Lighting is one of the most visible parts of a building and, in many offices, shops and public buildings, one of the largest uses of electricity. Upgrading old fluorescent, halogen and discharge lighting to LED, with modern controls, can cut energy use, reduce maintenance and improve the working environment. Done badly, it can create glare, flicker, nuisance tripping and gaps in emergency lighting.
This guide is for facilities managers, landlords and business owners considering an LED lighting upgrade. It covers why now is a good time to act, the options available, the regulations and standards that apply, and how to deliver the project with minimal disruption.
Key takeaways
- Fluorescent lamps are being phased out of the GB market, so replacement tubes will become harder to source. Plan your upgrade rather than waiting for failures.
- Replacing luminaires usually performs better than fitting LED tubes into old fittings.
- Design for people: light levels, glare, uniformity and colour all matter, not just watts.
- Controls such as presence detection and daylight dimming often deliver savings on top of the LED change itself.
- Do not lose emergency lighting coverage during the upgrade. Retest and update records afterwards.
Why upgrade now?
Fluorescent lamps are being phased out
In 2021 the government announced that sales of traditional fluorescent tube lighting, common in offices, would end from September 2023, alongside the end of most halogen bulbs, in its press release End of halogen light bulbs spells brighter and cleaner future. Since 1 September 2023, the common T8 tubes have not been allowed to be placed on the GB market, and further restrictions on other fluorescent lamps followed. Existing lamps can still be used, but as stocks are sold, replacement lamps become harder to find and more expensive. Buildings that wait for failures will end up replacing fittings piecemeal, at short notice and with mismatched results.
Energy costs and reporting
Large undertakings that qualify for the Energy Savings Opportunity Scheme (ESOS) must carry out energy audits and report compliance. Phase 4 has a qualification date of 31 December 2026 and a notification deadline of 5 December 2027, and participants must now report progress against action plan commitments. Lighting is often one of the most straightforward measures to identify and implement, which makes it a common feature of ESOS action plans.
Maintenance and building performance
Good-quality LED luminaires have long rated lives, reducing the frequency of lamp changes, which is especially valuable where access needs scaffolding, towers or out-of-hours working. Better lighting can also improve a building’s Energy Performance Certificate rating, which matters to landlords given the minimum energy efficiency standards for let commercial property.
Your options: retrofit lamps, new luminaires or a full redesign
There is no single right answer. The best option depends on the condition of the existing installation, the ceiling type, budget, and how long you expect to occupy the building.
| Option | Advantages | Disadvantages |
|---|---|---|
| LED replacement lamps or tubes in existing fittings | Lowest upfront cost; quick to install | Limited efficiency gains; old diffusers and reflectors reduce performance; some tubes require rewiring that alters the luminaire and can affect its certification and warranty; no controls |
| Like-for-like replacement LED luminaires | Good efficiency; reliable; new warranty; can add controls; minimal disruption to ceilings | Higher cost than tubes; may simply replicate a poor original layout |
| Full lighting redesign with controls | Best light quality and energy performance; layout matched to current use; integrated emergency lighting | Highest cost; needs design time; may involve more disruption and ceiling work |
Warning: Modifying an existing luminaire to accept LED tubes, for example by removing or bypassing the ballast, means the person doing the modification takes responsibility for the safety of the altered product. If you choose this route, use products and methods approved by the tube manufacturer and label the modified fittings clearly so nobody refits a fluorescent tube later.
Designing lighting for people, not just for watts
A lighting upgrade is a chance to fix problems that occupants have complained about for years: glare on screens, dark corners, harsh or flickering light. The Workplace (Health, Safety and Welfare) Regulations 1992, regulation 8, requires every workplace to have suitable and sufficient lighting, and natural light wherever reasonably practicable. The HSE’s guidance Lighting at work (HSG38) explains how to assess this.
