# Specify a Skylight

Once a skylight is drawn, we can specify the System U-value (or System R-value), System SHGC, and VLT of the system. When initially drawn, all assume performance values per the Skylights Default specification. This can also be overridden by applying concepts to a skylight.

## Skylight Default Specifications

To update the default specification for a skylight, navigate to the Envelope specification area and select Skylights. Next, under 'Skylight Default', update the desired System U-value (or System R-value), System SHGC, and VLT of the system to preferred values.

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