When I remodeled an office in Manchester last year, the first thing I didn’t do was add plants or change the colour scheme. I assessed where the windows were located and how much actual daylight was entering each workstation. Everything else was based on that assessment.
Biophilic design is based on the fundamental principle of providing sufficient natural daylight to occupants. While many elements of biophilic design can be replicated or faked (e.g., adding plants, painting walls green, using nature-inspired materials), you cannot replicate daylight. Without sufficient natural light, the other elements of biophilic design may feel superficial.
I have been designing interior space for 12 years and have found that natural daylight is what distinguishes living spaces from lifeless ones. The literature provides strong evidence to support this observation.
What Natural Light Does (The Science)
Research has shown that natural daylight exposure:
- Synchronizes the body’s circadian rhythm, resulting in improved sleep quality and reduced anxiety in healthcare and office settings; this is not about aesthetic appeal – this is about how the body operates.
- Improves recovery rates in surgical patients by 8.5% and reduces pain medication use by 22% compared to patients in rooms without windows. Meta-analyses provide evidence of this relationship in hospitals.
- Reduces diastolic blood pressure, stress hormones, and improves cognitive performance and memory. The physiological response to natural daylight is different than the response to artificial light.
- Improves productivity and focus with 15% greater employee wellbeing, 8-15% increased productivity and 13% greater creativity. Dynamic lighting systems increase workers’ ability to concentrate by 6-15% and reduce absenteeism.
These findings are significant. A 15% increase in productivity over several months or years equates to thousands of pounds saved in labour costs.
Employees with nature views take 11 fewer sick days annually (57 vs. 68 hours/year).
Reducing Energy Consumption Through Daylighting Strategies
Daylighting strategies combined with electric lighting can dramatically reduce energy consumption, which is beneficial for organisations looking to achieve net zero energy usage and improve occupant comfort.
You can save electricity (and therefore money) by relying on natural light to illuminate your space. Additionally, energy savings benefit the environment.
Most Spaces Do Not Receive Enough Natural Daylight
Unfortunately, I find myself assessing numerous offices and residential spaces that do not receive adequate natural daylight due to various factors including:
- Poor orientation of the building
- Small windows or too few windows
- Other buildings obstruct daylight
- Layouts with interior rooms with no external walls
London is particularly challenging in terms of receiving adequate natural daylight due to the prevalence of old Victorian conversions and deep apartments with internal bedrooms with minimal daylight exposure.
However, when you understand the hierarchy of light-related issues, you can determine how to best utilise your resources to maximise daylight in your space.
Evaluating Your Lighting Conditions
Understanding the conditions you are currently experiencing in your space is essential prior to developing a solution to address your light issue.
| Light Condition | Definition | What It Means | Possible Solutions |
|---|---|---|---|
| Excellent (South/West-facing, unobstructed) | 6+ hours of direct sunlight | Maximum light penetration, potential heating/cooling problems | Use light-diffusing treatments for heat control, maximise window size |
| Good (East/North-West, partially obstructed) | 3-6 hours of direct or 6-8 hours of diffused sunlight | Natural light available to support a variety of activities, natural rhythm | Clean windows, eliminate obstructions, use light-coloured finishes to reflect natural light |
| Moderate (North-facing, interior side of building) | 1-3 hours of diffused light or bright indirect | May not be suitable for tasks requiring high amounts of natural light, requires additional supplemental lighting | Consider installing a skylight, install mirrors to reflect natural light, and/or install quality artificial lighting with circadian benefits |
| Poor (Interior rooms, deep floor plates, shading) | Less than 1 hour or no direct/diffused light | Will not be able to rely on natural light as primary source, will need artificial lighting to compensate | Install a skylight (structural), install light tubes (to reflect natural light), and/or install quality artificial lighting with circadian benefits |
Most London homes fall into either “Moderate” or “Poor” categories. Lack of daylight in your home is not a failure on your part – it is simply a product of urban reality.
