The power of light to change your world for good
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Energy savings and human-centric lighting, measuring daylight and training your brain…

People v planet?

Delivering enough artificial light to meet the recommended level for circadian entrainment without glare uses up to 100% more energy than the legal minimum and demands more fittings – Energy impact of human health and wellness lighting recommendations for office and classroom applications

Add the cost and carbon footprint of the upgrade.

In tight financial times with net zero target to meet. Who can afford that?!

New studies show how you can have your (green) cake and take care of your body clock too…

If you get outside enough, your body clock needs less artificial light to stay on track – for most of the year at least. Dim light during the day makes you up to 70% more sensitive to light after dark The human circadian system adapts to prior photic historyAnother study suggests that if you stack up the photons during the day, you can even read a book on your computer in bed and still get a good nights’ sleep Two hours of evening reading on a self-luminous tablet vs. reading a physical book does not alter sleep after daytime bright light exposure.

But with the best will in the world, you aren’t going to be outside all day!

Nick Gentile’s review finds up to 50% energy savings from five simple strategies with no loss in performance or satisfactionImproving lighting energy efficiency through user response.

  1. Automatic dimming cuts energy use by 20% in transition zones without the user noticing the change.
  2. Automatic blind and shade control (after initial curiousity, the controls were used an average of once every 20 days…)
  3. Set a lower range for manual dimming – those who need more will turn up the levels, while everyone else opts for a ‘medium’ setting, regardless of the range.
  4. Easy controls that are hard to miss – simply adding a red frame to the light switch in a public toilet cut energy use by two-thirds.
  5. Nudge users to do the right thing –  a simple sign cut energy use by 16.8%, a live monitor cut it by over 20%
  6. Give the end-user control –  default off with a manual-on (compared to automatic on) saved 17.8% on the electricity bill: half of participants preferred natural daylight and kept the lights off- Impact of occupant autonomy on satisfaction and building energy efficiency


Measuring the rainbow.

Millions of people won’t go outside today – perhaps including you! So what are the qualities – and quantities – of artificial light we need to cope with this indoor life? it’s a hotly debated topic, including the ole of wavelengths on the edge of the visible spectrum. All agree that daylight (and of course darkness) is the gold standard for our diet of light This excellent editorial offers an overview of current measures and innovations in daylight calculations with links to some fascinating papers – Editorial: Daylight and illuminance measurement


It’s train your brain day in the USA

Jim Kwik is my go-to for down to earth tips to turbo-charge your ability to learn – and enjoy the process too. Check out this video – Make Learning Fun, Fall In Love With Your Brain, And Unleash Your Amazing Genius

Five key takeaways – 

  1. Prime your brain – simply believing you can learn is a great place to start
  2. Optimise your environment – a space that is comfortable, uncluttered and uplifting will help you to get down to work
  3. Maximise your study session – choose your time of day, be clear what you’re trying to learn and assemble the tools you need in advance.
  4. Take brain breaks – a stroll outside could give you the perspective you need to see a topic in a different light
  5. Remember to review – teaching someone else what you know is the best way to see the gaps in your knowledge -and get the information ready to upload into your long term memory while you sleep.



I’m leading an CPD session on circadian lighting hosted by Atrium in partnership with Design Lighting, LMPG and LumenPulse on the 21st of November in London. That’s the evening before Light23. Places are strictly limited so please get in touch if you would like to join and I’ll share a link – it would be wonderful to see some of you there!

Get in touch!