Under the 90.1 Performance Rating Method (PRM), the performance of the baseline building has to be based on the average of 4 separate rotations of the baseline building. This makes sense for new construction projects, as it makes the design team consider their choice of building orientation.
In the case of a buidling that is existing, such as a 100% gut-and-renovate project, there is no opportunity to change the orientation of the building. Is it then appropriate NOT to rotate the baseline building 4 times to generate its average performance?
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
962 thumbs up
May 24, 2010 - 3:50 pm
To meet Appendix G requirements, you still need to rotate the baseline in the model. The rewards projects with good orientation, regardless of the project's ability to influence the outcome.
Further, I would argue that even a gut reno should be considering orientation. One might consider different glazing types or shading schemes depending on orientation. Even program elements might be impacted by orientation. Areas with high process loads might not need the winter passive solar afforded by by a south exposure, etc.
Hans Wetterlund
Energy AnalystWSP Sverige
4 thumbs up
June 30, 2010 - 9:59 am
We too have this experiance but unfortunately no answer. The intensions in LEED is truly missLEEDing as we can not affect the Baseline Building electricity use, the major factor, I think, to the difference between 47 % and 22 % in your exampel, Michael.
In Ashrae handbook it is stated that the calculations can be based on energy cost OR energy performance so maby therefore we can use energy performance in LEED instead of energy cost, Chris??
Tristan Roberts
RepresentativeVermont House of Representatives
LEEDuser Expert
11474 thumbs up
July 1, 2010 - 10:45 pm
LEED specifically requires use of energy cost, for better or worse.