5.4 Daylight Design Strategies (L05), Daylight Simulation (L06) & Occupant Lighting Control (L09)
Key Takeaways
- L05 Part 1 awards 1 point where 70% of workstations are within 25 ft (7.5 m) of transparent glazing with visible light transmittance above 40%, or glazing is at least 15% of regularly occupied floor area, and 2 points at 16 ft (5 m) or 25% glazing.
- L05 Part 2 awards 1 point for manual shading controllable by occupants at all times and opened once daily, or 2 points for shading automated to prevent glare.
- L06 Daylight Simulation awards 1 point for average sDA300,50% across more than 55% of regularly occupied floor area and 2 points for more than 75%.
- L09 Part 1 Option 1 awards 1 point for one lighting zone per 650 ft2 (60 m2) or per 10 occupants, and 2 points for one per 320 ft2 (30 m2) or per 5 occupants.
- L09 Part 2 supplemental lighting must raise task surface light to at least twice the L02 reference level and sit at least 9 in (23 cm) from the front edge of the work surface, or be provided on request at no cost within eight weeks.
5.4 Daylight Design Strategies (L05), Daylight Simulation (L06) & Occupant Lighting Control (L09)
Core Exam Takeaway: L05 Daylight Design Strategies (4 pt / Core 6 pt) — the biggest single optimization in the Light concept — has Part 1 Implement Daylight Plan (2 pt) and Part 2 Integrate Solar Shading (2 pt). L06 Daylight Simulation (2 pt / Core 3 pt) pays for sDA₃₀₀,₅₀% at > 55% (1 pt) or > 75% (2 pt) of floor area. L09 Occupant Lighting Control (3 pt / Core 1.5 pt) pays for zone granularity and supplemental lighting. All three matter beyond their own points, because L05 Part 1 or L06 Part 1 unlocks L03's reduced circadian thresholds.
Feature L05: Daylight Design Strategies — Optimization (4 pt / WELL Core 6 pt)
Intent: provide daylight exposure indoors through design strategies, so daylight may be used for visual tasks alongside electric lighting, and provide a connection to outdoor spaces through windows.
L05 Part 1 — Implement Daylight Plan (2 pt / Core 3 pt)
For all spaces except dwelling units. Meet one row, via either column:
| Interior Layout | OR — Façade Design | Points (Core) |
|---|---|---|
| 70% of all workstations within 25 ft (7.5 m) of transparent envelope glazing, with VLT > 40% | Envelope glazing no less than 15% of the regularly occupied floor area or individual unit, with window VLT > 40% | 1 (2) |
| 70% of all workstations within 16 ft (5 m) of transparent envelope glazing, with VLT > 40% | Envelope glazing no less than 25% of the regularly occupied floor area or individual unit, with window VLT > 40% | 2 (3) |
For dwelling units, by vertical envelope glazing ratio: ≥ 15% of each dwelling unit with VLT > 40% earns 1 point; ≥ 25% with VLT > 40% earns 2 points.
L05 Part 2 — Integrate Solar Shading (2 pt / Core 3 pt)
In regularly occupied spaces, all vertical transparent envelope glazing has shading meeting one of:
| Type of shading | Points (Core) |
|---|---|
| Manual shading controllable by occupants at all times, with shades regularly opened once a day for all days the project is in use | 1 (2) |
| Shading automated to prevent glare | 2 (3) |
WELL Core guidance: whole building. For Part 2, projects may either install shading in tenant spaces or provide a budget to tenants tied to implementation of the feature requirements.
[!IMPORTANT] Visible light transmittance above 40% is a condition on every L05 Part 1 row. A project can hit 25% glazing ratio and still fail if the glass is a VLT-28% high-performance unit. This is the trade-off WELL forces designers to confront: solar-control glazing that protects the cooling load can starve the interior of daylight and circadian stimulus.
[!TIP] Part 2's manual option has a behavioural condition — shades must be opened once a day, every day the project is in use. Manual shades in practice get closed once and left closed for months, which converts a daylit building into a permanently dark one. That is precisely why automated glare-responsive shading earns double.
Feature L06: Daylight Simulation — Optimization (2 pt / WELL Core 3 pt)
Intent: ensure indoor daylight exposure through daylight simulation, so teams make informed fenestration and shading decisions.
L06 Part 1 — Conduct Daylight Simulation
For all spaces except dwelling units. Demonstrate by computer simulation:
| Calculations per IES LM-83-12 | OR — Calculations per Annex A of CEN 17037:2018 | Points (Core) |
|---|---|---|
| Average sDA₃₀₀,₅₀% achieved for > 55% of regularly occupied floor area | Target illuminance 28 fc (300 lux) for > 50% of individual unit area throughout 50% of daylit hours of the year | 1 (2) |
| Average sDA₃₀₀,₅₀% achieved for > 75% of regularly occupied floor area | 28 fc (300 lux) for > 50% of individual unit area, and average 9 fc (100 lux) for > 95% of individual unit area, throughout 50% of daylit hours | 2 (3) |
For dwelling units, the same > 55% / > 75% sDA₃₀₀,₅₀% tiers apply per unit.
WELL Core guidance: whole building. Where finishes are not finalized, use default reflectances: ceilings 80%, walls 50%, floors 20%. The entire floorplate except circulation areas in non-leased spaces is considered regularly occupied.