Maximising Natural Light (What Really Works)
Clean windows. Honestly. Dirtied windows impede 20-30% of available natural light. I once visited an office that cleaned the windows as their first step to improving daylight in their space – immediate results.
Remove obstructions. Curtains, furniture, clutter that block windows. Remove the curtains if you do not need them for privacy. If you do need to keep the curtains, choose sheers or light-coloured ones that allow natural light to pass through rather than block it.
Position furniture to optimise daylight. Do not position your desk or seating with its back to the window. Position furniture to maximise your exposure to daylight during the day (when you are most active).
Use light-coloured surfaces. Pale walls, light-coloured flooring, and bright surfaces reflect natural light further into the room. A room with white/cream walls appears significantly brighter than the same room with dark walls and the same amount of natural light entering from windows.
Place mirrors strategically. Mirrors positioned opposite windows will bounce light further into the room. Simple but effective. One large mirror can add 10-15% to the perceived daylight in an interior room.
White ceiling paint. Ceiling surfaces absorb or reflect light. Light-coloured ceiling surfaces (white) will reflect light rather than absorb it. No complicated thinking required – simply ensure your ceilings bounce light around rather than absorb it.
Interior Rooms with No Windows
Options for interior rooms with no windows are limited:
- Light Tubes (Reflective Skylights): £200-500. Tube sunlight from roof to interior room using reflective surfaces. Surprisingly effective.
- Skylights: Structural changes possible. Major investment but will greatly improve.
- Create a Window to Adjoining Room: Create a window to a naturally lit room, if possible. Light will penetrate further.
Why Circadian Rhythm Matters
Humans have a 24-hour biological cycle that is controlled by light. Morning sunlight signals to your body that it is time to wake. Evening darkness signals to your body that it is time to sleep. This is basic human biology.
Morning Light: Exposure to morning sunlight advances your body’s circadian rhythm and improves alertness, mood and sleep quality at night. People generally feel better and sleep better when exposed to morning sunlight.
If you are working in an interior office or your bedroom does not receive morning light, you are working against your body’s natural rhythm.
Blue Light in the Evening: Artificial light, particularly computer screens and overhead lighting, emit wavelengths of light that suppress melatonin (sleep hormone) production. Melatonin is typically produced by the body in response to darkness in the evening. This is why people often sleep poorly after working late under bright overhead lighting.
Application of these concepts:
- Try to place your desk where morning/midday natural light enters.
- Switch to warm light sources (3000K colour temperature or lower) in the late afternoon/early evening, if possible.
- Avoid bright overhead lighting in the 2-3 hours leading up to bedtime.
- Spend time outside or near windows in the morning.
Artificial Light: When You Need It (And How To Do It Correctly)
Many spaces require supplemental artificial lighting. The objective is not to replace natural light, but to fill in the gaps in a manner that supports the circadian rhythms of the occupants.
| Lighting Type | Colour Temperature | Best Use | Disadvantages |
|---|---|---|---|
| Cool White (5000K+) | Bright, blue-tinted | Task-based applications, offices, mornings | Suppresses melatonin production in the evening, can feel sterile |
| Neutral White (4000K) | Balanced | General spaces, all purposes | Satisfies neither the requirements for detail-based task lighting nor the requirements for cosy ambiance |
| Warm White (3000K or lower) | Orange/amber-toned | Evenings, bedrooms, living areas | Less desirable for fine-task-based work, but supportive of sleep |
| Dynamic/Tunable LEDs | Changes from cool (mornings) to warm (evenings) | Supports circadian rhythm | More expensive (£50-£200+ per fixture), but becoming more common |
Key insight: Avoid using bright white/cool light (5000K+) in the evening. It suppresses melatonin and makes it difficult to fall asleep. Warm light (3000K) in the evening is preferred.
Office-based studies have demonstrated that dynamic lighting systems that change from cool (morning alertness) to warm (afternoon focus) enhance both productivity and wellbeing. As the technology continues to become more affordable and widely available, the research is becoming increasingly relevant.
