Why Should We Care about Natural Light?​

Created By RISC | 6 months ago

Last modified date : 6 months ago

Natural light is a dear friend who’s been with us since we first opened our eyes. But we now seek to avoid it out of concerns over heat and radiation.

Sunlight produces heat and radiation but we cannot live without in our daily lives. Natural light aids in vision, waking, sleeping, and our lifestyle. Light directly affects health, aiding both physical and mental recovery as well as helping with emotional disorders. A study found that more time outdoors in natural light boosts work effectiveness.​

The International WELL Building Institute (IWBI), the WELL Building Standard developer, and the U.S. Green Building Council, the LEED standard creators, aim to bring natural light into usable spaces within buildings by focusing on the value of receiving natural light, entering in 2 ways:​

• To meet annual sunlight exposure (ASE) standards, buildings must get over 1,000 lux of natural light for 250 hours per year and not exceed 10% of total area. This is an ideal ratio for admitting natural light into the structure that strikes a balance between obtaining adequate sunshine for health and regulating heat within the building.​

• Spatial Daylight Autonomy (sDA) refers to the proportion of an area receiving enough light in a year. This is achieved by exposing at least 50% of working hours to natural light of at least 300 lux for 55%, 75%, or 90% of the total area. The more natural light that reaches the space, the higher the score from the criteria (USGBC, 2018).​

We can observe that neither value has a stable maximum brightness value since the activities in the area have variable requirements for maximum brightness, such as working hours throughout the seasons when light does not reach the same areas. Therefore, the value is set to total hours instead.​

In addition, IWBI requires 6-7 meters of workstation close to the window, which accounts for 30% of the work area on each floor. This is in line with the observed lighting simulation results. At distances greater than 6-7 meters, the brightness in the area falls below 300 lux, which is deemed insufficient for operation and must be supplemented with artificial light.​



The lighting model on 21 December 2024 at 3pm shows the importance of choosing the location for use of space on each side of the building. Inside the northeast room, there is an average light value of 1,078 lux, with no sunlight shining into the room. Rooms in the southwest were the rooms with the highest average overexposure of 11,229 lux, which was accompanied by hot sunlight. The southwest should therefore be avoided as a regular work area.​

Building design has a considerable impact on the occupants' exposure to natural light. Furthermore, it is an important issue that requires computer simulation models to determine the accuracy of ASE and sDA values early in the design process to provide space for building users to receive adequate natural light.​

We now know the value of sunlight. So, don't forget to shift the table and chairs to receive some natural light.​

In the next post, we'll look at what happens if we face a poor, inappropriate light that is bad for us.

Find out more about light and simulations to evaluate its efficiency from Research & Innovation for Sustainability Center (RISC) at RISC Well-Being Facebook Inbox, or RISC LINE Official: risc_center.​

Story by Wacharakorn Maneechote, Sustainable Designer, Well-Being Research Integrations, RISC