Building to Net Zero: What UK Developers Need to Know in 2026

The short version for 2026: you are still building new homes to the Part L 2021 uplift, roughly 31% less carbon than the 2013 standard, while the Future Homes Standard is being drafted around you. On top of that sits mandatory 10% biodiversity net gain on every major site, low-carbon heating as the sensible default, and a Greater Manchester planning system that wants net zero sooner than Westminster does. You design for all of it now, not later.

The call we take most often now starts the same way. A developer is a few weeks from start on site, the planning conditions have landed, and buried in them is a biodiversity gain plan or an energy statement that was never costed at the design stage.

We sort it out.

But by then the cheapest options have gone, and the fix comes out of margin instead of the appraisal. Net zero in 2026 is less about one big rule and more about a handful of separate requirements that all want dealing with early, together, on the same drawing.

So here is what each of those requirements actually asks of you, and where they stand this year.

What actually changes for new homes under the Future Homes Standard?

The Future Homes Standard aims for new homes that produce roughly 75-80% less carbon than one built to the 2013 rules. In practice that means low-carbon heating, usually an air-source heat pump, a fabric specification tight enough to make that heat pump work, and rooftop solar on most house types. The assessment moves from SAP 10 toward the new Home Energy Model, and the grid carbon factor that model uses has already fallen to about 0.136 kg of CO2 per kWh, down from 0.519 under the old SAP. That single change is why an electric heat pump now scores far better than a gas boiler on paper.

The timing has slipped more than once. As things stand in 2026 the Standard is expected to be published and laid through the year, with a transition period that has new homes meeting it around the end of 2027. Which leaves a gap. You are legally allowed to keep building to the lower Part L 2021 floor until that transition closes, and plenty of consultants will value-engineer a scheme right down to today's minimum to shave a few thousand pounds a plot.

We think that is a false economy on anything completing from late 2027, and we will say so on record. A home built to the 2021 floor and handed over the same month the Standard bites is dated the day it opens. It also carries an energy performance and running-cost story that a buyer or a valuer will read straight away. Designing to the Standard now costs more up front and less over the life of the asset. For a build-to-sell scheme with a two-year programme, that maths is not close.

Do I still have to hit 10% biodiversity net gain?

Yes, and it is not optional. Under the Environment Act 2021, a 10% biodiversity net gain has been mandatory for major developments since 12 February 2024, and for small sites since 2 April 2024. Whatever biodiversity value the site holds before you start, you have to leave it 10% better, and the new or enhanced habitat has to be secured and managed for at least 30 years. That 30-year tail is the part developers underprice. It is a real, long liability, not a one-off planning tick.

Where you deliver that gain is a genuine trade-off, and the right answer depends on the site. On a tight urban infill of a handful of units, buying off-site biodiversity units is often cheaper and simpler than trying to squeeze habitat onto a plot that has none to spare. On a larger scheme with a green edge, on-site habitat usually wins, because it is under your control and it lifts the place people actually buy into. Get an ecologist on the team early, ideally by RIBA Stage 2, so the gain plan shapes the layout rather than fighting it.

What does net zero mean for commercial and rented buildings?

For commercial stock the pressure comes through Minimum Energy Efficiency Standards. Since April 2023 it has been unlawful to keep letting a commercial building rated below EPC E without a registered exemption. The higher targets have moved around a lot: the interim EPC C step once pencilled in for 2027 has been dropped, and in mid-2026 the government confirmed an EPC B requirement for large non-domestic buildings by 2031 instead. If you are building or refurbishing commercial space to hold and let, design to that B rating now. Retrofitting a building twice inside a decade is how you lose the return.

Fit it out for the target you can already see coming.

This is where a net zero brief stops being an architectural conversation and becomes a numbers one. Heat pumps, better glazing, more insulation and on-site generation all carry a capital cost that has to sit inside the appraisal, and a funder increasingly wants to see it modelled before they release money. We build that into the cost plan from the start, and where a lender is involved we cover it in fund monitoring so nobody is surprised at drawdown.

Why is Greater Manchester ahead of the national rules?

Because the city region set its own clock. Greater Manchester is targeting net zero carbon by 2038, twelve years ahead of the national 2050 date, and Places for Everyone, the joint plan adopted in March 2024, carries an expectation that new development moves toward net zero carbon well before national policy forces the issue. If your scheme sits in Stockport, Manchester or any of the nine districts, the local planning bar is often tighter than the Building Regulations floor, and the energy statement your planner asks for reflects that.

Stockport sharpens the point. A large share of the pipeline here is town-centre brownfield and old mill stock, not green-field plots, so the embodied-carbon question moves up the agenda fast. Knocking down a sound Victorian frame and pouring a new one often loses on whole-life carbon compared with keeping the structure and working around it. That is not a heritage argument, it is a carbon one, and it changes how we would approach the same building. Keep the frame, and you keep decades of embodied carbon out of the sums before you have laid a single new brick.

So what would we do if the scheme were ours?

Fabric first, every time. A heat pump is the honest default now, and we will be blunt about the catch: it only performs the way the model promises if the building is airtight and well insulated. We have seen air-permeability tests come back over the design figure more than once, and the fix is always retro-sealing service penetrations near completion, which is the most expensive moment to be doing it. Get the detailing right on the drawing and at first fix, and the test looks after itself.

Then we would pull the whole compliance picture into one place before a spade goes in the ground, because these rules do not queue up politely one after another.

None of this is a reason to slow a scheme down. It is a reason to front-load the thinking, so the energy statement, the biodiversity gain plan and the cost plan are written together rather than bolted on when a planning officer asks. That is the work we do day to day: reading the rules that apply to your specific site, building them into a deliverable programme, and holding the standard on site so the as-built matches the drawing. If you want that handled properly, our construction project management and project monitoring teams do exactly this across the UK and Europe. When you are ready to test a site or a scheme against the 2026 rules, talk to our team and we will tell you where the risks are before they cost you.