LED lighting in a commercial building
Lighting is usually the shortest payback on the list. In a warehouse still running old high bay fittings it is the first thing to do.
What it actually is
Old fittings are replaced with LED units and controls, so lights dim or switch off where nobody is working.
Each fitting draws less. Controls stop the ones that need not be on.
An LED retrofit replaces existing fittings with LED units and, in most good schemes, adds controls so that light is only produced where and when somebody needs it. The fabric, the layout and the way you use the building all stay as they are.
There are two savings, not one. The first comes from the fitting itself drawing less power for the same light. The second comes from the controls turning lights off, or dimming them, in areas nobody is using and in areas already lit by daylight. On many sites the second is larger than the first, and it is the one most often left out of the quote.
Lighting is usually the shortest payback on the list, and it is the measure with the fewest conditions attached. There is no grid application, no roof survey, no planning question and no risk of stranding an asset. In a warehouse still running old high bay discharge fittings it is nearly always the first thing to do.
There is a second benefit that does not show on a bill. Old discharge lighting is dim, slow to strike and uneven. Modern lighting is instant, better distributed and easier to work under, and in a warehouse or a production area that is a genuine operational gain rather than a marketing line.
Which buildings it suits, and which it does not
It suits buildings still on discharge or fluorescent fittings, and buildings lit for long hours. Warehouses, production areas and multi shift sites.
It suits you less if the building was relamped recently, or if lit hours are short.
- Warehouses with high bay discharge fittingsGood fitThe strongest case there is. High wattage fittings, long hours, and controls that can switch aisle by aisle.
- Manufacturing and multi shift sitesGood fitLong lit hours multiply every watt saved. Zoning by production area adds more.
- Cold storageGood fitLess waste heat from lighting means less work for the refrigeration plant as well as a lower lighting bill.
- Car parks, external areas and stairwellsGood fitOften lit continuously, rarely occupied. Presence detection is where most of the saving sits.
- Offices on older fluorescent fittingsGood fitDaylight dimming near windows and presence detection in meeting rooms and circulation add a lot to a straight swap.
- RetailDependsDisplay lighting is a merchandising decision as much as an energy one. Colour rendering and appearance matter more here than anywhere else.
- SchoolsDependsGood hours in term time but long holidays. Controls and lighting quality in teaching spaces matter as much as the wattage.
- Recently relamped buildingsRarelyIf the fittings are already LED, the remaining gain is in controls, not in hardware.
- Buildings lit for very short hoursRarelyFew hours means little saving, whatever the fitting.
What it typically costs and saves
- Installed cost
- from £7 to £20 per square metre
- Reduction in lighting energy
- 40 to 70 per cent
- Lighting share of site energy
- 15 to 30 per cent
- Observed payback
- 1.5 to 3.5 years
What drives the variation
- •Mounting height and the access equipment it requires.
- •Whether the work is done in normal hours or out of hours around your operations.
- •How much control gear is included, and whether it is wired or wireless.
- •Whether existing wiring and emergency lighting can be reused or needs replacing.
- •Fitting quality, warranty length and colour rendering.
- •Any asbestos or age related complication in older ceilings.
How this appears on your building
What decides whether it works on your building
What is fitted now
Old discharge and fluorescent fittings give the largest gain. If the building has already been relamped with LED, the honest answer may be that only the controls are worth doing.
Hours of operation
Savings are a straight function of hours. A three shift site gains far more from the same work than a single shift one, and that is what shortens the payback.
Lit area and mounting height
High spaces need higher output fittings and access equipment. Both raise the cost per square metre, though they usually raise the saving too.
Whether controls can be added
Presence detection, daylight dimming and zoning are where the difference sits between an adequate scheme and a good one. Ask what proportion of the saving comes from controls.
Access
Working at height over live racking, machinery or a trading floor is slower and more expensive than working in an empty unit, and it may push the work into nights or weekends.
Required light levels
Different tasks need different levels, and there are standards for workplaces. A scheme that saves money by simply lighting the space less is not a saving, it is a downgrade.
How long it takes and what it disrupts
Survey and design
A fitting by fitting count, a lighting calculation for the required levels, and a controls strategy. Short, and it is what separates a designed scheme from a swap.
Installation
Usually done area by area so the building keeps working. This is the least disruptive measure on the list, and in many buildings staff simply notice better light one morning.
Out of hours working
In retail, production and busy warehousing the work often happens at night or at weekends. That costs more per fitting and disrupts less. Ask for both prices.
