A lighting quote reads in thirty seconds: a number of luminaires, a unit price, a total. That total is the only part of the cost visible on the day of the decision. The rest is spread over ten or fifteen years, line by line, on the electricity bill, in maintenance hours and sometimes in a complete redo after the first complaints. Breaking down this full cost almost always changes the decision.
The price of a luminaire says almost nothing about the cost of light
Two industrial high bays can look alike on a product sheet and behave very differently over fifteen years. What separates them comes down to four parameters: efficacy in lumens per watt, the quality of the driver, lumen maintenance over time and thermal performance in the real ambient conditions of the building. Current professional ranges most often sit between 120 and 180 lm/W depending on the family, and that gap is paid for every hour of operation, not just once at purchase.
The second invisible parameter is the number of points. A project priced per unit encourages copying the existing layout. Yet the existing layout was sized for old sources, with beam angles, efficacies and maintenance factors that have nothing in common with today’s. This is precisely what a photometric study reveals: the number of luminaires really needed to reach the regulatory level, zone by zone.
The four items of the full cost
1. Purchase and installation
Equipment, labour for removal and installation, any rewiring, hire of access equipment, removal and disposal of the old luminaires. It is the only item that appears on a quote.
2. Consumption
It is simple to calculate: installed power multiplied by operating hours, multiplied by the site’s real price per kilowatt hour, standing charge included. One installed kilowatt running 4,000 hours a year consumes 4,000 kWh a year, every year, without exception. Operating times vary widely: around 2,000 hours in standard offices, up to 6,000 or 8,000 hours in logistics and continuous production.
3. Maintenance
On an LED installation, failure rarely comes from the diode: it comes from the driver, the connectors or a poorly assessed thermal environment. Added to this is lumen depreciation, which is not a failure but which takes a zone below the regulatory threshold without anyone noticing.
4. Unbudgeted costs
Production downtime during the works, rework after non-compliance, complaints from workstations, administrative hours spent deciding. They appear in no spreadsheet, and yet they are the heaviest in proportion.
Item | Visible on the quote | Main lever |
|---|---|---|
Equipment purchase | Yes | Efficacy in lm/W and warranty period |
Installation and access | Yes | Number of points to treat |
Consumption | No | Installed power and controls |
Maintenance | No | Driver quality, access height |
Rework after complaints | No | Compliance with NF EN 12464-1 from the study stage |
Over ten years, the purchase most often represents between a quarter and half of the full cost of a new installation, and its share falls as soon as operating hours lengthen. Compared with the status quo scenario, that is, what the site would have spent without changing anything, it becomes clearly a minority.
Oversizing: paying three times for the same excess
One luminaire too many costs three times. It is bought. It is installed, wired, connected, which ties up high access and electrician time. Then it is powered for fifteen years. Added to this is a fourth, quieter cost: it is one more maintenance point to visit, test and replace.
Oversizing is almost never a choice. It comes from copying the existing installation like for like, from calculations made from the catalogue rather than the room, or from a maintenance factor taken with an excessive safety margin. Serious modelling removes material: it is often the most profitable saving in a project, even before the change of technology. At great heights, where each point is expensive to install and maintain, the difference is spectacular; Rexylum high bay luminaires are chosen first on their photometry and mounting height, not on their nominal power.
Maintenance at height: the real price of a replacement
In a 9-metre hall, changing a luminaire is not an equipment operation, it is a logistics operation. It takes an aerial platform or a scaffold, an operator qualified for work at height, a cordoned-off area, often an electrical lockout, sometimes a line stoppage. The cost of access frequently exceeds the price of the product replaced, and it costs as much for one luminaire as for ten if you go up only once.
Two practical consequences. First, it is better to group interventions and think in campaigns rather than case by case. Second, the quality of the driver and the manufacturer’s warranty weigh far more on a site at height than on an office floor at 2.70 metres. A five-year warranty on a product installed at 12 metres does not have the same economic value as the same warranty on a suspended ceiling panel.
Over ten years, a site does not pay for luminaires. It pays for the energy they consume and for the access needed to change them.
