Lighting legislation and energy use A guide to England’s Building Regulations

Lighting legislation and energy use

A guide to England’s Building Regulations

Energy conservation is a legal responsibility set out in the Building Regulations 2010 and it is important that your lighting design meets the legal requirements.

This guide will help you to understand your responsibilities when planning a lighting project.

Building Regulations 2010

The Building Regulations 2010 relate to almost all new domestic, commercial and industrial buildings in England. They also cover some existing buildings, for example those which are undergoing refurbishment.

Updates to the Building Regulations were published in 2021 and additional documents were also published to provide guidance relating specifically to reducing energy use –  Approved Document L: Conservation of Fuel and Power (parts L 2021).

• Volume 1 relates to dwellings
• Volume 2 relates to buildings other than dwellings

These documents were subsequently revised by the Department for Levelling Up Housing & Communities (DLUHC) and came into force in England June 2022.

What does the guidance mean for me?

Both documents relate to the energy efficiency and controls of fixed building services, i.e. those which are part of the fabric of the building. This includes lighting systems.

The documents state that lighting must be…

• Energy efficient to a reasonable standard
• Have effective controls and
• Are commissioned by testing and adjustment

…to ensure they use no more fuel and power than is reasonable in the circumstances.

Volume 1 (Dwellings)

Fixed light fittings should be selected so they:

• Provide lighting levels appropriate to the activity in the space
• Do not over-illuminate the space

Note: Luminous efficacy is a measure that tells you how well a light source produces visible light. It is measured in light source lumens per circuit-watt (Lm/W)

Internal light fittings

• Each light fitting installed into a new or existing dwelling should have lamps with a minimum luminous efficacy of 75 Lm/W.

• They should have local controls to enable the separate control of lighting in each space or zone. The controls can be manual, automatic or a combination of both.

External light fittings

• Each external light fitting installed in a new or existing dwelling should have automatic controls which switch luminaires off in response to daylight.

• If luminous efficacy is 75 Lm/W or less, they should also have automatic controls which switch luminaires off after the area being lit becomes unoccupied.

• If luminous efficacy is greater than 75 Lm/W, manual control is acceptable.

Lighting control systems

• A building automation and control system should have control capabilities which are appropriate for the type of building, its expected use and potential energy savings.

• The system should be specified and installed according to the manufacturer’s instructions, to ensure its overall performance meets a reasonable standard.

Volume 2 (Buildings other than dwellings)

This relates to large or more complex buildings. The approved document does not include minimum standards for specialist lighting such as theatrical spotlights, stage lighting, gobo projectors or wall-washers.

Fixed light fittings should be selected so they:

• Achieve levels of illumination appropriate to the activity in the space
• Do not over-illuminate the space

Design for larger spaces should be based on CIBSE’s SLL Lighting Handbook or an equivalent design guide.

There is no expectation to produce lighting calculations for smaller spaces such as toilets or storerooms, where total lighting power is likely to be low.

General lighting

• Should have an average luminaire efficacy of 95 Lm/W, or
• Meet the requirements of the Lighting Energy Numeric Indicator (LENI) method

Display lighting

• Should have an average light source efficacy of 80 Lm/W, or
• Have a rated power usage no greater than 0.3W/m2 within each space, or
• Meet the LENI method

For high excitation purity light sources (those which produce colours that are vivid and true to life) an average light source efficacy of 65 lumens per watt.

Light metering

Both general lighting and display lighting should be metered by one of the following:

• On dedicated lighting circuits with a kWh meter for each circuit, or
• By a local power meter coupled to or integrated in the lighting controllers of a lighting management system, or
• By a lighting management system that can calculate the energy consumed and make this information available to a building management system.

Lighting controls

Lighting used in new and existing buildings should follow the guidance contained in BRE Digest 498:

• Unoccupied spaces should have automatic controls to turn the general lighting off when the space is not in use
• Occupied spaces should have automatic controls suitable for the use of the space

General lighting in occupied spaces should have daylight controls, such as photo-switching and dimming for areas likely to receive high levels of natural light.

Display lighting should be controlled on dedicated circuits that can be switched separately from those providing general illuminance.

Consequential Improvements

Appendix D in the guidance relates to measures for ‘consequential improvements’ in an existing building with a total useful floor area of over 1000m2.

Consequential improvements are any additional work which may be required to improve the overall energy efficiency of the building, if the proposed work consists of or includes:

• An extension
• Provision of a new fixed building service (including lighting)
• Increasing the capacity of any fixed building service (including lighting)

To meet the guidance criteria, lighting systems that have an average lamp efficacy of less than 60 Lm/W and that serve areas greater than 100m2 by should be upgraded to:

• Provide new light fittings and/or controls, following the guidance detailed in the sections above
• Install energy metering in line with the guidance in CIBSE TM39

We all want to do our bit to protect the environment. By following the guidance above, you can be confident that your lighting project is sustainable, efficient and cost-effective.

You can access the full guidance documents here