Maybe but I can tell that is not my case. If I was to generalize my question beyond my circumstances it would. What coatings should be used for roof and exteri

Maybe but I can tell that is not my case. If I was to generalize my question beyond my circumstances it would. What coatings should be used for roof and exterior walls for a well insulated building in in the mid forties latitude. Snow has some insulating value so the heatloss is reduced. A highly absorbent roof might still be a plus. I'm currently trying to figure out the if I can put a thin layer of phase change material PCM on my exterior walls. The idea would be that the phase change would delay the reaction of the heat transmission through the walls. The building has a high thermal mass and it takes about 72 hours of a 15+ degree temperature difference to result in 4 degree temperature change of the interior of the building. Modern commercial buildings can't use open windows for ventilation. The ventilation has to be provided by a mechanical system. I'm trying to optimize the building to maintain a consistent overall temperature range of 72-78 degrees. The summer is not a problem the heat pumps and solar array mean I only get 5 electric bills a year. I think that I can do a lot of optimization of coatings and solar thermal to get to net zero.