ASHRAE 90.1.2010 and receptacle loads

The 25% minimum for process loads was never a requirement in LEED. The credit language was poorly written so it sounded that way but it was never the intent. Under v4 this part of the credit language was removed.

The 25% is a remnant left over when LEED was originally written around an office building. It was based on energy use data that showed that the typical office building's plug load was about 25% of the total energy use. It was/is used as a guideline in reviews. If you were over 25% then you were usually OK, if under 25% you had to provide an explanation as to why you were under.

What is most important is that you model the process loads (items that impact energy use but are not regulated by 90.1) as accurately as possible. An elementary school will be about 15%, an office 25%, a high rise office may be greater due to elevator use, add a restaurant to an office building and the percentage increases, etc.  High process load facilities like a refrigerated warehouse, data center, manufacturing plant, etc. will have 50% to 90% process.

LEED requires that you model all energy use within and associated with the project. The higher the identical process as a percentage of the total, the lower the overall savings. So under estimating the process is not a conservative estimate of savings. As a rule when in doubt always produce a conservative estimate of savings.

All process loads should be modeled based on the actual installed equipment or some reasonable data set like the 90.1-User's Manual or the COMcheck manual. So forget the 25%, model the process accurately and the reviewer will determine if you have done so in a reasonable manner.