Housing expert offers ways to reduce air conditioning costs

Kenneth Gautreaux, Reichel, Claudette H.

Claudette Reichel, LSU AgCenter housing specialist, assembles a solar screen designed to reduce heat from the sun entering through a window. Solar screens are relatively cheap and easy for homeowners to construct. They can reduce up to 70 percent of sunlight from entering a home. They also can be removed during the winter when the sun’s heat energy is advantageous. Photo by Craig Gautreaux

A Bahamas-style shutter is shown on LaHouse, the LSU AgCenter’s teaching and demonstration home in Baton Rouge. These shutters can help cool your home by providing shade to windows. This shutter is on the west side of the house. Photo by Craig Gautreaux

An air duct sealed with mastic is shown at LaHouse, the LSU AgCenter’s teaching and demonstration home in Baton Rouge. According to Claudette Reichel, AgCenter housing specialist, studies show that 20-30 percent of cooling is wasted in the attic because of air duct leaks. Mastic, a gooey paste, should be used to seal ducts – not duct tape. Photo by Craig Gautreaux

Claudette Reichel, housing specialist with the LSU AgCenter, points out the MERV rating on an air filter. For air conditioners to work more efficiently, Reichel said homeowners should regularly change the air filters. Pleated filters with an MERV rating of 8-10 are a good choice for most homes. Photo by Craig Gautreaux

News Release Distributed 04/09/15

BATON ROUGE, La. – The long, hot, humid summers in the Deep South can cause electric bills to skyrocket as people turn on their air conditioners for relief. LSU AgCenter housing specialist Claudette Reichel offers several ways to reduce costs.

Some of these cost-saving measures are simple and can be performed by the homeowner. Others are more complicated and require a qualified professional.

One of the easiest is to change air filters routinely before they become dirty and restrict airflow.

“Dirty filters decrease efficiency leading to more energy usage,” Reichel said.

For most homes, pleated filters with an MERV 8-10 efficiency rating will keep the equipment and indoor air cleaner.

She also recommends having your air conditioner serviced by a professional at least every other year.

“Having the blowers and the coils cleaned will improve the efficiency of your unit. The service technician will also check the level of the refrigerant to make sure it is satisfactory,” Reichel said.

If your unit needs replacing, Reichel recommends homeowners do research on the products and learn some of the terminology. The SEER (seasonal energy efficient ratio) rating gauges the energy efficiency of the air conditioner. The higher the SEER rating, the more energy efficient the model is.

However, Reichel said, a unit with a very high SEER rating may not be the best option for Louisiana’s humid climate.

“Some models with high SEER ratings are designed for less humid climates and do a poorer job of removing humidity from our homes. High humidity levels in our houses make us more uncomfortable and lead homeowners to further lower the thermostat increasing energy usage. Also, high humidity can adversely affect air quality by supporting growth of dust mites and mold,” she said.

Split central air conditioning units sold in the in the southeastern U.S. must have a SEER rating of at least 14 as of Jan. 1, 2015. Reichel recommends consumers buy a SEER 15 or a little higher to increase efficiency and lower operating costs. Also, she said, consider variable capacity equipment that can achieve higher efficiency yet still have good dehumidification capacity.

Another important term to learn is the Energy Star label. This label indicates that the appliance is generally about 20 percent more energy efficient than the minimum requirements. Reichel said it is a good idea for consumers to look for the Energy Star label on all types of labeled appliances and not just air conditioners. Consumers can learn more about Energy Star products at www.energystar.gov.

Another method for reducing cooling costs involves reducing heat gain from the sun.

Trees, especially those planted on the south, east and west side of the home can provide valuable shade.

Sun control product options for windows range from inexpensive solar screens that can be made and installed by the homeowner to high-end decorative awnings or Bahama shutters.

Solar screens are similar to the insect screens on windows except they have smaller holes and can block up to 70 percent of the sun. They can be built by the homeowner or a professional and can be removed during the winter. A drawback of the screens is they also reduce the amount of light entering the home and alter the exterior appearance of windows, Reichel said.

Solar films are available with or without tinting. Look for the film’s solar heat gain coefficient (SCGC). This rating measures how well a product blocks heat from the sun and is expressed as a number between 0 and 1. The lower the number, the better the product is at reducing heat gain. A film with a SGHC of .3 means that it blocks 70 percent of the unwanted heat gain.

Also, look for the term “low-e” on the label, Reichel said.

“A homeowner can apply this product, but it can be a little tricky. Start with a small, inconspicuous window to see how good you are at it. If you don’t like the look of it, you may want to hire a professional,” Reichel said.

“The good thing about today’s solar films is that they can allow more visible light to enter the home than tinted films or shade screens,” she said.

When replacing roofing, a more heat-reflective roof can save on cooling costs.

“There are metal roofs that have special pigments in the paint that reflect heat, so it doesn’t necessarily limit the homeowner to only lighter colors.” She said to look for the Energy Star on roofing materials.

Reducing wasted air conditioning in a vented attic is another way Reichel said homeowners can save.

“Twenty to thirty percent of cooling is lost in the typical attic through leaks at the joints of ducts and by heat gain from the hot attic, which is often much hotter than the outdoors,” she said.

She recommends having a professional come in with specialized duct leakage testing equipment that can pressurize the ducts to measure air leakage. When the leaks are identified, they should be sealed with UL mastic (a gooey paste) and not duct tape, she said.

“Another way to reduce heat gain in the attic and the duct work is to install a radiant barrier,” Reichel said. “Radiant barriers are similar to aluminum foil in how they block radiant heat but are reinforced to resist tearing.”

A radiant barrier can be installed by the homeowner by simply stapling it across the rafters, leaving gaps at the roof ridge and overhangs to retain attic ventilation. However, Reichel said, this must be done with the shiny side facing down and the inside of the attic to avoid collecting dust for it to work effectively over time.

Controlling moisture in the home is often overlooked as a way homeowners can keep comfortable in the summer.

“Anything done to reduce inside humidity is helpful to the homeowner. It feels more comfortable and reduces your cooling load and costs,” Reichel said. “Good exhaust fans in the kitchen and bathrooms that are properly vented to the outside help remove excessively humid air.”

Reichel also noted that good drainage away from the home helps reduce moisture that migrates through the foundation thus leading to more moisture within the home.

Reichel said that most of these energy saving methods can be seen at the LaHouse Home and Landscape Resource Center on the LSU campus in Baton Rouge. LaHouse is on Gourrier Avenue, just off Nicholson Drive, and across the street from Alex Box Stadium.

LaHouse is open to the public Monday through Friday from 10 a.m. to 4:30 p.m. A Saturday Open House is held four times a year. The next one is April 18 from 10 a.m. to 2 p.m. in celebration of Earth Day.

She also said that if homeowners are interested in installing solar panels on their homes, the AgCenter has released a new guide on solar energy. It can be found at www.lsuagcenter.com/solarpub.

For more information, videos and photos about ways to enjoy the benefits of a high-performance home, go to www.lsuagcenter.com/LaHouse.

Craig Gautreaux

4/9/2015 9:14:06 PM
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