Part L Building Regulations

With changes to Part L, the spotlight is on energy-efficient solutions like thermostat/temperature controllers.

Part L Building Regulations

With updates to Part L of the UK's Building Regulations being rolled out nationwide, all buildings constructed from June 2022 onwards – be they residential or commercial – must now meet new energy efficiency requirements.

What you need to know

How will the changes affect you?

The updates cover 4 groups: Part L1A ensures all new houses built from June 2022 onwards are both energy efficient and in compliance with all current Building Regulation requirements. Part L1B concerns all renovations and extensions carried out on existing homes, the likes of which must also meet certain energy efficiency standards.

The last 2 sections, Part L2A and Part L2B, focus on any building that is not a dwelling.

Essentially, for heating installers*, the updates mean reasonable provisions must now be made for the conversion of fuel and power in buildings via fixed services such as:

Installation of effective controls – i.e., Electronic Room Controls and Thermostatic Radiator Valves (TRVs and ERCs).

Testing and adjusting of every thermostat controller (also referred to as temperature controllers) to ensure systems only use as much fuel and power as needed – with our dynamic RAS-B2 TRV designed to optimize system balancing so you can guarantee boiler efficiency while improving user comfort and your working life. *Please note, changes are being rolled out across England, Wales and Scotland in three phases. For more information, follow the links provided.

Part L – key takeaways

Now, when a boiler is replaced in an existing dwelling …

  • Each room will be fitted with a thermostat controller to manage heat output. For a system with radiators, this means adding TRVs to every radiator except those in whichever room houses the central thermostat.
  • System or open vent boilers will now require an independent time control (e.g. programmer) for their heating and hot water circuits as well as a boiler interlock (e.g. room thermostat and cylinder thermostat with motorised valves).
  • Combi boilers now require 1 of 4 ‘Boiler Plus’ functions/additions: flue gas heat recovery, load compensation, weather compensation or a smart thermostat.
  • System controls should be wired so that heating appliances and pumps switch off when there is no demand for space heating or hot water.

Where should I begin?

Find the right device for your needs.

To ensure we adapt to Part L as smoothly as possible, Danfoss has been working with the people who know best – that's you – to create the solutions you need to get the job done.

Like our new and improved ERCs designed from beginning to end with the help of heating installers. With easy-to-fit features including new industry-standard backplates, multiple access cable designs and clear, intuitive displays, these highly reliable solutions have been engineered with you and your customers in mind.

New and improved Electronic Room Controls
Don't miss out – visit us and discover everything you need to know about thermostat/temperature controllers.

Installer Life on Tour 2023

Coming to a town near you

Come and meet our newest family members. Learn how Danfoss can help you comply with Part L by catching our Danfoss Installer Life Tour. We'll be visiting wholesalers across the country so all you need to do is hitch a ride when we pass through your area and we'll do the rest.

Once onboard, our team of experts will be on hand to provide short product demonstrations and explain how we’re making installers’ lives easier with solutions like our new and improved and fully compliant ERCs.

To find out more, simply get in touch with us below:


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Check out the range below:

(Please note, all solutions can be programmed to show readings in Celsius or Fahrenheit)

The Danfoss RAS-B2 comes with a unique differential pressure controller, thus ensuring all radiators in a building receive the right amount of heat all year round.

A new era of thermostat controller

Our latest heating solutions also include the RAS-B2, our CEN-approved, self-balancing TRV. Used in coordination with the Danfoss Installer App, the RAS-B2 can help you optimise your customers’ heating systems to ensure boilers remain in condensing mode for longer, thereby saving them money whilst ensuring every room heats up evenly.

Everything you need in one place

We also recommend checking out our Danfoss Installer App. Loaded with installation guides, digital tools, and product information, use the app to make quick calculations when it comes to radiator pre-setting, hydronic balancing, and much more

What's more, the app’s handy shopping basket tool allows you collect all the products you need in one place before sending an order to your wholesaler via text message, e-mail or WhatsApp.

Why not download Danfoss Installer App today and start making your Installer Life easier?

Download the App
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Building Regulations Part L covers the conservation of fuel and power in the building of new homes and establishes how energy-efficient new and existing homes should be. This means that there are certain requirements when installing or re-fitting controls with the aim being to increase energy efficiency in property. It is worth noting that different rules apply in different areas of the UK, so please check the regulations in your region.

In contrast to other TRVs which only act as flow limiters, the innovative design of the Danfoss RAS-B2 features a differential pressure controller that ensures all radiators throughout the home get the heat they need throughout the year regardless of whether it is spring, autumn or winter. Additionally, pre-setting of the desired flow is done on the valve rather than on the lockshield. Something which, it is estimated, could save installers up to two hours of valuable working time.

The new range of Danfoss Electronic Room Controls have been 100% co-created with installers. These new ERCs are quicker and easier to install, have a new industry standard backplate , multiple cable access design and a full white exterior. With an intuitive display and simple controls, the new range of ERCs from Danfoss are easy to install and easy to use. Finally, we are so confident in the reliability of our new range, we have increase the warranty from 2 to 5 years.