By Alistair Brown, CEO of LumenStream
Last updated: 31 July 2026
Commercial lighting in a UK facility comes down to four things a facilities manager can control: the light level each space is designed to hit, the efficiency of the fittings delivering it, the quality of the survey behind any upgrade, and how the installation is phased around your operations. Swapping halogen for LED cuts lighting energy by 65 to 85% (Carbon Trust), and around 20% where you are replacing older fluorescent or high-intensity discharge fittings.
This article covers the standards, the data-sheet terms, what happens to a working site during an upgrade, and how to fund one without capital. It is written for the facilities manager, not the lighting engineer.
What lux levels does my facility actually need?
For general manufacturing areas and classrooms, the design level is 300 lux. That figure comes from BS EN 12464-1, the standard UK lighting designers work to for indoor workplaces. It is the anchor for most of the spaces a facilities manager runs.
The level moves with the task.
The more detail the work involves, the more light it needs. HSE's lighting guidance puts a corridor or walkway at around 50 lux, a process control room at 300 lux, and close work such as studying an engineering drawing at 750 lux.
| Area or task | Typical design level |
|---|---|
| Warehouse aisles (unmanned racking) | 50 to 100 lux |
| Corridors and walkways | Around 50 lux |
| Warehouse aisles (manned picking) | 150 to 200 lux |
| Loading bays | 150 to 200 lux |
| Rough assembly | 200 to 300 lux |
| General manufacturing areas, classrooms, process control rooms | 300 lux |
| Medium assembly, food production lines | 300 to 500 lux |
| Food preparation areas | Around 500 lux |
| Detailed drawing and inspection work | 750 lux |
| Fine inspection, engraving, precision work | 1,000 lux |
These are the design bands from BS EN 12464-1 and HSE guidance; every space should still be designed to the exact task value in the standard, which is what a proper survey establishes.
Most sites we survey are running below the levels their spaces were designed for.
Nobody notices, because eyes adjust to a gradual decline. A handheld lux meter tells you in seconds whether a space meets its design level. That is why the levels are checked by measurement rather than judged by eye.
Over-lighting is the quieter problem.
Every lux above the design level is energy you pay for with no gain in safety or output. Hitting the standard matters in both directions, and it is the first thing to check in any design you are offered.
What do the numbers on a lighting data sheet mean?
Five numbers on a technical data sheet tell you almost everything about a fitting: wattage, lumens, efficacy, colour temperature and colour rendering.
| Term | What it tells you | Why it matters to you |
|---|---|---|
| Rated wattage | The total energy the fitting draws | It is the number your electricity bill responds to |
| Lumens | The total amount of light the fitting produces | It is the light half of the efficacy figure below |
| Efficacy (lumens per watt) | How much light you get for every unit of energy | It is the number to compare fittings on: what efficiency means in lighting |
| Colour temperature | How the light looks, measured in kelvin | Lower values are warmer and more orange; higher values are cooler and bluer |
| Colour rendering index (CRI) | How true colours appear under the light, on a scale where 100 matches daylight | It matters most where detail matters, such as product inspection, quality control and retail |
Rated life is the sixth number, usually written as L70: the point where a fitting's output has faded to 70% of new, because LEDs dim gradually rather than failing outright. What that fade means for a system you already own is covered in We already have LEDs. What now?
How disruptive is an LED upgrade to a working site?
Less than most facilities managers expect: our installation teams fit around 500 luminaires a week, and the work is planned so your operations carry on around it.
Three things make that possible.
- The survey and design are finished before anything arrives on site, so there is no exploratory work happening during installation.
- The installation is phased, section by section, so no area loses its lighting all at once.
- Where a space cannot pause at all, the work moves to evenings, nights or weekends.
For example, at HPH Group, one of our UK customers, the job was harder than a straight swap. Previous contractors had left the existing wiring in poor condition, and it needed rectifying before the new lighting could go in. The upgrade still went in around a working haulage and warehousing operation. The result was 371 LED fittings saving 42 MWh and 28 tonnes of CO2 a year, with the facility's energy efficiency improved by 58.54%.
Aidan Cookson, Health & Safety/Facilities Manager at HPH Group, described the process this way:
"From start to finish, LumenStream handled everything: bringing the equipment, providing knowledgeable staff, and carrying out the work seamlessly. We simply stepped back and let them do their job, and the whole process was effortless."
If carbon reporting sits in your remit too, that same phased approach makes lighting one of the few emissions projects that does not interrupt production. We cover that side in Reducing Carbon Without Disruption.
What does a proper lighting survey and design involve?
A proper survey measures your building as it is, and a proper design proves the new system on paper before a single fitting is ordered.
The survey collects the facts: fitting counts, mounting heights, operating hours, current lux readings and how each space is used. The design then simulates the new scheme in software (we use DIALux, the industry standard) to show the light level every area will receive. You can check that against the standards above instead of taking a contractor's word for it.
A good design protects you from two expensive failures.
- Over-lighting. A scheme that beats the design level by half again looks impressive at handover and then wastes energy for the next decade.
- Glare. Designs are checked against UGR (unified glare rating) limits, because glare is a health and safety issue as well as a comfort one.
There is a compliance angle worth knowing about.
If your buildings are rented commercial property, the government's June 2026 interim response on Minimum Energy Efficiency Standards sets a target of EPC B by 2031 for buildings over 1,000 square metres in England and Wales, where cost-effective. The secondary legislation to enforce it is still to come, but the direction is set. Lighting is one of the cheapest ways to move an EPC band, and a certified design gives you the evidence for it.
For the full facilities-management reference, the Society of Light and Lighting publishes Lighting Guide LG20: lighting and facilities management through CIBSE.
One honest note: a survey can come back telling you not to upgrade.
If your fittings are recent, the lux readings meet the design levels and your operating hours are short, the savings will not justify the work yet. When that is the answer, we say so, and measuring again a year later costs almost nothing.
How do I fund an upgrade without capital?
Through Lighting as a Service: we survey, design, fund, install and maintain the system, and you pay one fixed monthly fee out of the energy savings, with nothing upfront. Whether the agreement sits on your balance sheet depends on how it is structured, so ask your accountant to check the contract. The full picture, including the funding routes side by side, is in What is Lighting as a Service?
