Some jurisdictions across the US are starting to address the heat island effect by instituting various requirements for cool roofs and pavements. It also appears that they are using this pilot credit for cool walls as well. The base research for requirements for walls was developed in Los Angeles and doesn't appear to be applicable for cold climates. Unfortunately, this pilot credit doesn't give any guidance for which climate zones this is appropriate for. Should there be limitations for cool walls in this pilot credit?
The research paper “Measured Cooling Energy Savings from Reflective Wall Finishes: Evaluation as an Efficiency Measure across Climates” by Danny S. Parker, FSEC Energy Research Center, University of Central Florida, does not support that Northern climates will benefit from cool walls. As stated, "With simulations we corroborated the finding of Petrie et al. (2007) that reflective walls are unhelpful in heating dominated climates such as Baltimore, Minneapolis and New York City. Essentially, if the ratio of cooling degree days to heating degree days is less than 0.9, there seems little advantage for more reflective wall surfaces."