United Kingdom Building Regulations - Energy Efficiency
Stoane Lighting place this symbol on product pages where the light sources available in the luminaire makes the product suitable for use (internal or external) in a dwelling or in a display lighting application of a building other than a dwelling. By today's building regulations (in England, Wales and Scotland) the light source lumens per circuit watt in the majority of configurations exceeds the higher of the 2 thresholds; 80 light source lumens per circuit watt.
We recognise that luminaire efficacy, which is relevant to buildings other than dwellings for general lighting applications, is more complicated to convey simply because the efficacy threshold is for the Luminaire and not the light source (so one must consider the optical and electrical efficiency of the luminaire as a system of parts). Stoane Lighting will support projects /requirements by providing specific configuration data on request, for L marked products there will be configurations exceeding the threshold.
What is Part L?
This topic might often be distilled down to, or referred to, as ‘Part L ‘ requirements in lighting scheme building regulation compliance discussions. Part L is a reference to the English (and Welsh) building regulations Approved Documents L: Volumes 1 and 2.
These are building regulations that set requirements relating to energy efficiency in the built environment, including some for lighting.
Whilst England and Wales have documents called Part L: Volumes 1 and 2, Scotland covers the topic in its Technical Handbooks (section 6) and Building Services Compliance Guides, and Northern Ireland in Technical Booklets F1 and F2. Whether referred to a 'Part L' or not, we are really talking about building regulations. Here we are looking at the lighting specific requirements.
Regardless of the region, the building regulations cover Dwellings/Domestic property and Buildings other than Dwellings/Non-domestic with separate lighting requirements for each.
At the time of writing the regulations have some differences depending on region. Whilst there is alignment on lighting requirements between England, Scotland and Wales, Northern Ireland differs.
Are the lighting specific requirements aligned?
At the time of writing (July 2025), no. Whilst there is alignment on lighting requirements between England, Scotland and Wales, Northern Ireland differs.
When updates happen they don’t typically happen at the same time, so updates in English Building Regulations have in the past been followed by aligned updates to Scottish and Welsh regulations.
What are the main requirements for dwellings/domestic properties that relate to lighting equipment specifications? (18/08/2025)
In England, Wales and Scotland:
For general lighting, the average efficacy should
be >95 luminaire lumens per circuit-watt OR the LENI
methodology is used to demonstrate compliance.
For display lighting, the average efficacy should be >80 light source lumens per circuit-watt OR the LENI methodology is used to demonstrate compliance.
In Northern Ireland:
For general lighting, the average efficacy should
be >/=60 luminaire lumens per circuit-watt OR the LENI
methodology is used to demonstrate compliance.
For display lighting, the average efficacy should be >/= 22 light source lumens per circuit-watt OR the LENI methodology is used to demonstrate compliance.
What is LENI?
Lighting Energy Numeric Indicator (LENI) is a measure of the performance of lighting in terms of energy per square metre per year (kWh/m2 per year). This is methodical approach that considers daytime energy use, night time energy use, occupancy and lighting power to establish if the design falls under the limit prescribed for that situation in the regulations. Designers may opt for this approach over analysis of luminaire efficacy for general lighting or light source efficacy for display lighting.
Will the requirements change?
The government in England launched a draft update of Part L: Volumes 1 (dwellings) and 2 (other than dwellings) for consultation in December of 2023. Changes are forecast to be implemented in late 2025. However, there has not been confirmation if the changes will go ahead as proposed in the draft, or whether that will happen on the timeline previously indicated.
Note that these are changes proposed to English Building Regulations so if they change the requirements may for a time be different to those of Scotland, Wales and Northern Ireland.
Stoane Lighting will update this page when new building regulations are confirmed and published. Our products marked with an L, indicating they will meet thresholds, are marked as such with the new efficacy thresholds that are anticipated under new English Building Regulations.