Log in
LEED v2009
Retail – Commercial Interiors
Indoor Environmental Quality
Daylight and views - daylight

LEED CREDIT

Retail-CI-v2009 IEQc8.1: Daylight and views - daylight 1-2 points

LEEDuser’s viewpoint

Frank advice from LEED experts

LEED is changing all the time, and every project is unique. Even seasoned professionals can miss a critical detail and lose a credit or even a prerequisite at the last minute. Our expert advice guides our LEEDuser Premium members and saves you valuable time.

Credit language

USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To provide occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas1 of the tenant space.

Requirements

Through 1 of the 4 options, achieve daylighting in at least the following spaces2:

Regularly Occupied Spaces

Points

75%

1

90%

2

Option 1. Simulation
Demonstrate through computer simulation that the applicable spaces achieve daylight illuminance levels of a minimum of 10 footcandles (fc) (108 lux) and a maximum of 500 fc (5,400 lux) in a clear sky condition on September 21 at 9 a.m. and 3 p.m. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.
Option 2. Prescriptive
For sidelighting zones:
  • Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area ratio (WFR) between 0.150 and 0.180.
  • 0.150

    VLT

    x

    WFR

    0.180

  • The window area included in the calculation must be at least 30 inches (0.8 meters) above the floor.
  • In section, the ceiling must not obstruct a line that extends from the window-head to a point on the floor that is located twice the height of the window-head from the exterior wall as measured perpendicular to the glass (see diagram on the next page).
  • Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 0.150 value.
For toplighting zones:
  • The toplighting zone under a skylight is the outline of the opening beneath the skylight, plus in each direction the lesser of (see diagram below):
    • 70% of the ceiling height
    • 1/2 the distance to the edge of the nearest skylight
    • The distance to any permanent partition that is closer than 70% of the distance between the top of the partition and the ceiling.
  • Achieve skylight coverage for the applicable space (containing the toplighting zone) between 3% and 6% of the total floor area.
  • The skylight must have a minimum 0.5 VLT.
  • A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTM D1003.
Option 3. Measurement
Demonstrate through records of indoor light measurements that a minimum daylight illumination level of 10 fc (108 lux) and a maximum of 500 fc (5,400 lux) has been achieved in the applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid and shall be recorded on building floor plans. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.
Option 4. Combination
Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces. See all forum discussions about this credit »

What does it cost?

Cost estimates for this credit

On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.

Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.

This information is also available in a full PDF download in The Cost of LEED v4 report.

Learn more about The Cost of LEED v4 »

Documentation toolkit

The motherlode of cheat sheets

LEEDuser’s Documentation Toolkit is loaded with calculators to help assess credit compliance, tracking spreadsheets for materials, sample templates to help guide your narratives and LEED Online submissions, and examples of actual submissions from certified LEED projects for you to check your work against. To get your plaque, start with the right toolkit.

Get the inside scoop

Our editors have written a detailed analysis of nearly every LEED credit, and LEEDuser premium members get full access. We’ll tell you whether the credit is easy to accomplish or better left alone, and we provide insider tips on how to document it successfully.

USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To provide occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas1 of the tenant space.

Requirements

Through 1 of the 4 options, achieve daylighting in at least the following spaces2:

Regularly Occupied Spaces

Points

75%

1

90%

2

Option 1. Simulation
Demonstrate through computer simulation that the applicable spaces achieve daylight illuminance levels of a minimum of 10 footcandles (fc) (108 lux) and a maximum of 500 fc (5,400 lux) in a clear sky condition on September 21 at 9 a.m. and 3 p.m. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.
Option 2. Prescriptive
For sidelighting zones:
  • Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area ratio (WFR) between 0.150 and 0.180.
  • 0.150

    VLT

    x

    WFR

    0.180

  • The window area included in the calculation must be at least 30 inches (0.8 meters) above the floor.
  • In section, the ceiling must not obstruct a line that extends from the window-head to a point on the floor that is located twice the height of the window-head from the exterior wall as measured perpendicular to the glass (see diagram on the next page).
  • Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 0.150 value.
For toplighting zones:
  • The toplighting zone under a skylight is the outline of the opening beneath the skylight, plus in each direction the lesser of (see diagram below):
    • 70% of the ceiling height
    • 1/2 the distance to the edge of the nearest skylight
    • The distance to any permanent partition that is closer than 70% of the distance between the top of the partition and the ceiling.
  • Achieve skylight coverage for the applicable space (containing the toplighting zone) between 3% and 6% of the total floor area.
  • The skylight must have a minimum 0.5 VLT.
  • A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTM D1003.
Option 3. Measurement
Demonstrate through records of indoor light measurements that a minimum daylight illumination level of 10 fc (108 lux) and a maximum of 500 fc (5,400 lux) has been achieved in the applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid and shall be recorded on building floor plans. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.
Option 4. Combination
Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces.
See all LEEDuser forum discussions about this credit » Subscribe to new discussions about Retail-CI-v2009 IEQc8.1