Short answer: from 24 March 2027, solar panels are effectively mandatory on new-build homes in England. The Future Homes Standard does not literally say "you must fit solar" — instead it sets carbon and energy targets that a new dwelling can only realistically meet with rooftop PV plus a heat pump. The practical effect is the same: do new builds need solar panels? Yes, in all but a handful of exempt cases.
What the Future Homes Standard actually requires
The Standard, enacted through Part L 2026 of the Building Regulations, requires new homes to produce around 75-80% less carbon than one built to 2013 standards. The deemed-to-satisfy route specifies solar PV covering 40% of the dwelling's ground floor area. For a typical 3-bed semi (42.5 m² ground floor) that is roughly a 3.4 kWp array — about eight panels. There is a transitional period to 24 March 2028 for plots already under construction. See our full breakdown of the 40% PV rule.
When are solar panels NOT mandatory on a new build?
The Approved Document recognises four exemption categories: dwellings where roof orientation, overshading or size make meaningful PV unfeasible; certain flats in tall blocks where the building-attributable PV area is minimal per dwelling; heritage and Conservation Area constraints; and listed-curtilage plots. In each case the developer must document a technical justification — "we didn't want to" is not an exemption. For heritage-sensitive plots, solar roof tiles (BIPV) are usually the compliant route rather than an exemption.
Do solar panels on new builds have to be a certain size?
Yes — the 40% ground-floor-area benchmark is the key figure, and it scales with house size. A 4-bed detached needs roughly 5.2 kWp; a 5-bed executive home around 7.6 kWp. Token "two-panel" systems that some developers fitted under the old rules no longer pass Building Control. Use our how many panels calculator to size any plot, or read the new-build solar overview.
What this means if you're buying a new build
If you reserve a new-build home completing after the deadline, it will come with solar as standard. The questions worth asking your housebuilder are about quality and ownership, not whether solar is included: is it in-roof or on-roof, what kWp, is there a battery, and crucially — do you receive the export (SEG) payments and the MCS certificate? Our guide on who owns the solar on a new build covers this.
The bottom line
Are solar panels mandatory on new builds? From 24 March 2027, effectively yes across England, with Wales and Scotland following equivalent paths. The smart move for developers and self-builders is to design solar in now rather than scramble at the deadline — and fitting it at build phase costs roughly 20-30% less than retrofitting later. Get a fixed-price FHS quote or explore the Future Homes Standard guide.
