WELL Lighting Concept
Concept / Light / Intent
The WELL Light concept promotes appropriate human exposure to light, with the objective of creating lighting environments that support visual, psychological, and physiological health.
Concept / Light / Background
Light is the main driver of the visual and circadian systems. Light enters the human body through the eye, where it is sensed by photoreceptors in the retina that are linked to the visual and circadian systems. Humans are diurnal, meaning they are innately prone to wakefulness during the day and sleepiness at night. Light exposure stimulates the circadian system, which starts in the brain and regulates physiological rhythms throughout the body’s tissues and organs, such as hormone levels and the sleep-wake cycle. Disruption or desynchronization of the circadian rhythm has been linked with obesity, diabetes, depression and metabolic disorders. Exposure to bright light at night is associated with circadian phase disruption, which in turn can cause negative health effects, such as breast cancer and metabolic and sleep disorders.
All light—not just sunlight—can influence circadian rhythms. Considering that people spend most of their time indoors, insufficient or inappropriate lighting may cause circadian phase shifts. Research shows that light has positive effects on mood and can alleviate depressive symptoms. Adequate daylight exposure is associated with faster recovery, better cognitive function, and improved work performance.
Feature L01: Light Exposure (Prerequisite)
Summary
This feature requires projects to provide appropriate illumination in interior environments through thoughtful daylighting and electric lighting strategies.
Issue
Humans rely on circadian rhythms, and light is their primary driver. Modern reliance on artificial lighting often reduces daylight exposure, which may lead to depression and impaired cognitive function.
Approach
Adequate light levels should be provided through architectural design, façade design, spatial planning, and lighting design. When daylight is insufficient, electric lighting strategies should be used to achieve the required illumination levels.
Verification Methods
Applicable to all spaces (except dwelling units and guest rooms)
Option 1: Daylight Simulation (Technical documentation)
The project demonstrates, through computer simulations, that one of the following conditions are achieved:
a. The total floor area of regularly occupied spaces achieves one of the following targets:
b. Common space that has unassigned seating for at least 15% of regular occupants at any given time achieves one of the following targets:
Option 2: Interior Layout (Technical Documentation)
The project must meet one of the following requirements:
a. At least 30% of regularly occupied spaces are within a horizontal distance of 6 meters (20 feet) from the building envelope glazing.
b. Common spaces have unassigned seating and can accommodate at least 15% of regular occupants at any given time. At least 70% of all seating in these spaces must be within a horizontal distance of 5 meters (16 feet) from the building envelope glazing.
Option 3: Building Design (Technical Documentation)
The project must meet one of the following requirements:
a. The envelope glazing area is no less than 7% of the regularly occupied floor area.
b. The floor length between opposing walls with envelope glazing does not exceed 20 meters (65 feet), and there are no opaque elements higher than 1.25 meters (4 feet) within a 6-meter (20-foot) horizontal distance from the envelope glazing.
Option 4: Circadian Lighting Design (Performance Testing)
The project should meet the following requirement:
The project complies with Feature L03, Tier 1: Circadian Lighting Design Thresholds.
Applicable to Dwelling Units and Guest Rooms
Option 1: Daylight Simulation (Technical Documentation)
The project demonstrates through computer simulation that The total floor area of regularly occupied spaces of each dwelling unit achieves one of the following targets:
Option 2: Façade Design (Technical Documentation)
The project should meet the following requirement: For each residential unit, the area of building envelope glazing must be no less than 7% of the regularly occupied floor area.
Option 3: Circadian Lighting Design (Performance Testing)
The project should meet the following requirement: The project achieves at least 1 point in Feature L03: Circadian Lighting Design.
Feature L02: Visual Lighting Design (Prerequisite)
Summary
This feature requires projects to provide illuminance levels suitable for work surfaces for users of all ages, considering the lighting levels necessary to perform tasks.
Issue
As people age, their eyes require more light. Inadequate lighting can affect visual performance and comfort.
Approach
Refer to recommendations from lighting associations or authoritative organizations to develop lighting strategies appropriate for different ages and tasks.
