Straight Talk Articles
Energy Efficient Trees? How Landscaping Can Help Your Energy Bill
Dear Pat: This year, I am planning a re-design of my yard. Are there features I can incorporate outside that would help my home be more comfortable inside? – Nancy
Late winter and early spring is a great time to think about changes you want to make in your yard and garden. While the goal of most landscaping projects is to bring beauty to your outdoor space, a well-designed project can also improve your energy bill, increase your overall home value, and provide other benefits such as reduced noise pollution, optimized water usage, and cleaner air around your home.
The two biggest strategies for improving the energy efficiency of your home with landscaping are to incorporate shading in the summer and wind blocking in the winter.
Summer Shading: According to the U.S. Department of Energy, shading your home is the most cost-effective way to reduce heat gain from the sun and reduce your air conditioning costs in the summer. Just having more plants and trees in your yard can reduce the air temperature by up to 6’F over nearby treeless areas.
Planting deciduous trees on the south, south-west, and west sides of your home can be very effective at cutting heat to your home during hot summer months, while allowing sunlight through in the fall and winter, when the trees have lost their leaves. When placing trees, consider the expected shape and height of the mature trees and where they will shade your home. For example, a tree with a high mature height planted on the south side of a home will provide maximum all-day roof shading in the summer, while a lower tree on the west side of your home can protect your home from the lower afternoon sun. Plant trees an appropriate distance away from your home so that they do not disrupt your foundation or your roof as they grow. While it will be five to ten years before a newly planted tree will begin providing shade to your roof, it can start shading windows immediately. Incorporate other plants to provide near-term shade: shrubs, bushes, and vines can quickly shade windows and walls.
Also consider any paved areas around your home and how you can shade them during the summer. Think about walking across your driveway barefoot on a hot July day—if your driveway or patio is unshaded, it is probably quite difficult. That absorbed heat is also reflecting onto your home, causing your air conditioning to work harder. You can use trees, hedges, and other landscaping structures such as arbors to shade these paved areas.
Wind blocking techniques: If your home is in an open area without many structures around it, cold winter winds may be increasing your heating bills. A windbreak on your property can help deflect these winds over your home. The most common type of windbreak uses a combination of conifer trees and shrubs to block wind from the ground to the top of your home. For the best windbreak effect, plant these features on the north and northwest sides of your home and at a distance from your home of between two and five times the height of the mature trees. Incorporating a wall or fence can further assist with the wind break.
Another insulating technique is to plant shrubs and bushes closer to your home, but at least one foot away. The space between these plants and your home is “dead air space”, which helps insulate your home in both the winter and summer.
The particular landscaping strategies you should focus on will depend on your climate zone. For example, if you live in a hot, arid climate, you should focus on maximizing shading to your roof and windows for much of the year, while a home in a home in a hot, humid climate will want to maximize summer shade. Regardless of where you are located, if you live near powerlines, talk with your co-op about how far away newly planted trees should be from these lines before making any final design decisions in your yard.
This column was co-written by Pat Keegan and Amy Wheeless of Collaborative Efficiency.
For more ideas on energy efficient landscaping, visit the March 2017 More Information page.