As per the latest BCBC and VBBL requirements, ASHRAE-Checklist 90.1 201 is mandatory to be submitted for projects that require AHSRAE compliance. There are three building envelope compliance methods under ASHRAE 90.1:

Building Energy Modeling


(in which the building envelope thermal values are pre-defined) can only be used when the building has less than a 40% window-to-wall ratio and less than 5% skylight to roof ratio.


The R-Value of the different elements is adjusted to cover for the weaker elements (e.g.. more insulation on the roof to cover heat loss through the windows). This method only helps to balance the heat loss through assembly and thus there might be other potential design concerns associated (e.g.. condensation control).



Is potentially more effective for buildings that have more than 70 to 80% window-to-wall ratio (usually high-rise buildings). This method reviews the building as a system, taking into account the building envelope assemblies and the mechanical and electrical systems.

Using sophisticated software, CCIG’s (now McIntosh Perry) team of Energy Modeling experts can determine a building’s energy  model to help in the design and performance of a building. For more information on how we can help you with building energy modeling or other building science services, call us toll free at 1-888-348-8991, or:


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