This case study presents a LEED v5 daylight compliance assessment for a typical guestroom floor of a high-rise hotel located in Turin, Italy. The project is a 22-storey high-rise hotel located in Turin, Italy. Each typical floor comprises six guest rooms arranged around a central circulation core, resulting in a typical floor plan of approximately 318 m². The daylight assessment was conducted on a representative Guest room floor, where guest rooms were considered regularly occupied spaces in accordance with LEED v5, while corridors and restrooms were excluded from the compliance calculations.

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Assessment Scope

• Building type: Hospitality

• Assessment standard: LEED v5 BD+C

• Assessment scope: Typical guestroom floor

• Occupied spaces: Guest rooms

• Excluded spaces: Corridor, Restrooms

• Simulation engine: Radiance

• Compliance metric: sDA150,50 & ASE1000,250

LEED v5 Daylight Compliance 

The daylight assessment follows the new version v5 of LEED BD+C – EQ Credit 2: Occupant Experience – Option 5: Lighting Environment. Compared with LEED v4, LEED v5 consolidates Daylight and Interior Lighting into a single credit, separates Solar Glare Control into an independent pathway, and adopts annual climate-based daylight simulation as the only compliance method. Compliance is determined using average sDA, while ASE is used solely to identify spaces requiring glare mitigation. 

Assessment Summary: LEED v5 EQ Credit 2 – Occupant Experience, Option 5 – Lighting Environment

Total Achieved (within the scope of this assessment): ✔ 5/7 points

• Path 1 – Solar Glare Control: ✔ 1 point

• Path 4 – Daylight Simulation: ✔ 4 points

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Façade System

The building adopts a unitized curtain wall Façade system with a typical module size of 3500 × 1500 mm and an overall Window-to-Wall Ratio (WWR) of 46%. The façade system consists of:

• Pacifica – Solarban 70 Krypton insulated glazing.

• Visible Light Transmittance (VLT): 27%.

• Visible Light Reflectance (Exterior / Interior): 5% / 9%.

• U-value: 1.0 W/m²K.

• Solar Heat Gain Coefficient (SHGC): 0.18.

Opaque façade components consist of red aluminium mullions with the following optical properties:

• Total reflectance: 7.66%.

• Specular reflectance: 2.27%.

• Diffuse reflectance: 5.39%.

Interior Material Assumptions

Standard interior reflectance values recommended by IES LM-83 were adopted to minimise the influence of interior finishes on daylight performance and to ensure consistency between projects.  The interior optical properties were defined as follows: 

• Interior wall reflectance: 50% diffuse reflectance.

• Ceiling reflectance: 70% diffuse reflectance.

• Floor reflectance: 20% diffuse reflectance

Simulation Setup 

The daylight assessment was carried out using Climate-Based Daylight Modelling (CBDM) following the methodology defined in IES LM-83, which is the simulation protocol referenced by LEED v5. The annual simulation settings were: 

• Simulation period: 365 days per year.

• Occupied hours: 08:00–18:00, 10 hours per day.

• Total occupied hours: 3,650 hours per year.

• Daylight metrics: Spatial Daylight Autonomy (sDA150,50) and Annual Sunlight Exposure (ASE1000,250).

*LEED v5 no longer permits point-in-time illuminance calculations or field measurements for daylight compliance. 

Spatial Daylight Autonomy (Path 4)

The annual daylight simulation indicates that all guestrooms achieve full daylight autonomy, with sDA150,50 values of 100% across all evaluated spaces. Simulation results indicate:

• Room 1: 100.00%

• Room 2: 100.00%

• Room 3: 100.00%

• Room 4: 100.00%

• Room 5: 100.00%

• Room 6: 100.00%

Conclusion

The project achieved an average sDA150,50 of 100%, significantly exceeding the LEED v5 threshold of 75% required for the maximum Path 4 score. These results demonstrate that the selected façade configuration, including the glazing specification and 46% WWR, provides sufficient daylight availability for all guestrooms while satisfying the highest LEED daylight performance requirement. 

Annual Sunlight Exposure

Annual Sunlight Exposure (ASE1000,250) quantifies the percentage of regularly occupied floor area receiving direct sunlight exceeding 1,000 lux for more than 250 hours per year. Unlike LEED v4, ASE is not used to determine the daylight score in LEED v5. Instead, guestrooms with ASE1000,250 greater than 20% are required to demonstrate appropriate glare mitigation measures.

Simulation results indicate:

• Room 1: 8.57%

• Room 2: 0.00%

• Room 3: 13.05%

• Room 4: 33.56%

• Room 5: 34.82%

• Room 6: 49.33%

Conclusion

Rooms 1–3 satisfy the LEED reference threshold of ASE ≤20%. Rooms 4–6 exceed the LEED reference threshold and therefore require additional glare mitigation measures to improve visual comfort

References

• U.S. Green Building Council (USGBC). (2025). LEED v5 Building Design and Construction (BD+C): EQ Credit 2 – Occupant Experience, Option 5 – Lighting Environment. Washington, DC: U.S. Green Building Council.

• U.S. Green Building Council (USGBC). (2025). LEED v5 BD+C Reference Guide. Washington, DC: U.S. Green Building Council.

• Illuminating Engineering Society (IES). (2023). IES LM-83-23: Approved Method – IES Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE). New York, NY: Illuminating Engineering Society.

• Illuminating Engineering Society (IES). (2020). IES Lighting Handbook, 11th Edition. New York, NY: Illuminating Engineering Society.

• ClimateStudio. (2025). ClimateStudio User Guide and Technical Documentation. Solemma LLC.

• ASHRAE. (2022). ANSI/ASHRAE Standard 55-2020: Thermal Environmental Conditions for Human Occupancy. Atlanta, GA: ASHRAE. (Referenced for occupancy schedule and indoor environmental assessment where applicable.)

Software

Rhinoceros 8, Grasshopper, Ladybug Tools, Climate Studio (Radiance)