Cold Climate

Can you elaborate on your goal for an alternative compliance path? The intent of the LEED credit is to minimize effects of surface warming (heat island) by utilizing roofing materials that reject solar heat. This overall sustainability concept would be applicable in all climates.

We've tried to argue for years that most cold climate buildings are not near other structures, and in heating mode year-round. The benefit to a black roof is greater than the benefit of a white roof... We have been instructed that the benefit will show itself in EAc1, and you will have to forgo the SSc7.2 credit.

I'm not sure I understand your position. For a start I don't agree with your statement that "most cold climate buildings are not near other structures.." , and although it's reasonable to assume they will not be "in heating mode year-round", I'm unclear on how either statement supports your the argument for the benefits of black roofs...am I missing something?

While it's true that not all structures in cold climates are not near other buildings, many are separated by large distances (acres of open area between buildings) that don't allow heat islands to form. Black roofs provide more solar heat gain to the building. With the absence of a cooling load, a white roof creates less heat gain; therefore, more fossil fuels are burned to heat the building when a passive strategy with a black roof would add a degree or two to the interior. Additionally, white roofs take longer for ice and snow to melt, leading to "free cooling" of the building while in heating mode. The same goes for hardscapes. Having highly reflective surfaces is a bigger safety issue than heat island issue (again assuming you aren't in one of the few northern cities). In winter, it is covered with that hard pack layer of snow/ice. In the swing season, it is better to have black surfaces capable of melting snow/ice.

I would assume that not being to guarantee that future infill would not eventually lead to a condition where heat island could form, was part of the USGBC considerations. I'm not sure, again this is dependent on the region, that the energy saved in the winter offsets the cooling load required in the summer. You make a very good point about snow/ice melt, but again it could be argued, that snow cover on a roof has an insulative effect.