ASHRAE 90.1 Reference

Unmet hours

"Unmet hours" of a building are the summation of the number of hours when the heating or the cooling set point temperature of a zone is not met either by the HVAC system or by the plant. The data is provided in the Summary report as:

 

Understanding/Interpreting/Calculating the number of unmet hours:

Example

When each zone is unmet in the specified hours as beside

 

Zone 1 unmet during hours: 6 8 14 16

Zone 2 unmet during hours: 6 8 12 16

Zone 3 unmet during hours: 7 8 12 13

 

Total number of unmet hours of the building: 7 hrs and not 12 hrs.

 

6 7 8 12 13 14 16

 

 

The above information on Unmet hours is sourced from a post by Ashu Gupta (and subsequent posts) on the bldg-sim mailing list