If loads are not met for more than 300 hours, the software shall require the user to change the proposed design building description to bring the UMLH equal to or below 300. This process might not be automated by the software, in which case the user is required to modify the design model to bring the UMLH within acceptable limits. Two tests must be met:
- Space loads must be satisfied and space temperatures in all zones must be maintained within one half of the throttling range (1°F with a 2°F throttling range) of the scheduled heating or cooling thermostat setpoints. This criterion may be exceeded for no more than 300 hours for a typical year.
- System loads must be satisfied: Plant equipment must have adequate capacity to satisfy the HVAC system loads. This criterion may be exceeded for no more than 300 hours for a typical year.
Equipment sizes for the proposed design shall be entered into the model by the energy analyst and shall agree with the equipment sizes specified in the construction documents. When the simulations of these actual systems indicate that specified space conditions are not being adequately maintained in one or more thermal zone(s), the user shall be prompted to verify the model inputs to reduce the number of UMLHs.