Although the use of cool roofs is more or less universally accepted as being beneficial in southern climates, some have questioned the merits of using them in northern regions. Specifically some have reservations as to whether or not net energy benefits can be achieved using cool roofs in colder locales, and postulate that cool roofs are more prone to condensation than alternative materials. Although a number of articles and papers have been written on these topics, they are typically based on opinions, hypotheses, and in some instances on some form of computer modeling. There is little, if any, information generated from actual buildings in operation presented.
Target Corporation has for approximately two decades installed, almost exclusively, white, mechanically attached thermoplastic PVC roofing membranes on their retail stores as well as on their distribution centers and other facilities. These roof systems, which are typically installed over steel decks without a vapor retarder, have performed very well in all climates, and they are still to this day the base design for all of Target’s facilities.