EQ Credit: Daylight (1–3 Points)
👉 “Daylight = 300–3000 lux + glare control”
👉 This credit is about bringing natural light into the building
Benefits:
- Better health (circadian rhythm)
- Higher productivity
- Reduced electric lighting
🎯 Intent
To connect occupants with the outdoors, reinforce circadian rhythms, and reduce electric lighting use
⚠️ CORE REQUIREMENT (VERY TESTABLE)
👉 Glare control devices are REQUIRED
- Must be:
- Manual OR
- Automatic with manual override
🔑 THREE OPTIONS
Option | Method | When Used |
Option 1 | Simulation (Spatial Daylight) | Most common |
Option 2 | Simulation (Illuminance levels) | Simpler calc |
Option 3 | Measurement | Existing buildings |
💻 OPTION 1: SIMULATION (SPATIAL DAYLIGHT)
📊 REQUIREMENTS
Points | Requirement |
2 points | ≥ 55% of floor area |
3 points | ≥ 75% of floor area |
👉 Uses daylight simulation models
💡 OPTION 2: SIMULATION (ILLUMINANCE LEVELS)
📊 REQUIREMENTS
Points | Requirement |
1 point | ≥ 75% area |
2 points | ≥ 90% area |
🔹 KEY CONDITION
- Illuminance must be:
👉 300–3,000 lux - At:
👉 9 AM and 3 PM - On:
👉 Clear day at equinox
📏 OPTION 3: MEASUREMENT
📊 REQUIREMENTS
Points | Requirement |
2 points | ≥ 75% area |
3 points | ≥ 90% area |
🔹 KEY RULES
- Measure:
- Between 9 AM – 3 PM
- At workplane height (30 inches)
- Take 2 measurements
- At least 4–5 months apart
🧠 MEMORY STRUCTURE
👉 3 Options = Simulation, Simulation, Measurement
👉 Key numbers:
- 55 / 75 (Option 1)
- 75 / 90 (Option 2 & 3)
- 300–3000 lux
- 9 AM / 3 PM
🌞 GLARE CONTROL (VERY IMPORTANT)
✅ ACCEPTABLE
- Blinds
- Shades
- Curtains
- Movable louvers
- Movable screens/awnings
❌ NOT ACCEPTABLE
- Fixed overhangs
- Fixed fins/louvers
- Dark glazing
- Fritted glass
⚠️ SPECIAL CASE
👉 No glare control needed for:
- Diffused/translucent glazing
🧠 MEMORY TRICK
👉 “Movable = acceptable, Fixed = NOT acceptable”
💡 DESIGN STRATEGIES (PROJECT + EXAM)
- Building orientation (early design)
- Open floor plans
- Low partitions
- Interior glazing
- Daylight simulations early
⚠️ COMMON EXAM TRAPS
Trap | Reality |
Glare control optional | ❌ Required |
Fixed shading acceptable | ❌ Not allowed |
Any lux value acceptable | ❌ Must be 300–3000 |
Measurement anytime | ❌ 9 AM–3 PM only |
One measurement enough | ❌ Need two |
Options can be combined | ❌ Only one option |
🧠 SUMMARY
👉 Daylight = light + no glare
👉 3 ways to prove it:
- Simulate it
- Calculate it
- Measure it
Requirement | Key Rule |
Glare control | Required for ALL options |
Acceptable devices | Operable only |
Measurement option | 2 measurements |
Lux range | 300–3000 lux |
Option 1 thresholds | 55% / 75% |
Fixed shading | ❌ Not allowed |
Official FAQs
What illuminance range is required?
B. 300–3000 lux
C. 500–5000 lux
D. 1000–10,000 lux
✅ Answer: B
A project uses fixed exterior louvers for glare control. Does it comply?
👉 Fixed exterior louvers are NOT acceptable because:
• They cannot be adjusted by occupants
• They do not respond to changing daylight conditions
________________________________________
📌 Acceptable Devices:
• Interior blinds/shades
• Curtains
• Movable exterior louvers/screens/awnings
❌ Not Acceptable:
• Fixed louvers
• Fixed overhangs
• Tinted/dark glazing
A project measures daylight only once. What is missing?
B. Second measurement
C. Simulation model
D. Glare control
✅ Answer: B
Under Option 3: Measurement:
• Daylight must be measured TWICE
• Measurements must be taken:
o At two different times of the year
o At least 4–5 months apart
👉 This ensures seasonal variation (sun angle changes)
________________________________________
⚠️ Exam Tip
👉 Measurement option = 2 measurements required
A project meets illuminance levels but does not install glare controls. What is the result?
B. Earns partial points
C. Does not comply
D. Needs retesting
✅ Answer: C
Explanation
Glare control is a mandatory requirement for ALL options in the Daylight credit.
👉 Even if:
• Illuminance levels are correct
• Simulation or measurement is perfect
❌ Without glare control → NO compliance
________________________________________
🎯 Why LEED requires this:
• Too much daylight = glare
• Glare reduces:
o Comfort
o Productivity
o Usability of space
________________________________________
⚠️ Exam Trap
👉 Daylight ≠ just light levels
👉 Must include glare control ALWAYS
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