8.2 LIGHTING DESIGN - NATURAL LIGHTING & DAYLIGHTING

NATURAL LIGHTING

Light emitted by the sun and reaches the earth's surface.

NATURAL LIGHTING

Sunlight enters a building through openings, and it changes in intensity and quality throughout the day and across different seasons.

Full Spectrum Light

Includes all wavelengths of visible light, which contributes to high color rendering and natural appearance of objects.

Seasonal Variations

Given the proximity to the equator, natural light is abundant in the Philippines, with almost equal day and night lengths throughout the year. Because of the Earth's 23.5° tilt:

23.5°

tilt of the Earth

Summer solstice

ALTITUDE: 26° AZIMUTH: 58°

June 21

Summer solstice date

Winter solstice

ALTITUDE: 73° AZIMUTH: 121°

December 21

Winter solstice date

Summer solstice

Sun takes a higher, longer path.

Summer solstice

Longer daylight hours.

Summer solstice

Sun rises northeast and sets northwest.

Winter solstice

Sun takes a lower, shorter path

Winter solstice

Short daylight hours.

Winter solstice

Sun rises southeast and sets southwest.

March 21 & September 21

Equinoxes date

Equinoxes

Sun rises due east and sets due west

Equinoxes

Equal day and night length.

Sun Path

The apparent movement of the sun across the sky throughout the day and year.

East

Direct sunlight in the morning, cooler later in the day.

East

3500K-4500K

East

Morning - Warm, Noon - Cooler

East

Best location for: living areas, dining areas, play areas

South

Direct sunlight most of the day, especially around noon. Most Consistent Light.

South

Around 4000K-5000K

South

Best location for: garden, utility areas, service areas

West

Direct sunlight in the late afternoon, causing heat gain.

West

3000K-4000K

West & South

Warmer

West

Best location for: kitchen, carport, bathrooms, utility areas, service areas

North

Indirect light throughout the day, more consistent and cooler.

North

Around 6000K or more

North

Cooler

North

Best location for: bedrooms, living areas, balconies, terraces, offices

Energy Efficiency and Sustainability

Daylighting reduces the need for artificial light, lowering utility costs and reduces the building's carbon footprint and reliance on electricity

Human Health and Well-being

Exposure to natural light positively impacts mood, productivity, and well-being. It helps regulate circadian rhythms, improving sleep patterns and overall health.

Aesthetic Appeal

Natural light enhances the appearance of interiors by highlighting textures, colors, and architectural details. It changes dynamically throughout the day, creating a livelier and inviting atmosphere.

Glare

Sunlight can cause glare, making certain areas uncomfortable or difficult to use.

Heat Gain

Too much sunlight, especially in warm climates, can increase indoor temperatures, leading to higher cooling costs.

Urban Heat Island (UHI)

Urban areas experience higher temperatures than surrounding rural areas due to human activities and the built environment. Cities, with their dense buildings, roads, and infrastructure, absorb and retain more heat, leading to localized warming.

Inconsistency & Limited Control

Natural light levels fluctuate throughout the day & year, depending on weather, season, and building orientation. It is also subject to the environment, making it difficult to control.

DAYLIGHTING

The use of light from the sun and sky to complement or replace electric light with appropriate fenestration and lighting controls to modulate daylight admittance.

Sunlight (Direct Component)

Source: Sun (direct beam radiation).

Sunlight (Direct Component)

Characteristics:

• Strong, intense, and directional.

• Creates sharp shadows.

• Can cause glare and overheating if uncontrolled.

Sunlight (Direct Component)

Considerations:

• Best used for accent lighting or highlighting spaces.

• Requires shading devices (louvers, overhangs, blinds).

• Building orientation matters: east/west sunlight is the hardest to manage due to low angles.

Skylight (Diffuse Component)

Source: Sky dome (atmosphere scattering sunlight).

Skylight (Diffuse Component)

Characteristics:

• Soft, diffuse, and evenly distributed.

• Produces gentle shadows or none at all.

• Color shifts with sky conditions (blue sky vs. overcast).

Skylight (Diffuse Component)

Considerations:

• Ideal for general illumination and visual comfort. G

• Works best with clerestories, skylights, and light shelves.

• Provides more consistent daylight factor values, even in cloudy conditions.

Diffused Light

• Soft, uniform light entering from larger, regular openings.

