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Thursday 10 August 2017

Seven amazing facts about daylighting, health and wellbeing

It’s widely accepted and generally understood these days that sunlight plays a vital role in human health and wellbeing. But going beyond the generalisations and looking at some of the actual data published by academics and respected experts across the world, there are some amazing facts coming to light.
Here are seven, to get you started.

Daylight makes people happier and reduces stress

Countless studies* have indicated that daylight enhances mood and energy through the release of endorphins (hormones which have a euphoric or painkilling effect). This means that daylighting in buildings literally contributes to the happiness and wellbeing of occupants. This should be a critical factor in informing the design and specification of buildings across all sectors.

Access to daylight enables patients in hospitals to be discharged earlier

A study published in 2012, found that ‘A significant relationship appears to exist between indoor daylight environments and a patient’s average length of stay in a hospital. In the brighter daylit areas, average length of stay was 16%-41% shorther than in areas relying heavily on artificial lighting.

Daylight acts as an analgesic or pain killer

A study of patients undergoing spinal surgery, published in 1995, stated that ‘Patients were assigned postoperatively to rooms on either the bright or dim side of the hospital unit. Those on the bright side received 46% more natural sunlight and required 22% less analgesic medications during their hospitalization. These patients also experienced a 21% reduction in analgesic medication cost compared with patients on the dim side.’

Daylight acts as a disinfectant

Experiments undertaken in the USA and the UK between 1941 and 1944 demonstrated the extraordinary and remarkable effectiveness of daylight in killing bacteria. Even diffuse daylight passing through two layers of glass from a north window was found to be highly effective in killing streptococci bacteria within 13 days, with the same strain surviving in the dark, at room temperature, for 195 days.

Daylight reduces depression among patients with bipolar disorder or seasonal affective disorder (SAD)

One study found that bipolar depressed inpatients in east-facing rooms (exposed to bright light in the morning) stayed an average of 3.67 days less in the hospital compared with similar patients who stayed in west-facing rooms. Many studies have been carried out into this phenomenon and all offer broadly similar conclusions.

Daylight helps to reduce agitation among elderly patients with dementia

Elderly residents in facilities with low light levels have been shown to display higher agitation levels – and exposure to bright morning light reduces agitation among elderly patients with dementia. When elderly patients with dementia were exposed to 2,500 lux for 2 hours in the morning for two 10-day periods, their agitation reduced. Patients were significantly more agitated on non-treatment days.

Daylight helps students to perform more effectively

Research into daylighting in schools carried out by a leading organisation in the USA, demonstrated a 25% improvement on test scores in daylit classrooms over classrooms with the least daylight. This result has been corroborated by UK studies and has informed the Government’s Building Bulletin 90, ‘Lighting Design for Schools’. In Canada, a study analysed 21,000 students’ results and discovered that sunlit classrooms resulted in students performing 20% faster in maths tests and 26% faster in reading tests.

These provide just a glimpse into the huge bank of research carried out into this fascinating subject in recent years.
Here at Lareine Engineering, we can provide a wealth of experience in designing with daylight, to maximise these beneficial effects, whilst taking into consideration aesthetic considerations and the needs to control glare and overheating.

* Further reading:

Research referenced by the Building Research Establishment and published on

An Introduction to Daylighting with Rooflights - RIBA approved CPD Seminar by NARM, available on-line at: