What exactly is good quality commercial lighting?

Originally published in arc magazine's October edition.

Good lighting is not something people often notice immediately; our attention generally gravitates to architecture and interior design – unless, of course, you are a lighting designer.

Indoor lighting is a subtle yet pertinent element that complements interior design. Like a person in a nice outfit, we notice the person first and the outfit’s ability to enhance their beauty second. The effect of lighting goes beyond creating aesthetic spaces and allowing us to see. Light has been integral in shaping the trajectory of evolution and acts as a cue for activity and rest.

In contemporary life, the average office worker spends 60-70% of their lives in the office thereby creating a responsibility for developers and employers to create workspaces that are healthy and encourage productivity. Light is proven to have a huge influence on our health and wellbeing, and as a result, lighting design cannot be left behind amongst the plethora of design considerations for a healthy office.

Gone are the days when offices were fitted with energy-guzzling, lackluster tube lights that stayed at the same intensity for hours on end. They are not sustainable, nor healthy. Yes, our surroundings should be well lit, however, lighting should take advantage of the benefits of natural daylight and adapt itself accordingly. Such daylight design strategies involve relying on the available natural light alongside electric lighting. The trend is intuitive: when light is available externally, the reliance on electric lighting should decrease and in the darker hours of the day we shift to artificial lighting. This ensures spaces are well lit throughout the workday in a sustainable fashion as there is a lower energy need when natural light is available.

It might seem unlikely that such a minor design choice could have a significant influence on sustainability. Cundall’s Manchester and London offices conducted a study as part of the Building Energy Exchange’s Daylight Hour 2023 campaign which calculated the energy saved when the lights were turned off for an hour. Turning off the lights for an hour in the Manchester office saved 9.19kWh, and in London it saved 28.32kWh. This equates to 2,307kWh and 7,108kWh per year respectively. Clearly, reducing the intensity of light for a few hours when it’s bright outside can have a considerable influence in reducing energy.

Employers may often be under the perception that keeping an environment bright throughout the day allows people to stay ‘awake’ and hence productive. However, how ethical is it to keep someone’s environment ‘well-lit’ for eight hours continually during each day of the working week?

Natural light, and its colour and intensity, varies throughout the day, and helps in the alignment of circadian rhythms. Cooler light colour temperatures are produced when the sun is shining at its brightest around noon, while warmer colour temperatures are emitted during sunrise and sunset. This influences energy levels through the day – with unconscious cues for staying active and resting.

In a workplace environment, where lighting is bright and constant, a lack of variation can negatively impact wellbeing, for example through burnout. To combat this, circadian lighting design strategies, where light intensity and colour temperature changes according to the time of day, are better for occupiers' wellbeing. A lighting design strategy that alternates between cooler and warmer light colour temperatures can essentially imitate daylight by creating an outdoor light environment indoors.

Cundall’s Birmingham office was designed to centre around a spiral helical timber staircase that is fitted with twelve spotlights which follow the path of the sun through the course of the day. The result is a subtle change of shadows cast by the staircase around the office throughout the day – a good example of artificial lighting being used to imitate daylight.

The International WELL Building Institute has devised guidelines for lighting design to meet standards of comfort and wellbeing for occupants. The guidelines address the initial necessities of office lighting such as light that allows people to read and see clearly. Alongside that are considerations for ensuring people remain healthy, such as circadian lighting design strategies. When it comes to office lighting, striking the balance between productivity, wellbeing and sustainability is an important consideration. Ultimately, ensuring daylight is utilised to its maximum ability whilst simultaneously imitating patterns of daylight indoors seems a reasonable ideology for lighting designers. Using light colour temperature variations is a valuable tool to achieve this.

In terms of putting sustainability at the heart of lighting design, the best advice we can give as lighting designers is to do it right the first time and you won’t have to do it again. Once the occupants’ needs are satisfied and their wellbeing has been improved by a good lighting system, they are less likely to need replacing continually. The objective of investing in ‘good quality’ lighting is to ensure that we are designing sustainably, saving energy, and saving money as well.

Moreover, good lighting schemes must account for future proofing. In recent times, we have seen massive changes in how office spaces have been adapted to staff needs. The acceleration of hybrid working has created a new realm of opportunities for office spaces, with the introduction of breakout spaces, wellness rooms and collaborative workspaces amongst other things. When it comes to lighting, flexible or modular lighting systems which can be easily configured to adjust to changes in office areas or layouts can be a sustainable alternative.

With workspaces increasingly focused on staff wellbeing, elements such as indoor air quality and the creation of greener environments for mental wellbeing have been in the spotlight. However, lighting design must not be forgotten in the much-required push towards a healthy and sustainable office. Wellbeing and sustainability in lighting design need to work in tandem to create a holistic lighting system. Lighting designers have a responsibility to adapt and put people and their wellbeing at the heart of our design decisions, because ultimately, we are creating these spaces for people.