After years of “it’s coming, honest,” the Future Homes and Buildings Standards are no longer a rumour. On 24 March 2026, MHCLG published the new statutory guidance — Approved Document L 2026 (Volumes 1 and 2) plus an updated Approved Document F — alongside The Building Regulations etc. (Amendment) (England) Regulations 2026.
The dates that matter
The headline you need to diarise: the changes come into force on 24 March 2027. There’s a one-year buffer too — for non-HRB work, projects with a building notice, initial notice or full-plans application submitted before 24 March 2027 can still build to current standards, provided work starts before 24 March 2028. Higher-risk buildings get a slightly later switch-on of 24 September 2027 with their own transitional rules.
In short: you’ve got runway, but the clock is now genuinely ticking. (Building Circular 01/2026, gov.uk)
What’s new in the rules
The big-ticket changes amend the Building Regulations 2010 to bake in low-carbon heating and high-efficiency fabric, so new homes won’t need retrofitting to hit zero-carbon-in-use as the grid decarbonises. Notable bits:
- A new functional requirement (L3) mandating on-site renewable electricity generation (think solar PV) for new dwellings and buildings containing dwellings.
- Part L of Schedule 1 reworded to cover both cutting greenhouse gas emissions and conserving energy.
- “Fixed building services” widened to include lifts, escalators and moving footways in non-dwelling buildings.
- A new regulation 40C requiring homeowner information (the Home User Guide) in a usable format.
And — importantly for the carbon maths — the old 2013 and 2021 transitional arrangements that let people keep building to 2010 energy standards are being revoked.
What about SAP and the Home Energy Model?
One thing that trips people up: at launch, SAP 10.3 is the only methodology you can use to demonstrate compliance. The much-discussed Home Energy Model (HEM) isn’t the approved tool on day one — it follows a minimum of three months after the standard goes live, with a confirmed dual-running period before it eventually replaces SAP. So for now, plan around SAP 10.3.
What this means for you (and your junctions)
Here’s the bit competitors gloss over. Tighter fabric standards make thermal bridging matter more, not less. As walls, roofs and floors get better insulated, the heat that sneaks out through poorly-detailed junctions becomes a bigger slice of the total loss. Lean on the default junction Psi-value of 0.15 W/m·K and you’ll be carrying a hefty, avoidable penalty in your calculation.
The fix is the same as it’s always been, just higher-stakes: calculate your junction Psi-values properly to BS EN ISO 10211, following BR 497 conventions, rather than accepting worst-case defaults. Get the details right on paper and your SAP figures breathe a lot easier.
That’s exactly what ΨMonkey is for — a browser-based Psi-value calculator that does ISO 10211 thermal modelling without the stuffy desktop software or the eye-watering consultancy invoice. Model your junctions, drop the real numbers into your assessment, and give the Future Homes Standard the respect it deserves (while not taking the paperwork too seriously).
Sources: Building Circular 01/2026 (gov.uk) · Approved Document L Volume 1 2026 (gov.uk) · The Building Regulations etc. (Amendment) (England) Regulations 2026 (legislation.gov.uk)