Accompanied by much excitement in the solar industry, the Future Homes Standard (FHS) consultation response was finally published on 24th March 2026, and little wonder because the new regulations make renewable electricity generation (solar PV) mandatory on nearly all new homes. But how long will it take for the new regulations to feed through into bricks and mortar on the ground, and more importantly solar panels on the roof?
The transitional arrangements published alongside the new regulations give developers some breathing room to get themselves ready to deliver the new specification at scale. The rules come into force in 12 months. From March 24th 2027, any new development that applies to Building Control for approval will see all homes on that site built to the new regulations.
A second deadline follows in March 2028. After this, all homes not yet "commenced" will need to be meet the FHS, irrespective of when the Building Control application was lodged.
The transitional arrangements are identical to those that applied to the last update to the building regulations for energy efficiency - Part L 2021. So we can use the last building regulations transition as a model for the next.
What Went Before - Part L 2021
Part L 2021 was announced in that year, with a start date of July 2022 for new sites and July 2023 for houses not yet commenced. The graph at the top shows the number of housing starts in England (black line) and completions (blue line) from 2018 to 2025.
The solid orange line shows the number of housing completions that were built to Part L 2021. This data is provided by the Future Homes Hub and inferred from the software version used to generate the Energy Performance Certificates for the homes. The dotted orange line is shifted three months as an estimate for roofing works going on, and solar panels being installed.
In December 2025, only 60% of homes that completed in England were built to Part L 2021 - some three and a half years after the regulations came into force. How is this possible?
The clue to the answer to this question is found by looking at the black line. There was an unusual spike in housing starts in the run up to the June 2023 cut-over date. Housebuilders commenced nearly 30,000 more houses than in a normal quarter. Strip foundations were excavated and concrete poured to classify plots as commenced. These foundations were then mothballed for many, many months before being built on later - and locking in the older, and lower cost regulations.
What This Means for the FHS
The FHS imposes higher costs on developers, around £5,000 per house according to the Government's own Impact Assessment, so the incentive to delay the change over will definitely be there, just as it was for Part L 2021.
There are a couple of potentially important differences this time around which may influence how long the transition takes.
Firstly, the 2023 rush to lay foundations and beat the deadline for commencement occurred as mortgage rate increases precipitated a house buyers' strike. The foundations lasted longer than they would have if the housebuilders were working at their usual rates.
Secondly, what counts as a "commencement" changed in late 2023 and now requires the first floor structure to be complete. So for a house with a concrete slab ground floor, to the cost of the foundation you can now add the cost of building the below ground walls, a base-layer of hardcore and blinding and then pouring a concrete slab, plus all the drainage and service ducts required.
Will this second change be enough to change the financial calculations of the housebuilders - it's too early to say, but given the size of the prize from the cost saving, it's hard to see why the housebuilders won't rinse and repeat what they did for the 2021 regulations.
A sober assessment of how quickly the FHS will feed though to demand for more solar PV puts the start of the ramp in June 2028 and runs through to the end of 2030.
