The Future Homes Standard (Part L 2026) is now law, and it changes how every new home in England gets designed from 24 March 2027. New homes must cut carbon by at least 75% against 2013 standards, solar panels become a legal requirement under new Requirement L3, and the transition now runs plot by plot. Miss the transition rules on your live plots and you could be redesigning under a method that scores your homes differently.
Jump to a chapter in the video:
- 0:00 What the Future Homes Standard means in fifteen seconds
- 0:28 The developer loophole that just got banned
- 1:15 Designing around the heat pump
- 2:27 Solar panels are now a Building Regulation
- 3:20 SAP to HEM transition
- 4:28 What's coming next
What you'll learn
✔ The confirmed dates for the Future Homes Standard and the transitional deadlines that follow
✔ Why the old loophole for phasing a whole site under old rules no longer applies
✔ How heat pump led design changes your floor plans, cylinder space and emitter sizing
✔ Why Requirement L3 makes solar panels a legal requirement, not an optional extra
✔ What the move from SAP 10.3 to the Home Energy Model means for your energy assessments
When does the Future Homes Standard come into force?
The Future Homes Standard comes into force on 24 March 2027 in England, followed by a 12-month transitional period ending 24 March 2028. It requires new homes to cut carbon emissions by at least 75% against 2013 standards, which in practice means a heat pump and solar panels in most new homes.
The standard was published on 24 March 2026 through amendments to the Building Regulations 2010, alongside the new Approved Document L 2026 and the government's Future Homes and Buildings Standards consultation response. Solar panels are now part of the Building Regulations, and the calculation method everyone currently uses will eventually be switched off. Here are the four things to get right, starting with the most urgent.
Which plots must meet the Future Homes Standard? The transition is now per plot
Any individual plot not started by 24 March 2028 must meet the full Future Homes Standard, even if the plot next door broke ground years earlier. The old site-wide transition, where starting one plot locked in the old rules for the whole site, has been banned.
Under every previous Part L uplift, a developer could start one plot and build out the whole site to the old rules, sometimes for years. That loophole is gone. The consultation response also sunsets the older transitional arrangements, so plots still relying on transition rules from previous uplifts are caught too.
If you're holding consented plots designed to the 2021 rules, audit the programme now, plot by plot. Everything that won't be started by March 2028 needs respecifying. That audit is the cheapest compliance work you'll do all year.
Are gas boilers banned under the Future Homes Standard?
Gas boilers aren't banned by name, but the carbon targets are set so that no fossil fuel heating system can pass compliance in a new dwelling. Heat pumps become the default heating system for new homes from March 2027, so design around one from concept stage.
Here's the bit that catches people out. The heat pump isn't the problem. It's what it does to your floor plans. Heat pumps need a hot water cylinder, and that cylinder needs floor space. If your standard house types don't allow for one, that's a layout revision, and it's far cheaper to resolve at concept stage than at technical design.
Heat pumps also run at lower flow temperatures than gas-fired systems, which means the building's heat demand carries real weight in the compliance model. Emitter sizing and fabric detailing that a gas boiler would comfortably absorb can now be the difference between a pass and a fail.
One piece of good news: the new calculation uses updated grid carbon factors, so heat pumps finally score on paper closer to how they perform in reality.
How much solar do new homes need under Requirement L3?
New homes need solar panels covering the equivalent of at least 40% of the dwelling's ground floor area, calculated at a panel efficiency of 0.22 kWp per m². Requirement L3 makes on-site renewable electricity a functional requirement of the Building Regulations for the first time.
The sizing route for houses is set out in Approved Document L1, paragraph 5.73, with a separate provision for flats. A worked example: a house with a 50 m² ground floor needs at least 20 m² of panels, which at 0.22 kWp per m² means a system of around 4.4 kWp.
There are no automatic exemptions for heavy shading, poor orientation or an awkward roof. Where 40% genuinely can't be met, a reasonable amount must be installed and evidenced in the compliance file rather than simply waived.
Your roof is now a compliance document. Pitch, orientation, dormers and roof lights all eat into the available solar area. Sort the roof layout at concept stage, not once the roof is already detailed.
What replaces SAP? The move to the Home Energy Model
At launch on 24 March 2027, SAP 10.3 is the only approved compliance method. The Home Energy Model (HEM) follows once approved, running alongside SAP 10.3 for a minimum of 24 months before SAP is retired. The exact retirement date is still tbc, but the direction is clear: the industry moves to HEM over the next two to three years.
HEM simulates a building at half-hourly intervals, 17,520 calculation timesteps a year, rather than the monthly averages SAP has used for years. It runs through a cloud-based calculation engine (an ECaaS setup, which we've covered separately in our ECaaS article). That extra detail means as-built quality matters more. Gaps between what's drawn and what's actually built will show up in the numbers.
If your plots complete over the next few years, your energy assessment will likely straddle both methods. Make sure whoever's running your SAPs is also ready for HEM, or you risk a mid-project change of assessor, or a redesign under a method that scores the home differently. For the fuller timeline, see our article on the SAP to HEM transition and Part L 2026.
What's coming next after the Future Homes Standard?
The government's consultation response confirms a full technical review of Part O overheating, including consideration of the updated CIBSE TM59, and a further consultation covering existing buildings is expected, timing tbc.
This isn't the end of the changes. At Energy Digest, we're already running Future Homes Standard specs on live schemes.
Frequently asked questions
When was the Future Homes Standard published? The final Approved Documents and the government's consultation response were published by MHCLG on 24 March 2026, with the regulations coming into force exactly 12 months later on 24 March 2027.
Does the Future Homes Standard apply to existing homes? No. It applies to new dwellings in England. A separate consultation covering existing buildings is expected, timing tbc, and a further consultation on the compliance method for conversions has also been signalled.
Can I still use a gas boiler in a new build after March 2027? In practice, no. Fossil fuel systems cannot meet the new carbon targets for new dwellings, so compliance requires low carbon heating, which for most homes means a heat pump.
What happens to plots designed under Part L 2021? Each plot must make a meaningful start before 24 March 2028 to complete under the 2021 rules. Any plot not started by that date must be redesigned to the full Future Homes Standard, regardless of when the wider site began.
Do flats need the same solar coverage as houses? No. Houses follow the 40% of ground floor area rule in paragraph 5.73 of Approved Document L1. Flats have a separate, lower provision reflecting shared roof space. Check the relevant paragraph for your building type before sizing the array.
Get your specification checked before it's fixed
At Energy Digest we help architects, developers and self-builders get their schemes ready for the Future Homes Standard across the UK. Our services include:
- SAP calculations
- Part L compliance checks
- Energy statements
- Part O overheating assessments
- TM59 dynamic thermal modelling
- Level 5 SBEM with Dynamic Simulation Modelling
- Condensation risk analysis (Glaser Method)
Fixed pricing on most projects, a reliable turnaround, and free phone and email support before you commit to anything.
If your project lands anywhere near March 2027, get in touch before the design is fixed. A five-minute conversation now beats a five-figure redesign later.