Verification Methods
Applicable to all spaces (except Dwelling units)
Option 1: Visual Lighting Design (Technical Documentation + Performance Testing)
a. All indoor and outdoor spaces (including transition areas) comply with the illuminance thresholds specified in one of the following lighting reference guidelines:
- IES Lighting Application Standards
- EN 12464-1:2021 or EN 12464-2:2014
- ISO 8995-1:2002(E) (CIE S 008/E:2001)
- GB50034-2013
- CIBSE SLL Lighting Guides
b. Illuminance levels should consider the task being performed and the age group of users.
Option 2: Preset Illuminance Levels (Technical Documentation + Performance Testing)
Projects should meet the following requirements:
a. More than 50% of the occupants are under the age of 65.
b. The area of outdoor space within the project boundary is less than 5% of the interior project area.
c. At least 90% of the interior project area is comprised of the following space types and meets the associated illuminance thresholds:
Applicable to Dwelling Units
Provide Visual Acuity (Technical Documentation + Performance Testing)
Projects should meet the following requirements:
a. Lighting is installed in kitchens and bathrooms to comply with the illuminance thresholds specified in one of the following lighting reference guidelines:
- IES Lighting Application Standards
- ISO 8995-1:2002(E) (CIE S 008/E:2001)
- GB50034-2013
- CIBSE SLL Lighting Guides
b. For spaces where lighting is not installed, the following is provided to all tenants:
1. Illuminance thresholds for common tasks conducted in spaces
2. Fixture specifications, quantity, and placement needed to achieve the required illuminance based on a typical layout.
Note:
- For projects seeking Bronze or Silver certification, performance testing is not required within residential units.
- For projects seeking Gold or Platinum certification, performance testing must be conducted within residential units.
- For details, refer to the “Sampling Rates for Multi-Unit Residential” section of the WELL Performance Verification Guide.
- Information on sensors/testing requirements, test duration, and compliance calculations can be found in the WELL Performance Verification Guide.
Feature L03: Circadian Lighting Design (Optimized Conditions, up to 3 Points)
Summary
This feature requires projects to provide appropriate lighting to support circadian rhythm health and align with the natural day-night cycle.
Issue
Indoor lighting is often insufficient to support the circadian system, which can lead to rhythm disruption and sleep problems.
Approach
Consider spectrum, brightness, duration, and exposure time to ensure appropriate illuminance on vertical surfaces at occupants’ eye level.
- During daytime, achieve Equivalent Melanopic Lux (EML) ≥ 275 lux.
- At night, reduce EML to minimize suppression of melatonin.
Verification Methods
Applicable to all spaces (Except Dwelling units and Guest rooms)
Performance Testing:
For workstations used during the day, artificial lighting should meet the following threshold:
a. In regularly occupied spaces, at a height of 18 inches above the work plane at all workstations, maintain the required illuminance level for at least four hours (starting no later than noon).
b. Achieve illuminance on vertical surfaces at eye level to simulate the light entering the user’s eyes.
Applicable to Dwelling units and Guest rooms
Performance Testing:
Each residential unit must meet the following requirements:
a. Use artificial lighting to achieve the specified illuminance levels:
Achieve illuminance on vertical surfaces at eye level to simulate the light entering the user’s eyes.
b. Illuminance levels should be adjustable. If automatic lighting is used, it should dim automatically after 8:00 PM.
c. In living rooms and kitchens, illuminance should be measured at a height of 140 cm (55 inches) above the floor at the center of the room. For studio apartments or hotel rooms without a living area, testing can be performed at the center of the room. If a workstation exists, illuminance should be measured at a height of 45 cm (18 inches) above the work plane.
Design Guidance:
It is recommended to refer to WELL standards for specific design principles and parameters.
L04: Electric Light Glare Control (Optimized Feature, up to 2 points)
Summary
This feature requires projects to minimize glare from artificial lighting through design strategies and appropriate luminaires.
Issue
Glare can cause visual discomfort, eye strain, headaches, and even accidents.
Approach
Select appropriate luminaires and lighting layouts to control brightness and contrast.