• Best from north/south, reliable and comfortable

Diffused Light

Sources:

• North: consistent diffuse

• South: from reflective surfaces

Windows

are openings fitted with glass to admit light and are often openable to allow ventilation.

window

The higher the _____, the deeper the daylighting zone.

Windows

Effective for daylighting but require low-E/tinted glazing to reduce heat.

1.5-2x

Rule of thumb: daylight zone depth = ______ window head height.

Punched Windows

Small, individual window openings in a wall that create contrasts of light and shade

Punched Windows

breaks can create contrasts of light and dark areas.

Ribbon Windows

Strip Windows

Ribbon Windows

Long, continuous horizontal bands of glazing that uniform daylight.

Ribbon Windows

Type of window that give more uniform daylight.

Clerestory Windows

A large window or series of small windows along the top of a structure's wall, usually at or near the roof line.

Clerestory Windows

Good for effective ceiling illumination (which provides deeper penetration and good distribution) and other glare-sensitive tasks.

Light Shelves

Horizontal reflective surfaces (inside or outside) that bounce daylight onto ceilings for deeper penetration and reduced glare.

Light Shelves

Bounce light deeper into spaces, reducing glare.

Light Shelves

It can be fixed either externally, internally or both.

Light Shelves

Could be installed on north facades, but best on south façades with reflective ceilings. Less effective on east/west due to low angle sun.

600mm

Considerations for Effective Light Shelf Installation:

Minimum distance from the ceiling

height of the glazing above it

Considerations for Effective Light Shelf Installation

the depth of a light shelf =

8% to 11%

Considerations for Effective Light Shelf Installation:

Upper glazing area should be ____ to ____ of the floor area.

3000mm

Considerations for Effective Light Shelf Installation:

Minimum clear height

Direct Light

Sunlight that falls directly on floors, walls, or surfaces without scattering.

Direct Light

Very intense due to tropical latitude and creates sharp shadows, strong contrast, and heat gain.

Direct Light

Generally unwanted for general illumination, but can be used as an accent or dramatic effect.

Direct Light

Uncontrolled from east/west, must be shaded; south easier to manage with overhangs.

Direct Light

Sources:

• Sun: direct beam

• East: direct morning sun, best source of vitamin D

• West: afternoon sun causes glare and overheating, best location for utility spaces due to UV rays exposure

• South: high and consistent exposure

East & West Facades

Fixed or adjustable vertical fins/louvers

East & West Facades

Deep verandas

East & West Facades

Pergolas with deciduous vines

Northeast & Northwest Facades

Adjustable shading

Northeast & Northwest Facades

Pergolas with deciduous vines - to allow heat penetration

Northeast & Northwest Facades

Deep verandas to exclude heat penetration

Southeast & Southwest

Deciduous in cool climates

Southeast & Southwest

Evergreen in hot climates

South

Fixed/adjustable horizontal overhangs

Flexible Shading Fenestrations

Egg-crate, recessed windows

Filtered Daylight

Glass tints, screens, perforated panels, capiz windows

Zenith Light

Light entering from above through roof or ceiling systems.

Zenith Light

Useful but must address heat, glare, and rainproofing.

Zenith Light

Good with atriums, sheds, and lanternins; risky with skylights.

Zenith Light

Sources:

• Vertical entry

• Overhead sky: comes directly from the zenith

Lightwell

A vertical shaft that brings daylight and air to lower floors of a building.

Lightwell

Can double as a courtyard/open space if larger in scale.

Lightwell

Parameters:

• For 2 storeys: Min. width = 2.00m

• For every additional storey: +0.30m width.

• Length depends on site and building design but should allow adequate daylight/ventilation.

Atriums

A large, central open space under a glazed roof that provides daylight to multiple levels

Atriums

These open directly on roofs, in most cases with pyramidal or gabled geometries.

Atriums

This typology is recommended for buildings with a greater number of floors.

Skylights

An opening in the roof fitted with transparent/translucent glazing to admit daylight from above.

Skylights

It allows the direct entrance of natural light into the internal region of the construction.

Skylights

The use of translucent glass on its upper side allows a high percentage of light but also tend to gain thermal loads, which increases temperature.

Skylights

A layer of laminated glass or poly carbonate can be used which allows light to enter indirectly and reduces the light percentage.

Saw-tooth

Shed