Interior Science: Lighting for Wellbeing

Interior Science
Written By Jennifer Baxter

Two Science-Backed Lighting Principles Every Homeowner Should Know

Lighting is both an art and a science, but it's the science that makes all the difference. While most of us focus on fixtures and aesthetics, the real power of lighting lies in how it shapes our physical response to a space. With humans receiving 80-90% of external information through vision, the light in our homes directly affects our mood, cognitive focus, and circadian rhythms.

Studies in neuroaesthetics and environmental psychology show that our perception of light triggers measurable changes in brain activity. The science behind light's impact on perception involves complex interactions between our visual system (rods, cones, and specialized receptors) and emotional processing centers in the frontal cortex. While the full neuroscience is intricate (and I don't profess to understand it!), the practical applications for creating more supportive living spaces are surprisingly straightforward.

Thanks to my studies in Lighting at NYSID and years of experience designing homes that aim to feel as good as they look, I’ve distilled the most critical guidance into two evidence-based principles:

 

Principle 1: Layer Your Lighting with Intention

The most livable rooms use three types of lighting: Ambient, Focused, and Sparkle. Richard Kelly, a pioneer of architectural lighting, anchored his philosophy of light on these three principles, but today it’s also reinforced by neuroscience.

Research shows that soft ambient lighting plays a crucial role in cognitive function and emotion regulation. Further, layered lighting supports sensory modulation: giving people control over sensory input has been shown to reduce stress. Poor lighting, on the other hand, can lead to “perceptual fatigue” when the brain doesn’t have enough depth cues to comfortably navigate a space. Therefore both Ambient and Focal lighting can play an important role in how we feel in a space.

The Sparkle is perhaps less scientific, but who can argue that a bit of sparkle, whatever that looks like for you, doesn’t make one feel better?

HOW TO LAYER:

  • Ambient Lighting: Create a foundation layer that casts an even, illuminating glow across the entire space. This base layer should feel natural. Use ceiling fixtures or sconces that cast a soft, even glow.

  • Focused Lighting: Add task-specific sources like floor lamps, table lamps, directional sconces or overhead pendants positioned where activities actually happen. For reading in bed, ensure the light source sits high enough to illuminate without glare. For a desk or countertop, make sure there is nothing casting a shadow into the workspace. 

  • Sparkle Lighting: Introduce visual interest through decorative pendants, sconces, or candles that act as the "jewelry" of the room.

  • Control Systems: Install dimmers to give yourself greater control over mood and brightness throughout the day.

  • Fixture Strategy: Avoid flush mounts in favor of pendants or semi-flush fixtures to add character and distribute light more evenly, avoiding glare on surfaces. Use sconces and uplights to soften vertical surfaces and reduce harsh contrasts. Use table lamps to bring the light down into the space. Mix fixture styles to create visual variation while maintaining overall harmony.

 

Principle 2: Check Your Numbers

Even the most beautiful fixture fails if the bulb casts the wrong light or the fixture doesn’t provide enough light for the space. Three technical specifications fundamentally determine how we experience a space:

  • Color Rendering Index (CRI):

    • CRI is a measure of how well a light source shows the colors of objects compared to a natural light source.

    • A higher CRI ensures finishes, furnishings, skin tones appear accurately.

    • Particularly critical with artwork or when working with layered neutrals or subtle color undertones, and in the kitchen and dining room, as it impacts our experience of the food we eat.

  •  Color Temperature (Kelvin):

    • Warm light is similar to the color of natural evening light, encouraging melatonin production and promoting relaxation.

    • Cool light can be energizing but often feels sterile in residential settings.

  • Lumens:

    • Lumens are a measure of brightness that is much more indicative of the light in the space than wattage which is how much power is consumed.

    • The target lumens for a room depends on the size of the space and the way the room is used (higher lumens per sq ft for activity areas).

    • You can achieve the total lumens for a room by adding lumens from multiple fixtures: a chandelier, wall sconces, recessed lights and table or floor lamps.

HOW TO CHECK YOUR NUMBERS:

  • Choose Bulbs as Carefully as Fixtures

    • Color Temperature: Use 2700K bulbs for most living spaces. Up to 3000K is ideal for kitchens, bathrooms, or workspaces.

    • Always check CRI - especially if your design relies on color nuance, art, or natural materials - and aim for 90+ CRI.

  • Do The Math:

    • Determine the square footage and the appropriate level of lighting per square foot for the space you are illuminating.

      • For most living areas, 10-20 lumens per square foot is a good target, while kitchens, bathrooms and work areas need more (70-80 lumens per square foot).

    • Calculate your target lumens for the space by multiplying your square footage by the level of lighting per square foot.

    • Check out the product specs for each fixture and add them up to see if you are meeting your target lumens for the square footage of the room.

 

Reframing Light as a Design Material

Lighting is often treated as a technical detail - an afterthought that comes after furniture and finishes. But when we understand its profound influence on mood, clarity, and our connection to place, it's clear that lighting is a foundational material, like paint or flooring.

 

A Final Thought

Before making major changes to a room that feels "off," examine the lighting first. A higher-CRI bulb, a shifted fixture height, or the introduction of a secondary light source can dramatically transform the space visually, emotionally, and functionally. The goal isn't perfect lighting - it's intentional lighting that supports how you actually live to create a home that doesn't just look beautiful but actively supports your wellbeing.

 

Further Reading

Jennifer Baxter
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