# Green Star ## What is Daylight in Green Star? Daylight in Green Star focuses on delivering well-lit spaces that provide high levels of visual comfort to building occupants. Points are awarded when project teams can demonstrate that a specified proportion of a nominated area receives high daylight levels. ## Compliance Using Daylight Factor Daylight Factor can be used as follows: > *"High Levels of daylight are deemed to have daylight factors above 2.0% for all spaces, except living rooms and dining rooms in residential primary spaces, where the threshold is a 1.5% daylight factor."* When calculating the Daylight Factor, Green Star recommends using either a CIE overcast sky or a CIE uniform sky, and the grid is either at the finished floor level or 720mm above FFL. ## Compliance Using Daylight Autonomy Daylight Autonomy can be used as follows: > *"High Levels of daylight are deemed to have at least 160 lux due to daylight during 80% of the nominated hours."* Green Star recommends that simulations must be completed for at least every hour during the Nominated Hours. {% hint style="info" %} The project team must demonstrate that the software used to determine compliance is based on the [Radiance](https://docs.betterbuilding.io/support-and-training/other-support/testing-and-verification/radiance-v-5.2) simulation engine and that it uses the statistical sky, the daylight coefficients, the Perez All-Weather Sky model, or the annual CIE sky simulation algorithms. {% endhint %} ## Modelling Daylight for Green Star in Speckel To meet the requirements of Daylight for Green Star, the Purpose of the [Space](https://docs.betterbuilding.io/user-guide/workflows/daylight/daylight-info/broken-reference) must be defined within the model for that Space to be selected for assessment. In this case, the 'Living Spaces' must be defined with a [Purpose](https://docs.betterbuilding.io/user-guide/workflows/daylight/daylight-info/broken-reference). Once defined, the [Daylight form](https://support-and-docs.gitbook.io/speckel-docs/user-manual/building/simulation/daylight) is used to nominate the [Metric](https://docs.betterbuilding.io/user-guide/workflows/daylight/daylight-info/broken-reference), [Grid](https://docs.betterbuilding.io/user-guide/workflows/daylight/daylight-info/broken-reference), [Surface](https://docs.betterbuilding.io/user-guide/workflows/daylight/daylight-info/broken-reference) and [Simulation Settings](https://docs.betterbuilding.io/user-guide/workflows/daylight/daylight-info/broken-reference) before running a simulation. For the Metric, inputs must be configured per Green Star's requirements. See your Greenb Star documentation for up-to-date information.