Design Development

For Option 1, find out the Visual Light Transmittance (VLT) value of the glazing and enter it on the LEED EQc8.1–8.2

Identify the glazing type within each regularly occupied space. The LEED Reference Guide includes a helpful figure (p. 374) and chart of daylighting design criteria (p. 375) to help determine glazing type. The possible glazing types identified by LEED include the following:

Run prescriptive design calculations to verify that the required percentage of regularly occupied areas meets the required levels for credit compliance. Use the LEED EQc8.1–8.2

Option 1:  Glazing Factor Calculation

Identify the regularly occupied spaces and their square footage.

Glare can hinder the use of a space and be unpleasant for occupants. Daylight modeling can help project teams anticipate problem areas due to sun angles as they interact with the architecture. Exterior and interior shading along with associated controls can greatly reduce the effects of glare.

Integrate glare control into the design.

Daylight controls, sensors, integrated blinds, and lighting controls come with moderate first costs but will bring energy savings over the long run.

Daylight sensors that adjust lamp brightness based on the presence of natural light can greatly reduce lighting energy loads. On average, commercial buildings use 25% of their energy for lighting. Dimming ballasts are more expensive up front and complicated to specify than stepped ballasts.

A common misconception is that a design needs to have more glazing for effective daylighting. Effective daylighting can also be achieved with smaller apertures and glazing designed for specific indirect light, located high in a space to bounce light on to a ceiling bringing light deeper into a space.