Verification Methods
Applicable to all spaces (except industrial spaces)
Option 1: Luminaire Considerations (Technical Documentation)
All luminaires within regularly occupied spaces (excluding wall wash fixtures, concealed fixtures, emergency lighting and decorative fixtures installed as specified by the manufacturer) meet one of the following requirements when measured at light output representative of regular use conditions:
a. 100% of light is emitted above the horizontal plane.
b. Unified Glare Rating (UGR) ≤ 19.
c. Luminance at any angle between 45°–90° to the horizontal plane ≤ 6,000 cd/m².
Option 2: Space Considerations (Technical Documentation)
All regularly occupied spaces must achieve: Unified Glare Rating (UGR) ≤ 19.
Applicable to industrial spaces
Option 1: Luminaire Considerations (Technical Documentation)
All luminaires within regularly occupied spaces (excluding wall wash fixtures, concealed fixtures, emergency lighting and decorative fixtures installed as specified by the manufacturer) meet one of the following requirements when measured at light output representative of regular use conditions:
a. Comply with the requirements for “all spaces except industrial spaces.”
b. Unified Glare Rating (UGR) ≤ 19.
Option 2: Space Considerations (Technical Documentation)
All regularly occupied spaces must achieve: Unified Glare Rating (UGR) ≤ 19.
L05: Daylight Design Strategies (Optimized Feature, up to 4 points)
Summary
This feature requires projects to provide indoor daylight exposure through architectural design and connect indoor spaces to the outdoors via view windows.
Issue
A lack of daylight exposure can lead to circadian rhythm disruption and mental health issues.
Approach
Consider natural daylighting at all stages of architectural planning and integrate shading devices to control glare.
Verification Methods
Part 1: Implement Daylight Plan (up to 2 points)
Technical documentation (architectural drawings and window specifications).
Part 2: Integrate Solar Shading (up to 2 points)
On-site photographs + management policies/operations schedules.
L06: Daylight Simulation (Optimized Feature, up to 2 points)
Summary
This feature requires projects to perform daylight simulations to optimize window and shading device designs.
Issue
Architectural design has a significant impact on daylight access, which affects mood, circadian rhythms, and work performance.
Approach
Optimize indoor daylight exposure and shading strategies through daylight simulation.
Verification Methods
Part 1: Conduct Daylight Simulation (up to 2 points)
Technical documentation (simulation report).
L07: Visual Balance (Optimized Feature, up to 1 point)
Summary
This feature requires projects to develop and implement strategies to create a visually comfortable lighting environment.
Issue
Lighting variations can cause visual discomfort and eye fatigue.
Approach
Plan lighting layout and operation schedules, considering color temperature, uniformity, and control of changes.
Verification Methods
Option 1: Parameters for visual balance (Professional Documentation)
Ambient lighting in all regularly occupied spaces meets at least three of the following requirements:
a. The horizontal and vertical brightness contrast between adjacent independently controlled zones does not exceed 10.
b. On any horizontal task surface, the illuminance uniformity ratio is at least 0.4 or 1:2.5 (minimum illuminance : average illuminance).
c. At least one of the following is satisfied:
1. An automatic lighting control system is used, and automatic changes in lighting characteristics (e.g., illuminance level, color, and distribution) occur over at least 10 minutes.
2. No automatic control system is used.
d. The correlated color temperature (CCT) of similar fixtures in each room is consistent at any point in time (±200 K).
Option 2: Design for visual balance (Professional Documentation)
Lighting is designed by a lighting professional, considering the following:
a. Brightness ratios of adjacent vertical and horizontal zones
b. Illuminance uniformity on horizontal task surfaces
c. Changes in lighting characteristics, such as illuminance, color, and distribution
d. Color temperature of the fixtures used
L08: Electrical Lighting Quality (Optimized Feature, up to 3 points)
Summary
This feature requires projects to consider the color rendering and flicker of lighting fixtures to enhance visual comfort.
Issue
Low color rendering and flicker can affect color recognition, cause eye fatigue, and induce headaches.
Approach
Use high color-rendering lighting fixtures and control flicker.
