Start designing heat pump-ready homes now; the transition from gas boilers requires changes to radiator sizing, hot water provision, and electrical supply
- Invest in fabric efficiency above the current minimum; the cost of upgrading later is much higher
- Specify triple glazing and MVHR as standard in new developments to prepare for the FHS
- Consider the impact of the FHS on development viability; higher build costs will need to be factored into land values and sales prices
- Engage with SAP assessors and energy consultants to model FHS compliance scenarios for current projects
- Monitor Government publications for the final FHS specifications; details may change from the consultation proposals
- Plan for the Future Buildings Standard (the equivalent update for non-domestic buildings) which is expected to follow