Commissioning the controls
Sensors and dimming need setting up against how the space is really used, and reviewing a few weeks later. If nobody does this, the controls end up disabled and the saving disappears.
What usually goes wrong or gets missed
Fittings swapped one for one with no controls
The simplest quote to produce and the one that leaves the most money behind. Ask what a controls option would add and what it would save.
Light levels cut too far
A cheaper scheme that leaves a space dim or uneven is a false saving, and in a workplace it can be a safety matter.
Access billed separately
A supply only price looks excellent until the scaffold tower and the out of hours labour arrive as extras. Check what the price includes.
Emergency lighting forgotten
It has its own requirements and its own testing regime, and it is frequently discovered mid project.
Controls commissioned and never reviewed
Sensors set too sensitive get overridden by staff, then disabled. A review visit after a few weeks protects the saving.
Warranty terms not read
Long warranties often depend on operating hours and temperatures. In a cold store or a hot production area that matters.
- •Fittings are swapped one for one without controls, so half the saving is left behind.
- •Lux levels are cut too far and the space becomes unpleasant or unsafe to work in.
- •The quote covers supply only and access at height is billed separately.
What to ask an installer
- 01What is fitted now, how many of each, and how many hours does each area run?
- 02What share of the saving comes from the fittings and what share from the controls?
- 03What light levels does the design achieve, and against which standard?
- 04Does the price include access, working at height and any out of hours labour?
- 05What is the price with the work done in normal hours and out of hours?
- 06Does this cover emergency lighting, and does it include the testing regime?
- 07Can the existing wiring be reused, or is rewiring included?
- 08What warranty applies, and does it depend on hours or temperature?
- 09Who commissions the controls, and will you return to review the settings?
- 10What happens to the old fittings, and is disposal included?
How it interacts with other measures
With solar
Do lighting first. A lower electrical load means a smaller array is needed to cover the same share of your consumption, so you spend less on both.
With a heat pump or heating work
Old lighting throws off heat. Removing it slightly increases the heating demand in winter and reduces the cooling demand in summer. In a cooled or refrigerated space the net effect is clearly positive.
With voltage optimisation
Old discharge lighting responds to reduced voltage. LED lighting largely does not. Doing lighting first can remove much of the case for voltage optimisation, so assess lighting before committing to it.
With an EPC rating
Lighting is a direct modelled input to a non domestic assessment, and it is usually the cheapest single way to move a band.
Does it move an EPC rating
Lighting is a modelled input to a non domestic EPC, so a retrofit can move a rating.
Ratings matter most if you let the building. Our guide to MEES and the commercial EPC standard sets out the thresholds, the dates and what to do if a building falls short.
Common questions
How much does an LED retrofit save?
In commercial buildings a retrofit against legacy discharge and fluorescent fittings typically removes 40 to 70 per cent of lighting energy, and lighting is commonly 15 to 30 per cent of site energy. The position within those ranges depends on what is fitted now, how many hours it runs, and whether controls are included.
How quickly does LED lighting pay back?
Observed commercial paybacks run from about one and a half to three and a half years. Long operating hours and old high wattage fittings put you at the short end.
Is it worth adding controls?
Usually yes, and in car parks, stairwells, storage aisles and meeting rooms the controls can save more than the fittings do. Ask for the saving to be broken down between the two.
Will it disrupt my operations?
Less than any other measure here. Work is normally done area by area, and where that is not practical it is done at night or at weekends for a higher labour cost.
Will LED lighting improve my EPC rating?
It can, because lighting is modelled directly in a non domestic assessment. It is generally the cheapest route to a band improvement.
Can I just change the lamps rather than the fittings?
Sometimes, but retrofit lamps in old fittings keep the old optics and the old control gear, so you gain less and you cannot usually add proper controls. Have both options priced.
Related reading
Where these figures come from
Show the provenance
- Installed cost: from £7 to £20 per square metre
- Derived from a published commercial retrofit worked example.
- Reduction in lighting energy: 40 to 70 per cent
- Commercial LED retrofit against legacy discharge and fluorescent fittings, 2026 market data.
- Lighting share of site energy: 15 to 30 per cent
- Commercial building energy use, 2026.
- Observed payback: 1.5 to 3.5 years
- Commercial LED retrofit market data, 2026.
The figures on this page are modelled ranges for UK commercial buildings, not a quote for yours. Add your building and we will model it on your own roof, load and rating.