Optimizing landscape tree placement to conserve energy for heating and cooling residential structures

Abstract

Landscape trees can help reduce energy consumption by shading homes in summer and by blocking winds in winter. Because most modern homes have automated climate control, homebuilders and homeowners often do not give much thought to using landscape trees to conserve energy. When they do consider this, they often put trees in sub-optimal locations. We conducted a series of computer simulations to study the effects of tree form (size and shape) and tree placement (distance and direction from house) on energy consumption. We then examined existing landscape trees around recently constructed homes in three cities of contrasting climate (Minneapolis, MN; Charlotte, NC; and Orlando, FL). From the simulations, we learned that a large tree on the west aspect of a structure could decrease annual energy costs by up to 160 kWh (valued at $18) in southern cities with longer cooling seasons. In contrast, the same tree on the south aspect could increase annual energy costs by up to 134 kWh (−$15) in northern cities with longer heating seasons. When we modeled existing landscape trees in the three U.S. cities, we found that large-stature deciduous trees provided average annual energy savings per parcel of 14 kWh (MN), 25 kWh (NC), and 44 kWh (FL). By spatially reconfiguring these trees in a simulator, we were able to optimize the placement of over 70% of the trees and more than double the annual energy savings. These results suggest that homebuilders and homeowners are not taking full opportunity to save energy with landscape trees and that more outreach is needed to improve landscaping decisions.