Landscaping For Energy Savings
Are you looking for cost-effective yet eye-pleasing ways to lower your energy bills? Planting trees, shrubs, vines, grasses, and hedges could be the answer. In fact, landscaping may be your best long-term investment for reducing heating and cooling costs, while also bringing other improvements to your community.
Landscaping is a natural and beautiful way to keep your home more comfortable and reduce your energy bills. In addition to adding aesthetic value and environmental quality to your home, a well-placed tree, shrub, or vine can deliver effective shade, act as a windbreak, and reduce overall energy bills.
A well-designed landscape will:
Cut your summer and winter energy costs dramatically.
Protect your home from winter wind and summer sun.
Reduce consumption of water, pesticides, and fuel for landscaping and lawn maintenance.
Help control noise and air pollution.
Landscaping Saves Money Year-Round
Carefully positioned trees can save up to 25% of a household's energy consumption for heating and cooling. Computer models devised by the U.S. Department of Energy predict that the proper placement of only three trees will save an average household between $100 and $250 in energy costs annually.
On average, a well-designed landscape provides enough energy savings to return your initial investment in less than 8 years. An 8-foot(2.4-meter) deciduous (leaf-shedding) tree, for example, costs about as much as an awning for one large window and can ultimately save your household hundreds of dollars in reduced cooling costs, yet still admit some winter sunshine to reduce heating and lighting costs. Landscaping can save you money in summer or winter.
You may have noticed the coolness of parks and wooded areas compared to the temperature of nearby city streets. Shading and evapotranspiration (the process by which a plant actively moves and releases water vapor) from trees can reduce surrounding air temperatures as much as 9 degrees F (5 degrees C). Because cool air settles near the ground, air temperatures directly under trees can be as much as 25 degrees F (14 degrees C) cooler than air temperatures above nearby blacktop. Studies by the Lawrence Berkeley Laboratory found summer daytime air temperatures to be 3 degrees F to 6degrees F (2 degrees C to 3 degrees C) cooler in tree- shaded neighborhoods than in treeless areas.
A well-planned landscape can reduce an un-shaded home's summer air conditioning costs by 15% to 50%. One Pennsylvania study reported air-conditioning savings of as much as 75% for small mobile homes.
You may be familiar with wind chill. If the outside temperature is 10degrees F (-12 degrees C) and the wind speed is 20 miles per hour (32kilometers per hour), the wind chill is -24 degrees F (-31 degrees C). Trees, fences, or geographical features can be used as windbreaks to shield your house from the wind.
A study in South Dakota found that windbreaks to the north, west, and east of houses cut fuel consumption by an average of 40%. Houses with windbreaks placed only on the windward side (the side from which the wind is coming) averaged 25% less fuel consumption than similar but unprotected homes. If you live in a windy climate, your well planned landscape can reduce your winter heating bills by approximately one-third.
Landscaping for a Cleaner Environment
Widespread tree planting and climate-appropriate landscaping offer substantial environmental benefits. Trees and vegetation control erosion, protect water supplies, provide food, create habitat for wildlife, and clean the air by absorbing carbon dioxide and releasing oxygen.
The National Academy of Sciences (NAS) estimates that urban America has 100 million potential tree spaces (i.e., spaces where trees could be planted). NAS further estimates that filling these spaces with trees and lightening the color of dark, urban surfaces would result in annual energy savings of 50 billion kilowatt-hours—25% of the 200 billion kilowatt-hours consumed every year by air conditioners in the United States. This would reduce electric power plant emissions of carbon dioxide by 35 million tons (32 million metric tons) annually and save users of utility-supplied electricity $3.5 billion each year (assuming an average of $0.07 per kilowatt-hour).
Also, some species of trees, bushes, and grasses require less water than others. Some species are naturally more resistant to pests, so they require less pesticides. Another alternative to pesticides is integrated pest management, an emerging field that uses least-toxic pest control strategies. One example is to introduce certain insects such as praying mantises or ladybugs to feed on—and limit populations of—landscape-consuming pests.
Certain grasses, such as buffalo grass and fescue, only grow to a certain height—roughly 6 inches (15 centimeters) and are water thrifty. By using these species, you can eliminate the fuel, water, and time consumption associated with lawn mowing, watering, and trimming. Also, recent studies have found that gasoline-powered mowers, edge trimmers, and leaf blowers contribute to air pollution.