[!TIP] L05 versus L06 is prescriptive versus performance. L05 pays for measurable geometry — distance to glazing, glazing ratio, VLT, shading type — with no simulation needed. L06 pays for simulated annual outcome, which credits good orientation, light shelves, interior reflectances and shading logic that geometry alone cannot capture. A project may pursue both, and either one's Part 1 unlocks the reduced L03 circadian thresholds.
[!IMPORTANT] Compare the sDA targets across the Light concept and the escalation is obvious: L01 Option 1 asks for sDA₂₀₀,₄₀% over 30% of area (a precondition-level floor); L06 asks for sDA₃₀₀,₅₀% over 55% then 75%. Higher illuminance target, longer time fraction, larger area share.
Feature L09: Occupant Lighting Control — Optimization (3 pt / WELL Core 1.5 pt)
Intent: provide individuals with access to customizable lighting environments.
L09 Part 1 — Enhance Occupant Controllability (2 pt / Core 1 pt)
Option 1: Lighting zones. Ambient lighting systems provide zones per this table. Individual rooms smaller than the listed areas, and/or with occupancies below those listed, are considered separate zones.
| Number of zones | OR | Number of zones | Points (Core) |
|---|---|---|---|
| One per 650 ft² (60 m²) | OR | One per 10 occupants | 1 (0.5) |
| One per 320 ft² (30 m²) | OR | One per 5 occupants | 2 (1) |
Option 2: Lighting control system. Each lighting zone meets:
- (a) Lighting systems have at least three lighting levels or scenes allowing changes in light levels, and the ability to change at least one of: colour, colour temperature, or distribution of light by controlling different groups of lights or through preset scenes.
- (b) All regular occupants have control over their immediate lighting environment through at least one of: manual controls located in the same space as each lighting zone, or a digital interface available on a computer or phone.
- (c) Lighting for presentation or projection walls is separately controlled.
L09 Part 2 — Provide Supplemental Lighting (1 pt / Core 0.5 pt)
For all spaces except dwelling units.
Option 1: Supplemental lighting requirements.
- (a) Occupants are provided supplemental lighting that increases the light level on the task surface to at least twice the recommended light levels based on the reference used to meet L02 Part 1.
- (b) The fixture is positioned to create minimal visual discomfort for the occupant, or per manufacturer installation recommendations.
- (c) The fixture is installed at least 9 in (23 cm) from the front edge of the workstation or other work surface (horizontal distance), or per manufacturer's instructions.
Option 2: Supplemental lighting availability.
- (a) Supplemental light fixtures are provided to occupants upon request at no cost, with requests fulfilled within eight weeks.
- (b) At least one supplemental light fixture is available to occupants for trial purposes.
WELL Core guidance for both parts: non-leased spaces; an additional point for also meeting requirements in leased spaces.
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| L09 PART 1 OPTION 1: ZONE GRANULARITY, TWO WAYS TO COUNT |
| |
| A 6,500 sq ft open office with 40 occupants: |
| |
| 1 POINT tier: 6,500 / 650 = 10 zones OR 40 / 10 = 4 zones |
| 2 POINT tier: 6,500 / 320 = 21 zones OR 40 / 5 = 8 zones |
| |
| The area test and the headcount test are ALTERNATIVES -- take whichever |
| the project can meet. In sparsely occupied space the headcount test is |
| far cheaper; in densely occupied space the area test is. |
| |
| And any individual room smaller than the area threshold, or with fewer |
| occupants than the headcount threshold, counts as its own zone anyway. |
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[!TIP] L09's twice-L02 rule is elegantly relative. Rather than naming an absolute task illuminance, Part 2 Option 1(a) requires supplemental lighting to reach double whatever L02 reference the project used. If the project took L02 Option 2, offices need 30 fc (320 lux) ambient, so a task light must deliver 60 fc (640 lux) at the surface. Ageing eyes, fine detail work and personal preference are all served by the same relative rule.
[!TIP] Option 2 is the low-capital path: stock a few task lights, fulfil requests within eight weeks at no cost, and keep one available to try. That earns the same point as fitting every desk. Note how similar this pattern is to T04 Individual Thermal Control's personal comfort devices "available upon request" — WELL repeatedly accepts access on demand in place of universal provision.
How the daylight and control features feed L03
Both L05 Part 1 and L06 Part 1 are recognized triggers for L03's enhanced daylight thresholds, lowering the electric-light requirement from 150 to 120 EML (1 pt) and from 240 to 180 EML (3 pt). A project that invests in glazing ratio and VLT under L05, or proves annual daylight performance under L06, therefore earns points three times over: the daylight feature itself, a cheaper circadian lighting installation under L03, and — because higher wall reflectances and vertical illuminance help both — an easier path through L07 Visual Balance.
A project places 70% of its workstations within 16 ft (5 m) of transparent envelope glazing with a visible light transmittance of 45%. How many points does L05 Part 1 award for WELL Certification?
Under L05 Part 2, what distinguishes the 1-point and 2-point shading tiers?
What spatial daylight autonomy performance earns the maximum 2 points under L06 Part 1 for a non-residential project?
A project's open office covers 6,400 ft² and houses 32 regular occupants. Which configuration earns the maximum 2 points under L09 Part 1 Option 1?