Cool surface technologies, urban vegetation, and their effects on energy and air quality in Canadian climates

在夏季，凉爽的屋顶反射了大部分入射的阳光，减少了通过屋顶的热传导。同样，战略性地放置树木，遮阳窗户和建筑物的墙壁减少了直接的热量获得。夏季热量增加的减少减少了建筑物的空调负荷，提高了舒适度，节省了高峰用电需求，并节省了资金。在冬季，凉爽的屋顶和遮荫的树木可能会增加建筑物的热负荷，然而，热能损失相当小（树木实际上可以通过保护建筑物免受冷风的影响来节省热能费用）。

During the summer, cool roofs reflect most of the incoming sunshine and reduce heat conduction through roofs. Similarly, strategically placed trees, shading windows and walls of a building reduce the direct heat gain. The reduction in summer heat gains reduces the air-conditioning load of a building, improves comfort, saves peak demand electricity, and save money. During the winter, cool roofs and shade trees may add to the heating load of a building, however, the heating energy penalties are fairly small (trees can actually save heating energy bills by shielding a building from cold wind).