> For the complete documentation index, see [llms.txt](https://bombyx.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bombyx.gitbook.io/docs/components/0-database/4-building-systems.md).

# 4: Building Systems

This component returns the environmental impact values for a specific building system based on the values in KBOB.

**INPUTS:**

The building system can be selected by the [Item Selector](/docs/components/0-database/item-selector.md) from the [System Groups](/docs/components/0-database/3-systems-groups.md) list.

Additionally, the system sizing should also be provided. This value will be multiplied by the impact factors.

> **NOTE:** In the case of services which have other units than ERA (Gerät, Stk., Kollektorfläche, or Max. Leistung), the units for the services can be seen in the [KBOB Database](/docs/databases/kbob.md).

**OUTPUTS:**

System properties (Text) provides the impact headers and values together for better readability, and System properties (Values) is the output that should be used through the workflow.