Creating a Lighting Plan for Each Space
Bedrooms: Optimise the natural morning light and use black-out curtains or shades for sleep. Use warm (2700K or lower) evening lighting.
Home Offices: Position your desk to capture natural light. For interior spaces, use warm white task lighting (3000K) to supplement and ensure the overall brightness level is sufficient for concentrated work. Use desk lamps whenever feasible instead of overhead lighting.
Living Areas: Layer your lighting – natural light during the day and soft ambient light in the evening. Do not rely entirely on overhead lighting. Use floor lamps and table lamps with warm-toned bulbs for cosy atmosphere.
Kitchen: Use brighter light levels in kitchen spaces (task-based); natural light if possible, and cool white task lighting over work surfaces.
Bathroom: Similar to kitchen – task-based. Use natural light and cool white supplemental lighting for tasks, but avoid bright light immediately after waking.
Common Light Errors
Dependence on overhead lighting. Single overhead fixtures produce harsh shadows and fatigue. Layer lighting: natural light during the day, softer ambient lighting in the evening, and task-specific lighting where necessary.
Failure to Consider Colour Temperature. Widespread use of 5000K (cool white) lighting throughout the home makes it feel cold and institutional. Change the colour temperature of your lighting by room and by time of day.
Failure to Filter Natural Light for Privacy. Use sheers or cellular shades that filter natural light while allowing for privacy, instead of heavy black-out curtains during the day.
Omitting Consideration of Circadian Rhythm. Working in bright light all day and attempting to sleep in bright light creates a conflicting relationship with your body’s natural cycle. Adjust your lighting as the day progresses.
Failure to Consider Light Distribution. All light from a single location creates unevenness. Place multiple light sources throughout the space to distribute the light evenly.
Integration of Natural Light and Biophilic Design
Natural light supports air quality, thermal comfort, and contributes to occupant wellbeing as a component of a holistic biophilic approach. It is the core element that enables all of the other aspects of biophilic design to operate effectively.
Where to Begin
Honest evaluation of your current light situation: Where does the natural light really enter? Which rooms are bright? Which rooms are dark? Which times of day are the darkest?
Then Prioritise:
- Maximise the existing natural light (clean windows, remove obstructions, rearrange furniture)
- Fill in the gaps where needed (install light tubes for dark rooms, mirrors to reflect light)
- Layer the artificial lighting (warm tone in the evening, task lighting when needed)
- Coordinate with your circadian rhythm (bright in the morning, warm in the evening)
Good lighting does not necessarily require a renovation or significant expenditure. Often, it comes down to working within the limitations of your space and making intentional decisions about supplemental lighting.
Light is the basis for every space being alive. Once you establish a solid foundation of light, everything else you do with biophilic design becomes more impactful.
Sarah is an interior designer who specializes in biophilic design (the connection of humans and nature) and small-space living for urban apartment dwellers. Since working as an interior designer for 12 years, she has redesigned hundreds of flats in London, Manchester and Bristol. As such, Sarah is experienced in creating biophilically connected spaces in areas of homes that appear to be nearly impossible to redesign.
Sarah offers practical interior design solutions for both renter and homeowner, both with very real constraints: limited budget, inability to make structural changes, and every square inch of the home counts. Sarah’s methodology takes the principles of biophilic design and applies them to the realities of living in an urban environment. She has helped numerous clients create biophilic elements in compact, climate-controlled environments – humidity control in loft conversions, increasing daylight in basement conversions, adding biophilic elements in studio apartments that have no wall space.
The basis of Sarah’s philosophy is that biophilic design should not cost a fortune nor require a renovation. Rather, through a series of intelligent decisions, small choices can add up to large results. Sarah writes for people looking to transform their space in a way that does not require landlord approval, nor does it need to be expensive. Her guidebooks are focused on what actually works within the confines of typical UK flat designs, what investments will pay off, and what can be skipped altogether.
