Roofs always have been a major focus for building energy-conservation measures. The emphasis traditionally has been on beefing up insulation. More recently, advances in roofing materials technology and analytical techniques have found new ways to fine-tune the energy performance of roofing to reduce not only operating costs, but also environmental impact. The so-called "cool roof" is one of these. A cool roof minimizes the solar heat gain of a building by reflecting the bulk of incoming radiation and then quickly re-emitting the remaining absorbed portion. The cool roof stays cooler than traditional construction, minimizing the transfer of heat to the building below. Cool roofing is not without controversy. Some studies have shown that reflective roofs are not always best in cool climates, where low emissivity could benefit heating systems in cold weather. Potentially damaging condensation within a roofing assembly also can be aggravated in such climates because of the enhanced temperature differential between the warm interior and the cooler roof. This can be of particular interest for designers and facility managers of education institutions, which often are closed during the summer months and thus experience minimal air-conditioning demand for cool roofing to leverage against.