New Study: Home Energy Savings Are Made in the Shade

May 6, 2009
Shade trees positioned near houses in Sacramento, Calif., such as those in this photo, can significantly affect electricity use. Tree cover on the west and south sides of Sacramento homes reduced average summertime electricity demand by more than 5 percent, according to a study by NIST and the USDA. Credit: NIST

(PhysOrg.com) -- Trees positioned to shade the west and south sides of a house may decrease summertime electric bills by 5 percent on average, according to a recent study of California homes by researchers from the National Institute of Standards and Technology and the U.S. Department of Agriculture.

The first large-scale study of its kind, the research paper considers the effects of shade on 460 single-family homes in Sacramento during the summer of 2007 and provides hard statistics showing how well-placed shade can reduce and atmospheric carbon, as well.

“People have known for a long time that trees have multiple benefits for people, but we’ve quantified one of them for the first time using actual billing data and put a dollar value on it,” said NIST’s David Butry, who authored the paper with Geoffrey Donovan of the USDA Forest Service’s Pacific Northwest Research Station.

The study’s findings included:

• Planting trees on the west and south sides of a house decreased summertime electricity use, but planting them on the north actually increased it. Those on the east had no effect.

• Fast-growing trees provide better help than do smaller ones, and placement of the trees, particularly the distance from the house, is a significant factor.

• A London plane tree, planted on the west side of a house, can reduce carbon emissions from summertime electricity use by an average of 31 percent over 100 years.

This last finding was particularly significant to Butry, who said that trees not only reduce the carbon produced by the local gas or coal-fired power generator, but also remove carbon dioxide—a greenhouse gas—from the atmosphere.

“Trees sequester carbon in addition to providing shade,” Butry said. “We measured how much these reduced the carbon created by burning fuels to produce the electricity, and found that the trees also sequestered an equivalent amount of carbon on top of that. So there’s a double benefit.”

Utility companies from as far away as South Korea and South Africa have contacted the team about expanding the study, which was limited to a single season in a single city.

“It would be really interesting to look at how the effect varies across regions of the U.S. and of the world, and to see what happens in wintertime,” Butry said. “Sacramento Municipal Utility was very helpful in providing us with the data we needed. But future studies will depend on who has data and shares it with us.”

More information: G.H. Donovan and D.T. Butry. The value of : Estimating the effect of urban trees on summertime electricity use. Energy and Buildings June, 2009, 662-668. doi: 10.1016/j.enbuild.2009.01.002.

Provided by National Institute of Standards and Technology (news : web)

Explore further: Study: Amazon trees older than believed

Related Stories

Shade Tree Coverage Reduces Power Costs

November 15, 2008

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

Recommended for you

Smart home heating and cooling

August 28, 2015

Smart temperature-control devices—such as thermostats that learn and adjust to pre-programmed temperatures—are poised to increase comfort and save energy in homes.

Smallest 3-D camera offers brain surgery innovation

August 28, 2015

To operate on the brain, doctors need to see fine details on a small scale. A tiny camera that could produce 3-D images from inside the brain would help surgeons see more intricacies of the tissue they are handling and lead ...

Team creates functional ultrathin solar cells

August 27, 2015

(Phys.org)—A team of researchers with Johannes Kepler University Linz in Austria has developed an ultrathin solar cell for use in lightweight and flexible applications. In their paper published in the journal Nature Materials, ...

Interactive tool lifts veil on the cost of nuclear energy

August 24, 2015

Despite the ever-changing landscape of energy economics, subject to the influence of new technologies and geopolitics, a new tool promises to root discussions about the cost of nuclear energy in hard evidence rather than ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.