In 2013, a RIBA commissioned survey revealed that one in five homeowners were unhappy with the amount of natural light in their homes. This lack of sunlight can have a significant impact on the health of occupants and often means lights are kept on for longer, wasting energy. But how can we avoid this issue? The answer is effective daylighting.
Daylighting is the practice of installing windows, or other openings such as rooflights, and reflective surfaces within buildings to allow natural light to enter and spread through rooms and internal spaces.
There are several design considerations for daylighting provision, including:
- window size, quantity and layout;
- room layout and depth;
- internal finishes, such as reflective surfaces and interior decoration; and
- positioning of exterior obstructions, such as other buildings or trees.
These elements must be factored within the wider design objectives for a building — such as its energy efficiency.
We recently commissioned Peutz BV to assess how different wall insulation specifications can affect natural light levels within a building. The resulting white paper is available for download now. It shows how, by installing higher performing insulation, wall and sill depths can be kept to a minimum, helping to improve internal daylight levels without compromising fabric performance.
There is a significant and growing body of research on the health benefits effective daylighting can provide across a range of sectors. For example, a recent paper from the BRE concluded that improving patient access to natural light in hospitals can lead to “a reduction in the average length of hospital stay, quicker post-operative recovery, reduced requirements for pain relief, quicker recovery from depressive illness and disinfectant qualities.”
Many of the health and wellbeing benefits associated with proper daylighting provision are highlighted within BS 8206-2: 2008 (Lighting for buildings. Code of practice for daylighting). They include:
- a regulated circadian system, which controls the body’s sleeping and waking cycles and core temperatures with the external day and night cycle;
- reduced symptoms of Seasonal Affective Disorder (SAD), such as depression, low energy, tiredness, increased appetite and weight gain;
- maintenance of healthy levels of vitamin D, positively linked to healthy bones;
- reduced amounts of bacteria and virus associated with respiratory infections common in winter; and
- a positive impact on mood for those who spend a lot of time indoors.
The health and wellbeing benefits of effective daylighting are also now recognised within many of the top building performance standards. Light is one of the eight key concepts within the increasingly popular WELL Building Standard with marks awarded for Right to Light, Daylighting Fenestration, Solar Glare Control and Circadian Lighting Design.
Good daylighting provision can also directly contribute towards the award of two credits within section Hea 01 of the latest BREEAM assessments. The standard recognises that effective daylighting can also reduce “the need for energy to light the home” as electric lights can be kept off for longer, helping to cut energy bills.