How New Energy Rules Are Changing the Way We Build
The UK government wants every new building to play its part in cutting carbon emissions. This means changing how we build, heat, and insulate our homes and offices. To do this, the government has made big updates to the Building Regulations, especially Part L, which deals with the use of fuel and power.
These updated rules don’t just aim to improve energy savings. They’re a step towards making our buildings “net zero ready” by 2025. Builders and developers must act fast to meet these new rules and avoid costly delays or penalties.
Understanding Building Regulations Part L
Part L of the Building Regulations sets the legal standards for energy performance. It covers both new builds and changes to existing properties. The main goal is to use less energy and reduce the amount of carbon dioxide that buildings release.
Part L is broken into different sections:
- Part L1A: New homes
- Part L1B: Refurbished or extended homes
- Part L2A: New non-residential buildings
- Part L2B: Refurbished or extended non-residential buildings
In 2022, the government raised the bar by introducing a rule that new homes must emit 31% less carbon than before. This is one of the major stepping stones towards the Future Homes Standard, which kicks in from 2025.
One other big change is swapping the old SAP calculation with the Home Energy Model (HEM). This new method offers better detail and accuracy in predicting how a home will perform. It’s designed to help us build homes that live up to the promise of a low-carbon future.
At Ratio Seven, we know how much impact these changes are having on the construction world. Whether you’re planning a housing estate or a single timber frame build, getting your calculations right is more vital than ever.
How To Get Part L Compliant Fast
You don’t have time on your side if you’re a construction professional. Part L compliance is not something to leave to the last minute.
Here’s how we recommend speeding things up:
- Stay up to date. The Ratio Seven blog is packed with up-to-date guidance on energy rules and compliance strategies.
- Work with the right people. An experienced energy assessor can help you run detailed energy models early in your project. This limits the risk of mistakes that need fixing later.
- Train your teams on the key elements, such as installing low-carbon tech like MVHR systems, modern insulation, and heat pumps. We’ve seen many builders fall behind just because they weren’t trained on how to meet new standards.
- Adopt smarter systems now. By getting ahead of the curve and installing systems required for 2025 now, you will save time and costs later.
- Do your testing. Airtightness tests, thermal imaging, and updated assessments using SAP or the Home Energy Model must be handled with care.
If you’re wondering how this works in areas like home extensions, you need to know that any major refurbishment also falls under the newer version of the rules. That’s why this comparison of development rules in Cheshire East and Wigan shows how planning decisions and energy compliance go hand-in-hand.
Lastly, be aware of smaller but stubborn compliance items. In every heated room, a thermostatic radiator valve (TRV) is now mandatory unless that room already has a thermostat. Ignoring this could mean a failed inspection.
Building Regulations Part L: Getting Your Paperwork Right
The rules now say: if it’s not photographed, it didn’t happen. That might sound harsh, but the building control teams want to see exactly how your build meets energy rules.
What’s needed:
- High-quality, digital photos of stages like insulation being laid, seals going in, and before you cover pipework and electrical runs. Cameras need to be geotagged and photos labelled clearly with the plot number and stage.
- Submit a BREL report. This is your official Building Regulations Part L checklist. Without this, you won’t get signed off.
All of this means more pressure. But it’s not just on the contractors. Architects, designers, investors, and planners also need to understand these duties. Fixing things later is harder and slower.
For a full walkthrough on what’s needed, our guide to building control compliance helps break it down with real examples.
Key Technical Requirements for Part L Compliance
These are the top features your project must meet to comply:
- Air tightness: Less heat loss equals less heating needed. Part L 2022 raised the standards again.
- Ventilation: This links to Part F and is about balancing fresh air and heat retention. Systems like MVHR achieve this.
- Insulation: The type and thickness need to meet or beat new U-value targets.
- Heating systems: Gas boilers are still allowed, but only high-efficiency models. Low-carbon systems like heat pumps will help you hit future targets.
- Primary energy metrics: This new rule considers not just how much energy a home uses, but where that energy comes from and how much is lost through supply. It adds a new layer of analysis.
You can prove compliance in two ways:
- Use the Approved Document L guidelines.
- Conduct your energy modelling, with support from accredited professionals, especially helpful for complex or unusual builds.
We also suggest looking into BREEAM assessments, which include Part L within a broader scoring framework if you’re aiming for sustainable credentials.
Why Documentation and Speed Matter
The biggest risk in today’s construction world is delay. Delayed approvals. Delayed completions. That all eats into budgets, and for developers, it often means lowered profit margins.
Failing to meet Part L compliance now can do more than slow you down. You could be hit by fines or asked to rebuild or redesign parts of your project. We’ve helped many builders avoid that by getting involved early.
Whether you build with brick or prefer the benefits of timber frame homes, it all comes back to good documentation and planning.
Whether your project is in the Cotswolds or Birmingham, airtightness testing and digital energy models are your ticket to faster completions.
Building Regulations Part L and the Road Ahead
The current changes are a warm-up for 2025’s Future Homes Standard. Those requirements go even further towards zero-carbon housing and tighter energy targets.
What we’re seeing across the country is that builders who prepare now are winning more projects. Not just by meeting the regulations, but by exceeding buyer expectations for warm, cheaper-to-run homes.
Stay prepared by:
- Adopting new technologies early.
- Running early cost comparisons and including up-to-date energy figures. Our builder’s guide to new build costs can help you plan.
- Knowing who is responsible for what. Everyone, from contractors to designers, plays a role.
- Understanding how energy rules fit with your long-term goals. If you’re building your own dream home, be sure to check our guide to the advantages of self-builds.
FAQs
What does Part L compliance mean?
It means proving your building uses energy wisely, meets strict carbon targets, and includes the right heating, lighting, and insulation systems.
Who is responsible for meeting Part L?
The main contractor is responsible, but the entire team, designer, project manager, and energy assessor, shares the duty.
How do I prove that my site is compliant with Part L?
Submit a full set of labelled photographs from build stages and a completed BREL compliance report to building control.
Do I need to upgrade old homes to these standards?
If you carry out major works such as large extensions or loft conversions, yes. These areas now need to meet or closely match new build requirements.
Get Ready for the Future of Construction
We’ve helped clients all across the UK stay ahead of changing building regulations. At Ratio Seven, we’re here to make sure your build meets every energy rule without wasting time or money.
If you need help with airtightness testing, SAP assessments, or preparing your documentation, reach out to learn more.
Rules are changing quickly. Don’t let compliance hold you back. Get started now and let us help you build smarter, faster, and to the latest standards.
Explore more about Part L compliance and how it connects with your next project.
