Auburn University study: Shade trees can reduce power bills by 11.4 percent

AUBURN – An Auburn University study sheds new light on just how valuable shade trees are in reducing homeowners’ electricity bills during hot summer months.

Professor David Laband in the Auburn University School of Forestry and Wildlife Sciences says electricity usage and costs will be 11.4 percent less if a house has just 17.5 percent heavy shade coverage. This is compared to a house with no shade.

“The keys are heavy foliage and late afternoon shade,” Laband said. “The savings can be very significant for homeowners. Over the years I had read statements that shade trees reduce electricity consumption, so we wanted to put a dollar amount to it.”

His office conducted a yearlong study of 160 houses in the Auburn area to determine the annual energy savings provided by shade trees, primarily looking at the months of May to September. He analyzed power bills, calculated shade coverage and surveyed the homeowners about household makeup, electricity-usage habits, square footage, type of air conditioning, appliances, roofing, exterior material and other factors.

“We looked at the amount of shade in the early morning, early afternoon and late afternoon,” Laband said. “If you have trees on the west side of your house, you will have a much lower power bill.”

Using local power company rates for kilowatt hours per day, Laband said the 11.4 percent savings would equal $31 to $33 per month. The study, which categorized types of shade into light, moderate and heavy, also found that a house covered with 50 percent of light shade will save 10.3 percent.

Thermostat settings were important as well. “For each degree you raise your thermostat, you will save 3.3 percent on your power bill,” he said. “We also found that children under age 12 are the major power consumers in the home. They watch television, play games and leave lights on.”

Laband hopes the study will encourage real estate developers not to cut down all the trees on new lots.

“Many older houses have large trees around them because the owners did not rely as much on air conditioning then,” he said. “Houses today often do not have shade trees because it’s easier to run an air conditioner. This study shows how much can be saved when trees are used in yards.”

Auburn’s study was funded by a $116,000 grant from the USDA Forest Service’s Urban and Community Forestry Program and a matching $116,000 grant from Auburn’s School of Forestry and Wildlife Sciences.

Laband has briefed USDA officials on the results and has presented seminars in Australia at the Tropical Forest Research Institute, the University of Melbourne and the University of Adelaide.

“It gets very hot there, too,” he said. “They are interested in doing a similar project.”

Laband, who earned his Ph.D. in economics from Virginia Tech in 1981, conducts research and teaches on topics related to economics and policy, with a focus on natural resources. He joined the Auburn University faculty in 1994 and the School of Forestry and Wildlife Sciences in 2000, where he is a member of the Center for Forest Sustainability and the Forest Policy Center.

(Written by Charles Martin.)

Contact: Charles Martin, (334) 844-9999 (marticd@auburn.edu), or
Mike Clardy, (334) 844-9999 (clardch@auburn.edu)

14 thoughts on “Auburn University study: Shade trees can reduce power bills by 11.4 percent

  1. Judy Allen

    The article about the shade trees is EXCELLENT. Now, I know where to plant additional trees in my yard. THANKS, Judy

  2. John

    Really, $116,000 to figure out that shade trees make things cooler and saves energy? I could have told you that so where is my money?

    They may reduce power bills by 11.4%, but how much do they increase home owner’s insurance premiums because of storms that blow trees down onto people’s houses?

  3. JB

    Trees do not increase you insurance rates. You will pay the same rates if you have no trees. You have a greater chance of a claim if you have trees, but you have to decide if you are willing to take the risk

  4. Sara

    I found this study to be helpful because I find anything that encourages homeowners to plant more trees is a positive! Some people only look at the bottom line, and if this makes tree-planting more palatable to them, then it’s money well spent.

  5. Jenn

    The short term investment of this study will yield monetary gains (savings) for numerous families, saving electricity and costs in the long-run…and with our economic/environmentally fragile world, dissemination of this information is key to helping everyone save money and to improving our planet’s well-being (trees do more than just save us money on electricity bills).

  6. Marie A

    Well, my insurance has a 2% named storm deductible. My house is worth $270,000, so my deductible is $5600. I know this because I looked it up when Gustav blew through and leaned the fence and made the roof leak, and ripped off vinyl soffit. I tried to make a claim but the damage was equal to my deductible, so I am stiffed the loss. So if that huge tree in the back yard on the west side of my house had fallen on my house during the hurricane, would it have saved me $5600 in utility bills by now? Nah, I think I’m still going to get it cut down, cause the next hurricane that blows through might have winds coming from the west like Katrina did. I’ll take an 11% higher utility bill over a tree through the roof anyday. So can I get some free money for my analysis, say about $5600?

  7. Ryan

    Do they publish the budget online? I would like to know where the money went also. Power bills are free to observe. Someone got a nice Holiday Bonus the past two years.

  8. Joe B

    Ask all the homeowners on the gulf coast who suffered losses from Katrina, Rita, Gustav, and Ike if the want to plant more trees. I really don’t think so, alt least not the huge trees that provide the shade you are talking about. MY brother-in-law lost 26 of those beautiful trees and his insurance company paid for removal of 2 of them because they fell on his boat. The rest were on him, because they fell on the ground and didn’t damage any property. Do you know how much it costs to plant a tree as compared to how much it cost to have it removed from your property? I don’t think he will be planting any more trees.

  9. Matt

    If you all have questions (which some of them are good), then why don’t you contact the writer of the article, Charles Martin, (334) 844-9999 (marticd@auburn.edu), or the professor that did the study, Dr. David Laband, (334) 844-1074? If you have questions or concerns, great. But if you really want to accomplish something, then actually call those doing the research.

    Joe B: Of course it’s not a good idea for those living in areas highly prone to wind damage. Suppose there had been a study that said large windows all over your house lead to the greenhouse effect, which would warm your house and save power in the winter. Would it be a good idea for someone living in earthquake prone areas of California to build a house with tons of windows? No. Does that mean the study is any less valid or useful for people living in areas not prone to earthquakes? No.

  10. Pingback: Shade trees slash power bills | greenrightnow.com

  11. clyde

    reading the negative response based on the trees being toppled by hurricanes, i have to wonder how many thousands of homes enjoy the benefit of shade trees with no adverse effect for each one house that is damaged by a fallen tree. as matt points out, that mentality would lead one to build a concrete block home, no windows, metal door miles away from any object that could cause damage if hurled from a hurricane or tornado. better yet, move into a cave or head to the desserts of arizona.

  12. Forester

    Nina: In case you haven’t looked around lately, most shade trees are deciduous. They drop their leaves in the fall and have minor negative impacts on home heating costs. If someone wants to give me $200,000 I’ll prove it.

  13. Neil

    Most decisions about urban trees should always weigh costs and benefits. Anecdotes may help, but research like this is essential to help people decide when, where, and what (if any) trees to plant or retain near their homes. As far as storms and urban trees are concerned, research (again) is showing how to make urban trees more storm resilient through pruning and species selection. The bottom line is that good research like this will make it possible to improve our communities for people through urban trees.

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