Daylighting fenestration
- 53 Visual lighting design
- 54 Circadian lighting design
- 55 Electric light glare control
- 56 Solar glare control
- 57 Low-glare workstation design
- 58 Color quality
- 59 Surface design
- 60 Automated shading and dimming controls
- 61 Right to light
- 62 Daylight modeling
- 63 Daylighting fenestration
- P2 Light at night
- P3 Circadian emulation
63. Daylighting fenestration
Exposure to natural light can improve occupant mood, alertness and overall health. Ideal lighting involves proper exposure to diffuse daylight, as well as careful design of windows and glazing to avoid excessive glare and heat gain. Windows are therefore a key variable for both ensuring that occupants receive enough light for positive physiological and subjective effects, but also not too much light that causes discomfort or becomes a source of distraction. Balancing energy performance, thermal comfort and access to quality daylight are essential to proper building design.
This feature outlines design parameters for windows to optimize the quantity and quality of daylight while minimizing unwanted glare and thermal heat gain.
Part 1: Window Sizes for Working and Learning Spaces
The following conditions are met:
a. Window-wall ratio as measured on external elevations is between 20% and 60%. Percentages greater than 40% require external shading or adjustable opacity glazing to control unwanted heat gain and glare.
b. Between 40% and 60% of window area is at least 2.1 m [7 ft] above the floor (Daylight Glass).
Part 2: Window Transmittance in Working and Learning Areas
The following visible transmittance (VT) conditions are met for all non-decorative glazing:
a. All glazing located higher than 2.1 m [7 ft] from the floor (Daylight Glass) has VT of 60% or more.
b. All glazing located 2.1 m [7 ft] or lower from the floor (Vision Glass) has VT of 50% or more.
Part 3: Uniform Color Transmittance
All windows used for daylighting meet the following requirement:
a. The visible light transmittance of wavelengths between 400 and 650 nm does not vary by more than a factor of 2.
Part 4: Window Sizes for Living Spaces
Window/wall ratio as measured on external elevations is:
a. Between 30% and 60% in living rooms.
b. Between 20% and 40% in bedrooms.
Muscular
Nervous
Reproductive
Cardiovascular
Digestive
Endocrine
Immune
Applicability Matrix
| Core & Shell | New & Existing Buildings | New & Existing Interiors | |
|---|---|---|---|
| Part 1: Window Sizes for Working and Learning Spaces | O | O | O |
| Part 2: Window Transmittance in Working and Learning Areas | O | O | O |
| Part 3: Uniform Color Transmittance | O | O | O |
| Part 4: Window Sizes for Living Spaces | - | - | - |
| Commercial Kitchen | Education | Multifamily Residential | Restaurant | Retail | |
|---|---|---|---|---|---|
| Part 1: Window Sizes for Working and Learning Spaces | O | O | - | - | O |
| Part 2: Window Transmittance in Working and Learning Areas | O | O | - | - | O |
| Part 3: Uniform Color Transmittance | O | O | O | - | O |
| Part 4: Window Sizes for Living Spaces | - | - | O | - | - |
Verification Methods Matrix
| Letters of Assurance | Annotated Documents | On-Site Checks | |
|---|---|---|---|
| Part 1: Window Sizes for Working and Learning Spaces | Architectural Drawing | Spot Check | |
| Part 2: Window Transmittance in Working and Learning Areas | Architect | ||
| Part 3: Uniform Color Transmittance | Architect | ||
| Part 4: Window Sizes for Living Spaces | Architect | Architectural Drawing | Spot Check |