The UK government confirmed in March 2026 that the Future Homes Standard (FHS) will come into force on 24 March 2027, with full compliance required by March 2028. For small developers and construction startups, that's a tight window. Every new home will need low-carbon heating, mandatory solar panels, and improved insulation.
Gas boilers won't meet the new carbon targets, and there's no wiggle room once the transition period ends. Continue reading to see what's changing and how it'll affect anyone building homes in the UK.
Why Gas Boilers Are Being Phased Out in New Builds
The FHS requires new homes to produce at least 75% less carbon than those built to 2013 standards. Gas boilers simply can't hit that number. The government hasn't used the word ban in the legislation, but the carbon targets are set at a level that rules out fossil fuel heating entirely.
Heat pumps, primarily air source and ground source, will become the default. Hybrid systems and hydrogen-ready boilers won't comply either. For builders who've spent decades speccing gas combi boilers into every plot, this is a fundamental change in how homes are designed from the ground up.
Existing Homes Are a Different Story
It's important to point out that the FHS only applies to new builds. For the millions of existing homes across the UK, gas boilers remain perfectly legal and are still the most common heating system by a wide margin. Homeowners looking to replace an old or broken boiler today can still choose iHeat boilers as a reliable and readily available option for upgrading their heating systems.
The government has scrapped the previously proposed 2035 deadline for phasing gas boilers out of existing properties altogether. Instead, it's relying on voluntary adoption of low-carbon alternatives, supported by incentives like the Boiler Upgrade Scheme, which offers up to £7,500 towards a heat pump installation.
So while the direction of travel is clearly towards electrification, homeowners aren't under the same immediate pressure as developers. For now, upgrading to a modern, efficient gas boiler is still a practical and cost-effective choice for most households.
What Small Developers Need to Budget For
The government's own impact assessment estimates an additional build cost of around £4,350 per dwelling. That covers heat pumps, solar PV, better insulation, and mechanical ventilation. For a small developer working on a 10-unit scheme, that's an extra £43,500 before you've even factored in the learning curve.
There are also knock-on costs that don't always show up in headline figures:
- Training or hiring installers with heat pump experience
- Longer design phases to meet the new Home Energy Model (HEM) compliance tool
- Potential grid connection delays as local networks handle more solar export
- Sourcing solar panels equivalent to 40% of each dwelling's ground floor area
It's worth noting that the HEM replaces the old SAP calculations. Builders who are familiar with SAP will need to get up to speed on a different compliance methodology before 2027.
How Solar Panels Will Change Roof Design
Under the FHS, solar PV is no longer optional. New homes will need panels covering the equivalent of 40% of the building's ground floor area. For a typical three-bedroom house, that works out at roughly a 4-5 kWp system, or around 8-10 panels.
This has real consequences for how roofs are designed. South and west-facing elevations will carry more weight in planning decisions, and the new HEM uses half-hourly solar modelling. That means orientation, pitch, and shading all matter more than they used to. Developers who treat solar as an afterthought will struggle with compliance.
Buildings over 18 metres are exempt, and there are allowances for sites where a 720 kWh/year output can't be achieved. But for the vast majority of low-rise housing, solar is now a baseline requirement.
Closing Up
The Future Homes Standard is the biggest change to UK building regulations in years. If you're a small developer or construction startup, the time to prepare is now. Get familiar with the Home Energy Model, start talking to heat pump and solar suppliers, and factor the extra costs into your project budgets early. The 12-month transition period will go faster than you think.
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