The 2022 building regulations are the tightest energy standards the UK has ever set for new homes and major renovations. From 15 June 2022, every new dwelling and most extensions must cut carbon emissions by 30% compared with the 2013 baseline, a shift that rewrites the rulebook for architects, builders, and homeowners alike.
As reported by The Architects’ Journal, the changes cover three key documents: Part L (conservation of fuel and power), Part F (ventilation), and the new Part O (overheating). For homeowners, the immediate effect is on cost and compliance when building an extension, converting a loft, or replacing windows.
What the new rules demand
Part L now requires fabric-first efficiency: walls, roofs, and floors must achieve U-values of 0.15–0.18 W/m²K, roughly 20% better than before. Windows must hit 1.2 W/m²K or lower, triple glazing is increasingly standard. Heating systems must be low-carbon: gas boilers are still allowed but only if the fabric is so efficient that the heat loss calculation stays below a new ‘target emission rate’. In practice, many new homes and larger extensions now specify heat pumps.
Part F mandates mechanical ventilation with heat recovery (MVHR) in any dwelling with an air permeability below 5 m³/h·m² at 50 Pa, which most new builds and deep retrofits now achieve. Part O, meanwhile, limits glazing area to 25% of floor space in south-facing rooms to prevent summer overheating, a growing concern as UK summers hit 40°C.
What it costs a typical 3-bed semi
A 25 m² single-storey extension under the 2022 regs costs roughly £45,000–£55,000, up from £35,000–£45,000 under the old rules, according to industry estimates. The extra £10,000 comes from triple glazing (£2,500), improved wall and floor insulation (£3,000), and an MVHR unit (£4,500 installed). But the running cost drops: a gas-heated extension now uses 2,500–3,000 kWh per year versus 4,000–5,000 kWh under 2013 regs. At current price caps (24.5p/kWh electricity, 6.24p/kWh gas), that’s a saving of £150–£300 annually on heating alone.
For a full new-build home (say a 100 m² three-bed), the fabric improvements add £8,000–£12,000 to build cost but cut the annual heating bill from £900 to £550. The EPC rating jumps from a typical C to an A or B, adding an estimated £10,000–£15,000 to resale value, per Nationwide’s 2023 research on EPC premiums.
Who pays, and who benefits
But the rules don’t apply retrospectively. If you’re not building or extending, nothing changes. The catch is that replacement windows and boilers must meet the new standards: a gas boiler fitted after June 2022 must be at least 92% efficient (most are), and replacement glazing must achieve 1.4 W/m²K or lower. That means homeowners replacing old single glazing with double glazing now need argon-filled, low-E coated units, a 10–15% premium over basic double glazing, but a 20% reduction in heat loss.
Ofgem’s latest data shows that homes built to 2022 regs use 35–40% less gas than those built to 2006 standards. The Energy Saving Trust calculates that a typical 2022-compliant home saves 2.5 tonnes of CO2 per year versus a 2013 build. For the homeowner, that translates into a lower energy bill and a higher EPC, but only if you’re building new or doing major work.
What you should do now
If you’re planning an extension or loft conversion in the next 12 months, commission a SAP (Standard Assessment Procedure) calculation early, your architect or builder needs it to prove compliance. Budget for the extra £3,000–£6,000. If you’re replacing windows, ask for a ‘Part L compliant’ certificate from the installer, it’s now a legal requirement under Building Regulations. And if you’re buying a new-build home, check the EPC rating: it should be B or above, and the developer must provide a ‘design-stage’ SAP rating before you exchange contracts.
The 2022 regs are not optional. They are the single biggest regulatory push toward net-zero housing in a generation. Ignore them, and your extension won’t get signed off, your windows won’t meet warranty conditions, and your home will burn more cash every winter. The deadline for compliance is the day you start work, not the day you finish.
Frequently Asked Questions
No, they apply only to new builds and 'materially altered' parts of existing homes, such as extensions, loft conversions, or replacement windows. If you're just redecorating or replacing a boiler like-for-like, the old standards still apply. But any new work must meet the 2022 targets.
No. Gas boilers are still permitted in new builds and extensions under Part L, provided the building fabric is efficient enough to meet the target emission rate. However, from 2025, the Future Homes Standard will effectively ban gas boilers in new homes. For existing homes, there is no boiler ban, only a requirement to fit efficient models when replacing.
