The Future Homes Standard has been published. For house builders and developers, the most pressing question is not what the standard requires. It’s when it actually applies to you.
Here is a practical breakdown of the confirmed implementation timeline and what it means for projects at every stage.
The headline date: 24 March 2027
The Future Homes Standard comes into force on 24 March 2027 for non-higher-risk-building dwellings. Higher-risk buildings follow on 24 September 2027. From these dates, all new homes must comply with updated building regulations, mandating low-carbon heating (in practice, heat pumps), on-site renewable electricity generation (in practice, rooftop solar PV), and dramatically tighter fabric and ventilation standards.
The transitional period: 12 months, no extensions
The published standard confirms a 12-month transition period. Building work must have commenced by 24 March 2028 to use current Part L regulations. After that date, every new dwelling must comply with the FHS.
Key details from the published transitional arrangements:
- “Commenced” means real construction activity. Drainage and foundation work qualifies. Planning permission alone does not.
- Individual building basis. Different homes on the same site may fall under different regulations depending on when each building’s work commenced. There is no site-wide exemption.
- 2013 transitional arrangements are sunsetted. No further extensions to legacy provisions.
- No Regulation 26 relaxation. The government considered allowing developers to argue compliance was “not reasonable” on certain sites. They rejected this. There is no escape route.
The transitional provisions operate per dwelling, not per phase or per site. Developers need to track commencement dates at individual building level.
What the standard requires
The published FHS introduces six headline requirements: mandatory on-site renewable electricity generation (in practice, solar PV, now a functional requirement not tradeable against other measures), a 75-80% carbon reduction target vs 2013 baseline, low-carbon heating only (gas boilers cannot comply), tighter fabric U-values across every building element, airtightness of 3 m³/(h·m²) requiring MVHR, and individual dwelling compliance with no terrace averaging.
Notably absent: battery storage, smart export capability, and any assessment of unregulated energy demand. The standard mandates on-site renewable generation but not storage, despite the new compliance methodology (HEM) directly rewarding self-consumption through 30-minute interval modelling.
The HEM transition: a parallel timeline
The compliance methodology transition is now confirmed with specific milestones:
- At FHS launch (March 2027): SAP 10.3 is the sole compliance methodology. SAP 10.3 replaces SAP 10.2 and uses the updated panel efficiency factor but does not granularly model self-consumption.
- Three months or more after launch: The Home Energy Model (HEM) becomes available via the ECaaS platform, a centralised cloud API replacing multiple third-party SAP engines.
- Minimum 24-month dual running: SAP 10.3 and HEM run in parallel. SAP 10.3’s minimum lifetime expires around mid-2029, at which point HEM is expected to become the sole methodology.
HEM models energy at 30-minute intervals. This fundamentally changes how solar generation, self-consumption and battery storage are valued. Solar matched against actual demand profiles throughout the day is worth significantly more than flat annual yield calculations. HEM assessments take approximately 1 hour 40 minutes per dwelling (vs ~20 minutes for SAP), and missing data triggers punitive default values.
What developers should do right now
The 2027 deadline sounds distant. It is not. Here is why:
Design lead times. A development that starts on site in March 2027 is being designed today. Retrofitting solar, heat pump and MVHR systems into designs not conceived for them is costly and sometimes impossible. The airtightness target of 3 m³/(h·m²) requires ducting integrated from design stage.
Cost planning. The published standard confirms an estimated 3-5% additional build cost over current Part L compliance. For a typical £250k-£350k new build, that is £7,500-£17,500 per dwelling. Solar PV alone represents £5,000-£10,000 per plot. Innovative solutions need to be sought to minimise these costs. For solar, Gryd can eliminate this additional cost burden.
Supply chain. Heat pump, solar and MVHR installation capacity is finite. Developers who secure supply chain relationships now will have an advantage over those competing for capacity in late 2028.
Planning. If you have sites where planning has not been submitted, designing to FHS from the outset avoids costly revisions later and demonstrates ESG commitment increasingly valued by planning authorities.
Compliance expertise. HEM is more complex than SAP. Energy consultants will need time to build capability on the new methodology. Developers who engage early will get better advice and avoid bottlenecks.
The bottom line
The FHS is published. 24 March 2027 is the statutory deadline. 24 March 2028 is the last date to commence building work under current regulations. There are no exemptions, no averaging and no escape routes.
Developers who treat this as a compliance event will meet the minimum. Those who treat it as a design and commercial opportunity will build better homes and stronger businesses.
