Energy

Large and strategically placed trees in urban areas can effectively reduce energy costs and demands. Just three well-placed trees around a home can decrease utility bills by 50%, lower air conditioning bills by up to 30% and can save up to 25% on winter heating costs (SDDA, 2008). Neighborhoods with well-shaded streets can be up to 10 degrees cooler than neighborhoods without street trees.

In the summer, trees affect energy consumption by shading buildings, allowing air conditioning units to run more efficiently and providing evaporative cooling . Shade from large trees is more effective at cooling a building than window blinds because trees block sunlight that may heat a building and reduce air temperatures around the building. West-shading plants have the greatest ability to reduce cooling needs, especially during peak energy demands in the afternoon.

The location of the trees, their size, and distance from the building affect the impact on energy use. Generally, trees affect building energy use when they are greater than 20 feet tall and within 60 feet of a building. Deciduous trees shading the southwestern sides of buildings in the summer will drop their leaves and allow the sun to provide warmth in the winter. Strategically placed trees also reduce winter heating costs by blocking cold winds.