Rework after complaints: the most expensive item of all
A technically working installation can be unusable. The reasons for complaints are always the same: direct glare at workstations, contrast too harsh between zones, colour temperature unsuited to the activity, perceptible flicker, insufficient uniformity creating shadow areas on the floor.
NF EN 12464-1 sets precise requirements for indoor workplaces: an illuminance to be maintained over the task area, a minimum uniformity, a limited unified glare rating and a minimum colour rendering index. For an office workstation, the usual reference is 500 lux with a UGR limited to 19. NF EN 1838 governs emergency lighting, NF X35-103 visual ergonomics, and the French Labour Code imposes the general obligation of result. An installation that does not meet them will have to be redone.
Redoing means paying again for access, paying again for installation, paying again for part of the equipment, and taking the zone out of use once more. It is the only item of the full cost that can, on its own, wipe out the energy saving of the whole operation. It is also the easiest to avoid: it is dealt with at the lighting audit stage, before purchase, with a lux meter and a calculation, not afterwards with incident tickets.
A costed case: an airport arrivals hall
The hall had 398 luminaires. The study brought the installation down to 315 points, that is 83 luminaires removed, while reaching the required levels. The consumption bill for lighting went from 12,197 euros a year to 3,340 euros a year.
Indicator | Before | After |
|---|---|---|
Number of luminaires | 398 | 315 |
Annual consumption | 12,197 euros | 3,340 euros |
Annual saving | 9,027 euros | |
Project budget | 27,405 euros | |
Payback time | 37 months | |
Net result at 5 years | 16,880 euros |
Read over ten years and at a constant electricity price, the same annual saving repeats: around 90,000 euros of avoided consumption for an initial budget of 27,405 euros. The purchase price then represents a fraction of what the site would have spent by doing nothing. And the 83 luminaires removed no longer cost purchase, installation, electricity or maintenance for the whole life of the installation. Other operations of the same kind are detailed in our projects.
Financing: what changed in 2026
The order of 23 February 2026, in force since 25 February 2026, abolished the CEE sheets BAR-EQ-110, BAT-EQ-127 and IND-BA-116. Direct consequence: there is no longer a standardised energy savings certificate (CEE) bonus for indoor relamping. Any commercial proposal that still announces a CEE bonus on indoor lighting is wrong and should be set aside.
Outdoor lighting renovation remains eligible through sheet RES-EC-104, revised by the order of 24 November 2025. Road, car park and site surroundings projects therefore keep a financing lever, with outdoor and road lighting luminaires compliant with the NF EN 13201 series.
For indoor lighting, the current levers lie elsewhere. Long-term leasing over three to five years most often lets the monthly saving cover the instalment, without tying up cash. Calculating the payback time zone by zone makes it possible to treat first the areas that consume the most, those that run the longest. Finally, several related items remain eligible for CEE: building management systems, destratification and variable speed drives. These three items are handled in the same project, with the same costing.
The six figures to gather before signing
- The real operating hours, zone by zone, not a site average.
- The measured installed power, not the theoretical power of the original plan.
- The real price per kilowatt hour, standing charge and taxes included.
- The illuminance levels measured with a lux meter, on the task areas.
- The number of points and their height, which determine the cost of access.
- The history of failures over the last three years.
With these six pieces of data, comparing two offers becomes possible. Without them, you compare unit prices, which tells you nothing. This is also the stage where controls are decided: presence detection, dimming, zone management. A luminaire switched off or dimmed for half of its operating time halves its consumption, and control and safety solutions often weigh more over ten years than the choice of the luminaire itself. All the ranges can be browsed in the Rexylum professional LED luminaire catalogue, our brand, which we supply and have installed.
Costing your installation
The full cost of lighting is calculated before the purchase, not after. The audit and the photometric study are free, site visit and 3D modelling included: we are paid on the solution we supply and have installed, not on the engineering. Contact us to get the item-by-item calculation for your site, with the number of points needed, the payback time by zone and the associated financing plan.
