Benefits of natural light
Rooflights save energy and reduce carbon emissions
The primary reason for including rooflights is to provide a bright, naturally lit interior and reduce the requirement for artificial lighting. Daylight has many advantages over artificial light - not least the fact that it is a completely free, unlimited natural resource. Whilst artificial light is essential, it’s provision uses a lot of energy, so reducing the requirement will dramatically cut energy use, and the CO2 emissions which result from this.
There has previously been a widely held view that whilst rooflights are an excellent way of bringing the many benefits of natural light into a building, their poorer insulation value allowed more heat to escape than the rest of the roof structure, increasing the running costs of the building. Recent research has confirmed this view is no longer accurate, as modern rooflight design has resulted in significant gains in insulation value in recent years.
Design parameters for the building, such as temperature set point, hours of occupancy, and internal gains, can all alter the effect that rooflight area can have on the total energy requirements of heating, cooling and artificial lighting systems.The savings in total energy costs and carbon footprint therefore vary from building to building, but are usually found to be positive as rooflight area increases, often up to 20% of the roof area.
More information about designing with rooflights to save energy can be found at www.narm.org.uk/home/documents.html.
Rooflights provide healthier and more functional internal environments
Daylight is an essential natural asset. For those of us living in temperate Northern climates, the beneficial effect of sunlight is easy to recognise; a couple of sunny days seem to lift everyone’s spirits. Research also shows that suicide rates are considerably higher in parts of the world where daylight is very limited for significant parts of the year. There is also a growing body of evidence to suggest that buildings enjoying high levels of natural light are literally more successful than those more reliant on artificial light. In all environments the eye and brain functions respond better to natural light, so people perform better. Natural daylight promotes a sense of wellbeing amongst building occupants and rooflights achieve this without the potential distractions created by views through vertical windows. Where vertical windows do not exist, rooflights provide occupants with beneficial ‘daylight contact’.
Rooflights can provide specific benefits in a wide range of applications:
Education
Research demonstrates a clear correlation between classrooms with good natural light and improved student performance and even attendance. This is because in natural light children concentrate better so are more focused and less easily distracted. Some studies suggest that health is also enhanced, helping to explain the improved attendance. Further specific information about lighting design for schools is contained in the Government’s Building Bulletin 90.
Health
In the UK we are used to hearing of SAD, Seasonal Affective Disorder, a clinically diagnosed condition in which the lack of sunlight in winter makes people feel ill. Natural light helps people to feel better but it can also aid the healing process. In hospitals, studies have proven that the recovery rate of patients is accelerated where levels of natural light are increased.
Business & retail
Daylight improves concentration so that working environments, be they factories or offices with natural light, tend to achieve increased productivity. Research into retail environments suggests that in many situations sales tend to be better in naturally lit locations; colours are more vivid and true, making goods appear attractive and encouraging customers to spend more time in these areas. A number of the UK’s leading retail organisations include large areas of rooflights in specifications for all new build projects to ensure a high percentage of evenly distributed natural light within the interior.
Recreation
People like bright naturally lit environments, evidenced by the huge popularity of domestic conservatories and sunrooms. It is therefore logical that in their leisure time people prefer facilities enjoying high levels of daylight. Most sporting and recreational facilities today try to maximise natural daylight in recognition of this.
