We are doing the energy model for Office space which has registered under LEED ID+C v4. The overall floor area of the project space is 45,000 Sq.ft & the overall floor area is 1,20,000 Sq.ft. Conditioned area of project space is 38,000 Sq.ft & the overall conditioned area is 1,00,00 Sq.ft. This is G+4 Floors building.

As per Baseline Energy Model/Appendix G,

                The baseline system is system 6 – PVAV with PFP Boxes & we have considered one system per floor. However, we have decided to consider exception of G3.1.1

c. If the baseline HVAC system type is 5, 6, 7, 8, 9, 10, 11, 12, or 13 use separate single-zone systems conforming with the requirements of system 3 or system 4 (depending on building heating source) for any spaces that have occupancy or process loads or schedules that differ significantly from the rest of the building. Peak thermal loads that differ by 10 Btu/h·ft2 or more from the average of other spaces served by the system, or schedules that differ by more than 40 equivalent full-load hours per week from other spaces served by the system, are considered to differ significantly.

For the above-mentioned exception, we have calculated the peak thermal load for all the conditioned spaces by considering the following energy model inputs/methods.

  1. Baseline system is 6
  2. Auto sized capacity (Cooling 1.15 & Heating 1.25)
  3. Supply air temperature difference is 20 deg F

Our software has provided the floor area and peak thermal load in KBTU/Hr. From these, we have calculated the BTU/Hr/Sq.ft. Also, we have compared each room’s BTU/Hr/Sq.ft with an average BTU/Hr/Sq.ft of rest of spaces.

Finally, we have found that which are the spaces are differing more than 10 BTU/Hr/Sq.ft.

Can this approach be correct?

Which system to be used for identified spaces? (System 3 or 4 or same 6)


80% of conditioned spaces are office, meeting & manager cabins

10% is corridors

10% - Elec, kitchen & storerooms.

We look forward to your kind response.