For more detailed design criteria, lighting designers use BS EN 12464-1, the European standard for indoor workplace lighting, and the Society of Light and Lighting’s Code for Lighting and application guides. A good design considers:
- Illuminance: the right amount of light on the task, which differs between an open-plan office, a corridor, a store room and a retail display.
- Uniformity: avoiding patchy light and dark areas.
- Glare: limiting discomfort glare, particularly where people use screens.
- Colour rendering and colour temperature: how natural colours look, and whether the light feels warm or cool.
- Flicker: good-quality drivers minimise flicker, which can cause discomfort and headaches.
- Vertical surfaces: lighting walls and faces, not just desks, makes spaces feel brighter and more comfortable.
Over-lighting is common in older buildings. Measuring existing light levels during the survey often shows that fewer, well-placed luminaires can deliver better results.
Controls: where the extra savings come from
LED luminaires use less power, but lights left on in empty rooms still waste energy. Controls tackle when and how much light is used:
- Presence and absence detection: lights switch on when people enter, or must be switched on manually and then switch off automatically when the space is empty. Absence detection is often better in offices and meeting rooms.
- Daylight dimming: sensors reduce artificial light near windows when daylight is sufficient.
- Time scheduling: switching off circulation and external lighting outside occupied hours, with safe overrides.
- Task tuning: setting maximum output below 100% where the design delivers more light than needed.
- Addressable systems: protocols such as DALI-2 allow individual luminaires to be monitored, grouped and reprogrammed as layouts change, and can report emergency lighting test results.
Controls must be commissioned properly. Detectors in the wrong place, time-outs set too short, or sensors that switch lights off on people working quietly at their desks soon lead to occupants overriding or disabling the system. Allow time for fine-tuning after occupation.
Some newer installations use Power over Ethernet (PoE) to power and control LED luminaires through data cabling. BS 7671 Amendment 4:2026 introduced a new section on PoE, which is worth discussing with your designer if you are considering this approach.
Building Regulations and Part L
In England, Approved Document L sets energy efficiency standards for fixed lighting in buildings other than dwellings. The current edition, the 2021 edition incorporating 2023 amendments, includes:
- A minimum average efficacy for general lighting of 95 luminaire lumens per circuit-watt
- A minimum for display lighting of 80 light source lumens per circuit-watt, or an alternative power-density or calculation route
- Automatic controls in spaces that are likely to be unoccupied, and daylight controls where spaces receive significant daylight
- Separate circuits for display lighting so that it can be switched independently of general lighting
A 2026 edition of Approved Document L was published in March 2026 alongside the Future Buildings Standard. It raises the general lighting efficacy figure and comes into force for most work from 24 March 2027, subject to transitional arrangements. If your project will run into 2027, check with your designer and building control body which edition applies. Choosing efficient luminaires now is a sensible way to stay ahead of the standards.
Electrical considerations
A lighting upgrade is electrical work, and it should be designed and certified under BS 7671. Several technical issues come up regularly:
Inrush current
LED drivers draw a short, high inrush current when switched on. Too many luminaires on one circuit can trip circuit breakers when the lights are switched on together. Manufacturers publish the maximum number of drivers per circuit breaker type and rating, and the design should respect it.
Earth leakage
Electronic drivers can have small protective conductor currents. Many luminaires on one RCD-protected circuit can add up and cause nuisance tripping. Circuit arrangement and RCD selection should allow for this.
The condition of the existing installation
Lighting upgrades often reuse existing circuits and wiring. Before committing, check the condition of the installation with a current EICR. Old rubber or heat-damaged cables above fluorescent fittings are not unusual in older buildings, and they are better found at the planning stage than halfway through the project.
Ceiling voids and asbestos
Work in ceiling voids in buildings built before 2000 must take account of the asbestos register and management survey. If the register does not cover the areas affected, further survey work may be needed before installation starts.
Waste
Fluorescent tubes contain mercury and must be disposed of as hazardous waste through an appropriate route, with waste transfer documentation retained. Old luminaires and control gear are electrical waste and should be recycled appropriately.