Verification Methods
Part 1: Enhance Color Rendering Quality (1 point)
Documentation: Product specifications
All lighting fixtures in occupiable spaces (excluding decorative lighting, emergency lighting, and other signaling devices) must meet at least one of the following color rendering requirements. For tunable white lighting, the requirements must be met across the range from low (minimum 2,700 K) to high (maximum 5,000 K) in 1,000 K increments:
a. Color Rendering Index (Ra) ≥ 90
b. Color Rendering Index (Ra) ≥ 80, and R9 ≥ 50
c. IES TM-30 P1 (Rf ≥ 78, Rg ≥ 95, -1% ≤ Rcs,h1 ≤ 15%)
Part 2: Manage Flicker (2 points)
Documentation: Product specifications
All lighting fixtures in occupiable spaces, along with appropriate controls (excluding decorative lighting, emergency lighting, and other signaling devices), must meet at least one of the following flicker requirements under normal use:
a. Tested according to JA-10 Appendix and classified under California Title 24 mandatory building energy standards as “reduced flicker operation.”
b. Recommended measures 1, 2, or 3 as defined by IEEE Standard 1789-2015 for LEDs.
c. For indoor applications: Pst LM ≤ 1.0 and SVM ≤ 0.6
L09: User Control of Lighting Environment (Optimized Feature, up to 3 points)
Summary
This feature requires projects to implement innovative lighting strategies that allow users to customize their lighting environment.
Issue
Lighting environments affect health and work performance; giving users control can improve satisfaction.
Approach
Provide a lighting system with zoned control and supplementary lighting devices.
Note: Projects may designate specific spaces within the project where lighting control is limited to certain permanent occupants (e.g., equipment staff, office managers), but these specific spaces must not exceed 10% of the total project area.
Verification Methods
Part 1: Enhance Occupant Controllability (up to 2 points)
Documentation: Lighting zones (technical files) + professional statement (control system)
1. Lighting Zones:
The ambient lighting system shall meet the following requirements: all regularly used spaces must include the lighting zones listed in the table below.
(Note: Independent rooms smaller than the area listed below and/or with a usage rate below the threshold in the table are considered separate zones.)
2. Lighting Control System:
Each lighting control zone must meet the following requirements:
a. The lighting system must have at least three illuminance levels or include scenes that account for changes in light levels, with the ability to adjust at least one of the following:
- Color
- Color temperature
- Distribution of light through control of different lighting groups or via preset scenes
b. All building occupants must be able to control their direct lighting environment by at least one of the following methods:
- Manual controls located within the same space as each lighting zone (e.g., switches or control panels)
- Digital interfaces accessible via computer or phone
c. Lighting of display walls or projection walls can be controlled independently
Part 2: Provide Supplemental Lighting (1 point)
Management Policy + Technical Documentation (Product Specifications)
1. Supplemental lighting availability
- Supplemental lighting fixtures (e.g., task surface lighting) must be provided free of charge to all employees and made available within 8 weeks.
- At least one supplemental lighting fixture must be available for trial use.
2. Supplemental lighting requirements
- Supplemental lighting devices must allow user-adjustable illuminance and operate independently of the ambient lighting system.
- Fixture location can be adjusted by workstation occupants.
- Light-emitting elements must not be visible to users during intended use.
Note: The full range of In. Licht products supports WELL project design, verification, and operational maintenance.
💡 How to Obtain the Most Accurate Information
To ensure that the standards used in your project are absolutely accurate, it is recommended that you:
- Consult official resources directly
The most reliable way is to visit the official platform v2.wellcertified.com. In the “Light” concept section, you can find the most authoritative and detailed descriptions for each clause (L01–L09), including specific parameters and the latest revisions. - Refer to the WELL Performance Verification Guide
This document clearly defines the methods for performance verification during the certification process and serves as a key reference for meeting standards and conducting on-site testing. - Consult professionals
If your project plans to formally apply for WELL certification, it is recommended to work with a WELL AP (WELL Accredited Professional) or an IWBI-approved consulting organization. They can provide expert guidance aligned with the latest standards.
We hope this information provides a clear framework for your project. Always use the official website https://v2.wellcertified.com as the final reference.
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