Updated 24th March 2026
CURRENT BUILDING REGULATIONS
Statutory guidance Approved Document L (2026)
Do the products you use comply?
All UK buildings must comply with the regulations produced by the UK government; specifications must ensure that the lighting designs utilise conforming products. and that those products are installed by the electrical contractors. The resposibility lies with the landlord, building occupier or owner of the premises.
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Building Regulations Document L Volume 1 Dwellings.
General Principles
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Efficacy Accounting: Calculations for both the dwelling primary energy rate and the dwelling emission rate must take into account the efficacy of light sources installed in fixed lighting locations.
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Illumination Levels: Fixed lighting must achieve lighting levels appropriate to the activity in the space without over-illuminating.
Here is the summary of the specific lighting requirements outlined in Approved Document L, Volume 1 (2026 Edition):
Internal Lighting Requirements
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Minimum Luminous Efficacy:
Each internal luminaire installed in a new or existing dwelling must feature light sources that achieve a minimum luminous efficacy of 105 (LP/W) light-source lumens per circuit-watt.
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Specialist Light Sources:
Non-standard specialist light sources have specific lower minimum efficacy requirements:-
High excitation purity light sources: Minimum 65 lumens/circuit-watt}.
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Tunable LED devices: Minimum 80 (umens/circuit-watt}.
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Light sources with a Colour Rendering Index (CRI) 95 (rA): Minimum 80 (Lumens/circuit-watt}.
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Local Controls: Internal luminaires must have local controls (manual, automatic, or a combination) allowing separate control of lighting in each space or zone.
Fixed External Lighting Requirements
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Minimum Luminous Efficacy: External luminaires installed in new or existing dwellings must meet the standard 105 (LP/CW) light-source lumens-per-circuit-watt efficacy threshold or the specialist light-source limits detailed above.
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Control Requirements: External lighting must be provided with both:
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Daylight sensors: Automatic controls that switch off the luminaire in response to daylight.
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Occupancy controls: Controls that switch off the luminaire after the area becomes unoccupied:
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Total flux 1200 lumens: Must use automatic proximity sensors.
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Total flux 1200 lumens: Manual controls are acceptable.
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The step up in Part L requirements from previous standards (which sat at 75 (LM/PW) to the 105 (LM/PW) minimum standard reshapes how common UK residential lighting products are specified.
While commercial fittings have achieved 120-150+ (LM/PW) for years, domestic luminaires, particularly compact fire-rated downlights and decorative architectural fittings, face distinct technical challenges under this rule.
GU10 Mains-Voltage Lamps: Non-Compliance
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Standard retrofit GU10 LED lamps (the baseline for UK housebuilders and refits) typically deliver between 70 (LM/PW) and 90 (LM/PW).
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All GU10 LEDs from major high-street brands fall short of 105 (LM/PW). High thermal stress inside a small GU10 enclosure makes driving LEDs harder while maintaining high efficacy.
Integrated LED Fire-Rated Downlights: Mixed Compliance
Integrated downlights are heavily affected by driver efficiency, optical diffusers, thermal management, and colour-tuning features.
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Standard Single-CCT / Dual-Wattage Downlights (Compliant):
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Modern architectural integrated downlights (e.g., Light Projects, Phos & Lucent) pushing high-efficiency LED chips easily reach 105 (LM/CW) on standard CCT settings (e.g., 4000K/3000K). Lumen outputs are lower the warmer the colour.
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Smart & RGB+TW / Tunable White Downlights (Non-Compliant or Conditionally Compliant):
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Smart integrated downlights using RGB + Tunable White technology (e.g., Light Projects, Tryka, Smart Lighting Systems) typically yield only 65 (LM/CW) due to mixed-chip optical losses.
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Compliance Catch: Unless these smart fittings qualify as Tuneable LED devices (which carry a lower limit of 80 (LM/CW), standard smart downlights fail.
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High-CRI 95 (rA) & Architectural Specialist Fittings: Compliant via Exceptions
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Market Status: Premium architectural luminaires (used in luxury domestic settings) often prioritise Colour Rendering Index {CRI} 95 (rA) or warm-dim features over raw lumen output. High CRI phosphor coatings reduce raw lumen efficiency.
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How They Fare: These fittings typically deliver between 80 (LM/PW) and 95 (LM/PW). Under standard criteria, they would fail. However, because the document explicitly lowers the threshold for {CRI} 95 (rA) light sources to 80 (LM/PW), premium architectural fittings pass.
LED Panels, Linear Strips & Batten Fittings: Fully Compliant
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Market Status: Surface battens, continuous linear runs, and LED plaster-in profiles routinely hit 110 - 140 (LM/CW) (e.g., Light Projects, Phi Lighting, Eureka Lighting).
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How They Fare: These fit comfortable above the 105 (LM/CW) baseline. The primary focus for these products is controls: ensuring linear setups in utility rooms, garages, or kitchens feature proper local or automatic control zone switching.
Outdoor Wall Lights & PIR Luminaires: Requires Hardware Audits
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Market Status: External decorative fittings (up/down wall lights, porch lanterns) have historically used lower-efficiency LED modules around 70 - 85 (LM/CW).
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How They Fare:
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Efficacy: Integrated outdoor fixtures must be checked for the 105 (LM/CW) minimum.
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Controls: The controls requirement catches many popular items. A basic manual switch on an outdoor light over 1200 (lm) will render it non-compliant; it must have an automatic PIR / proximity sensor. Manual override switches are only permitted on smaller fittings 1200 lm).
Summary Checklist for Product Specification
Product Catagory
Typical market efficacy (LM/PW)
Compliance with new target
Standard GU10 LED Bulbs
Standard integrated downlights
RGB/TW (colour-changing or tunable white) smart downlights
High CRI (>95 rA) Architectural
External Luminaires
Key Action
70 - 90 (LM/PW)
105 - 120 (LM/PW)
65 - 90 (LM/PW)
80 - 95 LM/PW)
Varies
NO (ALL FAIL)
YES
CONDITIONAL
YES
CONDITIONAL
Upgrade spec to conforming integrated downlights.
Verify manufacturer data sheets for net circuit watts.
Must meet the 80 (LM/PW) tunable exemption criteria.
Qualifies under the reduced 80 (LM/PW) CRI exemption.
Must achieve 105 (LM/PW) and feature automatic PIR sensors.
Do the products you use comply?
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How do I know if my products meet the new regs?
To ensure that your chosen or preferred products comply with the new 2026 Building Regulations, we have designed an interactive model:
Follow these instructions
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Enter the product wattage.
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Enter the total lumens output for the product as published in the manufacturer's data.
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Select the tick if the wattage is the published wattage only.
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Unselect the tick if the wattage includes circuit losses for driver/gear.
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Select from the Building Application Type, applicable to your type of project.
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Results are shown in the calculated Efficacy at the bottom.
You are currently viewing the information for Dwellings to see information for all Buidings other than dwellings
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The information above is intended to be used as a guide only, this does not mean that all criteria has been met and cannot be used for duplication or to accompany a planning application.