The Carbon Footprint of a Luminaire: Are we Fixating on the Wrong Bit?
The commercial lighting industry talks a lot about sustainability. And that’s a good thing. The problem is, however, where we are spending our effort.
Take a look at the full life-cycle carbon footprint of a typical commercial light. Manufacturing usually accounts for 8-10% of total lifetime emissions. Independent lifecycle analyses back this up. Peer-reviewed research has shown that, for most luminaires, the majority of carbon emissions occur during the use phase rather than manufacture, with operational energy overwhelmingly dominating lifetime impact. This does vary based on lighting type and usage profile amongst other assumptions, but the order of magnitude is relatively consistent. The remaining 90% or so is then dominated by use-phase energy consumption, along with smaller contributions from transport, installation, maintenance, and end of life.
And yet, as an industry, we’re disproportionately focused on shaving carbon emissions out of the manufacturing phase. It’s understandable, but also not necessarily intelligent.
Manufacturing Carbon
Carbon emitted during the manufacturing phase is often easy to measure, audit and report compared to once the product has left the factory. This also means it can be easier to put measures in place to reduce emissions such as recycled materials, greener suppliers or packaging and transport improvements.
But let’s be clear about impact. You can halve the embodied carbon of a luminaire during the manufacturing phase but still barely move the needle on its lifetime footprint if the light is poorly specified, poorly controlled, or over-lit for the next 15 years. In other words, we are choosing to optimise the bit that is easiest to control, not the bit that matters the most.
The dominant carbon driver for most commercial lighting is how much energy it consumes over its operational life. Whilst UK commercial lighting manufacturers influence some of this, they don’t own it. Specifiers decide light levels and layouts. Contractors decide how faithfully controls are installed. End clients, ultimately, decide whether energy-saving controls are enabled, overridden or ignored entirely.
A Thought Experiment
Imagine two different luminaires.
Luminaire A
Ultra-low embodied carbon
Manufactured locally using recycled materials
Installed in an office with no controls
Runs at full output, 12 hours a day, five days a week, for 15 years
Luminaire B
Higher embodied carbon
Manufactured conventionally
Installed with occupancy sensing, daylight linking, and sensible light levels
Effectively runs at 40-50% equivalent full load over its life
Which one has the lower lifetime carbon footprint? Luminaire B. And yet, Luminaire A is the one more likely to be added to a specification based on its sustainability credentials.
A Smarter Approach
The construction industry is under pressure to decarbonise quickly, and effort has to be proportional to impact. Focusing heavily on the 8-10% while underplaying the 90% is a strategic error and creates a false sense of progress. We can hit embodied carbon targets, publish EPDs and still deliver buildings that waste energy every single day.
But, this isn’t an argument against reducing manufacturing carbon. It’s an argument for balance. A more intelligent industry response would firstly be to keep reducing embodied carbon but stop pretending it’s the main event. More emphasis should be placed on specification quality, ensuring the right product, right output and right application is always prioritised.
Smart controls such as Mount Lighting’s Casambi wireless lighting control should be treated as non-optional infrastructure, not an upgrade. Commercial lighting without effective control can be a carbon liability, regardless of how sustainably it is manufactured. This is also why measuring performance in use is important. If we don’t know how fittings are actually performing once installed, then improvements cannot be made.
UK commercial lighting manufacturers like talking about reducing manufacturing carbon because it is tidy, contained and easier to manage. But if we genuinely care about reducing the carbon footprint of lighting, we need to spend less time polishing the 10% and more time wrestling with the messy 90%. That means deeper engagement with designers, contractors and end clients. It’s harder, less controllable and won’t fit as neatly into marketing graphics, but it’s where the carbon actually is.
Ready to tackle the 90%, not just polish the 10%?
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