The psychological effects of lighting: Guidance for designers on understanding how light affects mood and well-being

In recent years, we’ve become more conscious than ever of how our surroundings influence our mental and emotional well-being. With much of our time spent indoors, the importance of lighting in shaping our psychological state has come to the forefront.
Lighting has a profound effect on how we feel, think, and behave, which has a real impact on commercial interior designers. It doesn’t matter if you’re working to create a calming ambience in a restaurant or energising a workspace to boost productivity, getting the lighting right is crucial.
And understanding the psychological effects of lighting is where this starts. By specifying lighting systems correctly, we can transform how we design and use interior spaces, making them not only more aesthetically pleasing but also conducive to better mental and emotional health.
How does lighting affect our brains?
Lighting impacts our brains in fundamental ways. It affects how we perceive spaces, influences our mood, and even dictates our sleep patterns. Let’s look at a few of the factors that play a part in shaping this:
The role of circadian rhythms
Our bodies follow natural cycles known as circadian rhythms, which govern our physical, mental, and behavioural patterns over a 24-hour period. These rhythms are primarily influenced by light and darkness and regulate essential functions like sleep, hormone production, digestion, and energy levels.
The suprachiasmatic nucleus (SCN) in the brain acts as a master clock, receiving signals from the eyes and adjusting our internal systems accordingly. Natural light helps maintain synchrony between our biological clocks and the environment. However, as we spend more time indoors and are increasingly exposed to artificial lighting, these natural rhythms can become disrupted.

According to research published in Sleep Medicine Clinics, unnatural light exposure can lead to altered sleep schedules, reduced concentration, and diminished energy levels. In practical terms, this means that poorly designed lighting schemes can have a direct, negative impact on our well-being, emphasising the importance of aligning artificial lighting with natural circadian rhythms.
The impact of overly bright lighting
Bright lighting, especially when overly intense or at odds with natural daylight patterns, can heighten alertness and boost mood temporarily. However, prolonged exposure to bright, artificial light at inappropriate times (such as late in the evening) can lead to sleep disturbances and increased stress levels.
For example, stark, cool-white lighting might feel invigorating in a gym or retail environment, but in a lounge or relaxation space, it can cause discomfort and irritability. Getting the balance right between brightness and warmth is essential for creating spaces that support both productivity and relaxation.
Flexible lighting systems: Using brightness controls to maintain physical comfort and mental well-being
Research from Environmental Psychology shows that the brightness (lux level) of lights has a direct impact on a wide range of things. Bright interior lighting is known to boost alertness and energy, making it great for workplaces. It can also heighten emotions and intensify decisions, both positively and negatively. Used correctly, bright lighting improves mood and supports mental health, but overexposure can disrupt sleep and increase stress, so balancing brightness is key to getting the benefits without the drawbacks.
At Unibox, we recommend dimmable and colour-tunable LEDs for specific lighting applications (which users can adjust with a range of different controls, e.g. DALI, Casambi, etc.) to aid the functionality of interior lighting schemes.
How to customise lighting for comfort and efficiency
In settings like hotels or office spaces, lighting systems can be programmed to change brightness levels at different times, helping occupants stay energised during the day and relaxed in the evening. For instance:
- Morning: Bright, cool light simulates natural daylight and boosts alertness. The ideal colour temperature is between 4,000K and 6,000K, which is the colour temperature of natural sunlight.
- Afternoon: Balanced, neutral lighting helps maintain focus without causing strain.
- Evening: Soft, warm lighting signals winding down and promotes restful sleep.
Using things like dimmer switches or varied lighting schemes that feature a range of different light sources (ambient, task, accent, etc.) can help designers achieve interior environments that meet the needs of their users all day long.
The colour temperature of lighting: Creating the right atmosphere
Lighting temperature is measured in Kelvin (K) and plays a crucial role in setting the mood and functionality of a space. Warmer lighting, which appears more yellow or amber, generally has a lower Kelvin rating (around 2,000K to 3,000K), while cooler lighting, appearing bluish or white, ranges from 4,000K to 6,500K.

Warm light for comfort and relaxation
Warm lighting evokes feelings of comfort and intimacy, making it ideal for environments where relaxation is the priority. It’s commonly used in hospitality settings, such as hotel lounges and restaurants, where creating a welcoming, tranquil atmosphere is crucial.
For example, ambient lighting in a fine dining restaurant might use lower Kelvin temperatures to enhance a cosy, intimate experience, encouraging guests to unwind and enjoy their meal.


Cool lighting for productivity and focus
Cooler lighting is associated with increased focus and alertness. It’s commonly used in workplaces, retail spaces (like supermarkets), and educational settings to promote concentration and efficiency. Bright, cool-white LED lighting can help invigorate employees, making them feel more alert and capable of tackling demanding tasks.
Retail environments, too, benefit from cooler lighting, as it can create a vibrant and dynamic atmosphere, encouraging customers to stay active and engaged. For instance, bright, crisp lighting in a sports store makes products look fresh and energising, motivating customers to explore the space.
There are no hard and fast rules to lighting, though, only suggestions. For example, certain retail spaces (especially those of luxury brands) may choose dimmer, warmer lighting to reinforce feelings of exclusivity and opulence.
Strategic considerations for lighting designers
We know that lighting designers and specifiers have a responsibility to ensure the well-being of the people who use their spaces, so just thinking about the psychological effects of interior lighting is only part of the story.
To have a true impact, we need to put theory into practice – applying what we know about the relationship between lighting and human behaviour and experience. This means asking questions about how (and by whom) the space will be used.
Here are our tips for choosing lighting systems that deliver on both form and function:
- Consider the purpose of the space: Adjust lighting schemes according to whether the aim is to relax, concentrate, or feel energised. The wrong lighting can set the wrong tone from the moment someone enters, making the space unsuitable for use.
- Layer lighting for flexibility: Use a combination of ambient, task, and accent lighting to create depth and allow users to adjust light levels easily to suit needs. Pairing ceiling lightboxes with wall-mounted LED signage and recessed LED lightbars provides a dynamic, flexible solution.
- Use adjustable systems: Specify lighting controls that can adapt brightness levels based on the time of day and activities. For example, a hospitality venue that operates as a cafe during the day and an intimate restaurant at night will need two very different lighting ambiences.
- Prioritise user comfort: If people are uncomfortable, they won’t want to hang around…regardless of whether it’s an office, retail space, restaurant, or otherwise. Proving this, a study published in the Journal of Building Engineering found that women tend to prefer lower illumination and correlated colour temperature than men, which tells us how we can tailor lighting based on target demographics.
- Don’t forget about natural light: Where possible, harness natural light alongside artificial light! Natural light sources help to maintain circadian rhythms and promote overall well-being. If spaces don’t have access to natural daylight, you can specify LED systems with a particular colour temperature to replicate its effects.

Lighting systems with Unibox
At Unibox, we take a holistic approach to lighting design, recognising that the right solution enhances visual appeal and improves well-being. Our bespoke luminaires are engineered to give you complete control over brightness and colour temperature.
We work closely with architects, interior designers, and commercial planners to develop lighting systems that meet both functional and emotional requirements. Whether you’re designing a serene hotel lounge or a dynamic retail space, our lighting solutions are crafted to deliver the desired psychological effect.
Contact us to learn more about our interior lighting systems and bespoke LED solutions.