Christie ? it?s kinda hard to evaluate possible causes without more details, but I can suggest a few things:

The % number and the ?Hours above/below? figures on BEPS/BEPU are on different metrics, IIRC (?% of hours fans on? vs. ?hours of the year?). That they disagree to this extent may mean you have many ?undercooled? hours occurring when you?ve dictated the fans are off. You should be able to identify which zones are having the trouble, then for a specific zone in which hours of the day those are occurring between the different SIM reports ? I can?t recount which ones exactly from memory, but SS-R/F/O comes to mind ? maybe others??

If that?s the case, then it could be a simple matter of reviewing your t-stat setpoints in the respective schedules and ensuring setback temps are happening when you intend them to. You might also ask yourself what should be happening with regard to morning warmup and see if that?s reflected in your model as well.

If the underheated/cooled hours are occurring in the middle of the day ? that may conversely be a sign of inadequate capacities (heating/cooling/airflow), in which case I?d start by reviewing airflow-related scheduling and specified quantities.

The ?detailed simulation reports summary? PDF under the help menu is a good starting point to help you see what clues the SIM reports can give. Note you can ?ctrl+f? through it to find topics/reports of interest.

Try seeing what you can learn from the SIM reports, and post again with your findings if after that you?re still stuck for ideas as to what might be off ;).

~Nick

NICK CATON, P.E.