Challenging the checkbox mindset in office lighting design, Miles Cantley, Innovation Director at Mount Lighting, brings a design-centric perspective to how we apply CIBSE LG7 (or Lighting Guide 07).
In the world of light and lighting for modern workplaces, CIBSE Lighting Guide 7 has become the go-to reference for lighting designers, consultants, and specifiers alike. And for good reason – it’s a robust, well-researched, longstanding guide (the clue is in the name) that brings structure to what can often be a subjective discipline.
But there’s a growing issue I keep seeing in specifications and project meetings: we’re treating the guide like a rulebook.
I’ve lost count of the number of electrical consultants I’ve come across who wield LG7 like a headmaster’s cane – pointing sternly to uniformity ratios, UGR values, illumination levels, and luminance limits with the unwavering certainty of a rule enforcer. Tick boxes get checked, numbers get met, and everyone sleeps soundly knowing the lighting specification complies.
But compliance doesn’t equal good lighting design. And obsessing over the numbers without understanding why they’re there is like trying to cook Michelin-star food by reading ingredient lists without tasting the dish.
LG7 Is a Guide, Not a Rulebook
The LG7 guide is a great document. It’s built on years of research and practical experience. But it was never meant to be treated like a rigid code. It’s there to provide principles and considerations – not to remove the need for thinking.
Too often, I see office environments lit with schemes that are technically compliant but divorced from the office space’s purpose or people. Just because the average UGR is 19 doesn’t mean the illumination is right for that open-plan task area. Just because the lighting levels hit the sweet spot on paper doesn’t mean it feels good to work in.
LG7 even says it itself – context is everything. Task, user, layout, natural light, operational energy, technology – all of it should shape decisions. The guide is there to support flexible, functional, and yes, human-centric task lighting schemes. It’s not a bureaucratic checklist for ticking boxes.
Context Modifiers: The Missing Piece
Here’s what gets overlooked in the race to hit the magic numbers – context modifiers.
Glare ratings mean very little if you don’t understand the space’s geometry, surface reflectance, or even where people are sitting. Uniformity targets are great, but what about layered lighting, visual hierarchy – or how light supports focus and wellbeing in the task area?
Lighting designers need to balance precision with purpose. This isn’t just about metrics. It’s about using light and lighting to foster productivity, reduce discomfort, and even reduce energy use through smarter control strategies and adaptive systems.
In short, lighting design mistakes often stem from over-indexing on technical compliance without taking a beat to ask, “What’s this space actually for?”
That’s how you end up with sterile, uncomfortable environments that look perfect on a Relux plot and feel completely off in person.
It’s Time to Get Real
I’m not saying throw the guide out the window. CIBSE LG7 is valuable – very much so. But we’ve got to stop treating it like a strict rulebook and start using it the way it was intended: as a foundation for intelligent, contextual decision-making.
So next time someone pings you a spec demanding UGR < 19 with uniformity ≥ 0.6 across the board – take a moment. Ask questions. Understand the office space. Then design lighting that works, not just lighting that complies.
Because great office lighting design is never just about the numbers. It’s about people, performance, and how the space feels – all while keeping an eye on energy use and operational energy goals.
Ready to move beyond box-ticking and create lighting designs that truly work for workplace and the people in it? Contact us today.