OpenBuildings Energy Simulator displays values and quantities in many locations throughout the application interface: the tool settings window, various data managers, databases, calculation and simulation results, and project data properties.

For each quantity, units are displayed using the default system of units that was defined for the project. For instance, a project located in the United States of America, the units system may be defined to display all quantities using the Imperial (IP) units system. If the project is located in Britain, the units system would be set to the Metric (SI) system.

Preferred units systems for the application (for all projects) are defined in the Defaults Manager dialog, but can be changed for individual projects in the Project Properties dialog.

This does not mean that the application is restricted to display units using only the systems defined for projects. Every quantity can be displayed using multiple units by selecting the alternative unit system from a drop-down list next to the value.

The following are examples of unit display options: