The impact of trees and white surfaces on residential heating and cooling energy use in four Canadian cities

We have investigated the potential of using vegetation and high-albedo materials in Toronto, Edmonton, Montreal, and Vancouver, Canada, to modify the urban microclimate, thereby saving residential heating and cooling energy use. Parametric computer simulations of microclimates and energy performance of prototypical houses were our primary analysis tools. The building prototypes included a detached one-story and a detached two-story single family house, as well as a row house. The simulations indicated that by increasing the vegetative cover of the neighborhood by 30% (corresponding to about three trees per house) and increasing the albedo of the houses by 20% (from moderate-dark to medium-light color), the heating energy in Toronto can be reduced by about 10% in urban houses and 20% in rural houses, whereas cooling energy can be reduced by 40 and 30%, respectively. The annual savings in heating and cooling costs for different houses ranged from $30 to $180 in urban areas and from $60 to $400 in rural zones. In urban houses of Edmonton, Montreal, and Vancouver, savings in heating energy use were about 10%. Cooling energy can be totally offset in Edmonton and Vancouver, and average savings of 35% can be achieved in Montreal.