Keeping emergency lighting compliant
In many buildings, emergency lighting is built into general lighting fittings, with a battery and emergency module inside selected luminaires. Replacing those fittings means you are changing your emergency lighting system, and it must still comply with BS 5266-1, which was revised in 2025.
- Identify every emergency luminaire before work starts, using the emergency lighting drawings and logbook
- Confirm that the new design provides the required coverage on escape routes, open areas and high-risk task areas
- Make sure exit signs and emergency luminaires are not removed or obstructed during phased works
- Consider self-test or addressable emergency lighting to reduce manual testing in future
- Carry out a full-duration test once the new batteries have been charged in line with the manufacturer’s instructions
- Update drawings, the logbook and the fire risk assessment information
Our guide to emergency lighting testing under BS 5266 explains the ongoing testing duties.
Building the business case and delivering the project
A credible business case starts with a survey, not a catalogue. Record the existing luminaires, their circuit wattage, the hours they are on and the condition of the installation. Then compare like for like:
- Existing circuit watts multiplied by annual operating hours gives current lighting energy use
- Proposed circuit watts, adjusted for the effect of controls on operating hours and output, gives future energy use
- Multiply the difference by your electricity tariff for the energy saving
- Add savings from reduced lamp replacement and maintenance access
Avoid relying on generic percentage claims. The result depends heavily on what you are replacing and how the building is used. Tax treatment of lighting expenditure varies, so speak to your accountant about any capital allowances that may apply.
Delivery should minimise disruption: phased work by floor or zone, out-of-hours working in occupied areas, sample installations so stakeholders can approve light quality before full roll-out, and a clear handover with certificates, as-fitted drawings, controls settings and user guidance. Building the new lighting into your planned maintenance programme keeps it performing as designed.
How JKS London can help
JKS London is an NICEIC-approved electrical and M&E contractor, established in 2004, delivering installations and refurbishments from minor works to turnkey projects for commercial, public sector, airport and retirement living clients across London and the South East. We can survey your existing lighting and electrical installation, plan and install LED luminaires and controls, integrate and test emergency lighting, and provide the certification and records you need.
Find out more about our installations and refurbishment services and electrical compliance work, book emergency lighting test and certification online, or contact us for a free, no-obligation site visit.
Frequently asked questions
Can I just put LED tubes into my existing fluorescent fittings?
Sometimes, but it needs care. Some LED tubes require the luminaire to be rewired to bypass the ballast, which changes the product and can affect its certification and warranty. Replacing the luminaire is usually the more reliable option and often gives better light quality and efficiency.
Are fluorescent tubes banned in the UK?
Existing fluorescent lamps can still be used, but the most common T8 tubes could no longer be placed on the GB market from September 2023 under ecodesign rules, and further restrictions on fluorescent lamps followed. As stock runs out, replacement tubes are becoming harder to source.
Do LED upgrades need Building Regulations approval?
Approved Document L sets efficacy and control standards for new and replacement fixed lighting in buildings other than dwellings, and some lighting work is notifiable. Your contractor or building control body can confirm what applies to your project, and the electrical work must be certified under BS 7671.
Will an LED upgrade affect our emergency lighting?
It can. Emergency luminaires are often combined with general lighting fittings, so replacing them changes your emergency lighting system. The upgraded system must still meet BS 5266-1, and it should be tested and the records updated once the work is complete.
How do we work out the savings from an LED upgrade?
Compare the circuit wattage of the existing and proposed lighting, multiplied by realistic operating hours and your electricity tariff, then add the effect of controls and reduced maintenance. A survey of the existing installation gives far more reliable figures than generic estimates.
Written by the JKS London technical team. NICEIC-approved engineers and compliance specialists maintaining airports, retirement villages, commercial and public-sector buildings since 2004. This guide is general information — for advice on your premises book a free site visit.
