Home Series Booklets

Make the most of your air-conditioning system

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During Iowa's hot, humid summers, about half of the heat that accumulates in a home comes from solar gain; the other half comes from air leaks and heat-producing activities inside the home. The time you spend reducing or eliminating conditions that add heat (and humidity) to your home will be well spent; the smaller the difference between the temperature outside and the temperature inside, the lower your annual cooling bill.

Take a tour of your home with the following list in hand, to discover what you can do to save energy and cut utility costs.

• Shade south and west windows to keep out the solar heat. Stopping the sun's warmth before it gets into your home with awnings or exterior solar screens is best. If that's not possible, close inside blinds and curtains during the day; light colors will reflect the most heat. As an alternative, apply tinted plastic sun-control films or reflective coatings to the inside of your windows.
• Keep the doors and windows closed during the day. But on cool, low-humidity nights, open the windows and use natural ventilation (with or without fans) to cool your home.
• Keep interior lights turned off or dimmed during daylight hours. However, turning on a table lamp for reading in a darkened room is a better choice than letting the sun stream in through a south or west window. On the other hand, north or east windows could provide enough light without significantly adding to the heat gain in an individual room.
• In high-use areas, replace incandescent lightbulbs with compact fluorescent units. Incandescent bulbs are very inefficient, using most of the energy they consume to create heat. A compact fluorescent lightbulb (CFL) produces the same light (and less heat) from 65 to75 percent less energy than a regular bulb-so a CFL can pay for itself during the life of the bulb.
• Turn off or unplug the television and other electronic equipment when not in use. Many video and audio components consume power and produce heat in the standby mode, so unplug them if you won't be using them for several days. The only way to turn off the power supply for a device such as a cordless phone or cable TV box is to unplug it.
• Minimize your computer's power consumption when you're not using it. Shut down your computer if you're not going to be using it for several hours. If you're just going to be away for a few minutes, turn off the monitor-it still uses considerable power in the "screen-saver" mode-and put the hard drive in your CPU to sleep.
• Construct a sunshade over a concrete patio. A concrete slab will become a large heat sink during summer months, reflecting sunlight and radiating heat into your house. A shading structure will solve both problems, as well as making the outdoor space more usable on hot days.
• If you're building a room addition, keep cooling in mind. Besides adequately insulating and weatherizing the new space, add 24-inch (or wider) overhangs to shade windows on the sunny sides of the new room. Also ask your contractor if your present cooling system can handle the additional load; if not, consider an energy-efficient supplemental system.
• Cover pots and pans on the cooktop or stove. Cooking creates lots of heat and humidity, so contain it as much as possible.
• Run your dishwasher late at night. Start the dishwasher when you go to bed. If it has a timer, set the dishwasher to run during non-peak hours in the middle of the night.
• Use the most energy-efficient appliances for cooking. Instead of using the stove or oven, use the microwave oven or a countertop appliance such as a toaster oven, crock-pot, steamer or pressure cooker.
• Replace old, inefficient appliances. Even if an appliance still has a couple of years of serviceable life, replacing it with an efficient, ENERGY STAR(r) qualified unit is a good investment.
• Use cold water for cooking. Heating the water on your stove or cooktop consumes less energy than using hot water from your water heater-especially if doing so causes your water heater to cycle.
• Check the temperatures in the refrigerator and freezer. The temperatures should run 38 to 40 degrees in the refrigerator and 0 to 5 degrees in the freezer. Setting colder temperature levels wastes energy and makes these heat-producing appliances run too often.
• Use exhaust fans in the kitchen and bathrooms. Vent steam and heat from cooking to the outdoors, and reduce humidity by running the fan while you're in the shower. However, don't let either one run too long, or they'll pull cooled air out of your entire house.
• Take shorter baths and showers. Long baths and steamy showers add a lot of humidity to your home and can increase the time your air conditioner runs to overcome it. Install a water-saving showerhead too.
• Vent your dryer outdoors. Check the lint trap, ducting and exterior vent frequently, to make sure they're clear. Excessive lint buildup can make your dryer run longer.
• Dry clothes on an outdoor clothesline. Wet clothes on an indoor clothesline will add humidity to your home and increase the load on your air-conditioning system.
• Use cold water for wash loads. Most clothes and other items will get clean in cold water, if you use the proper detergent. If you need to wash a warm- or hot-water load, run it during the late-evening or early-morning hours.
• Only wash full loads. If you don't have enough clothes for a full load, set the washer's water level to match the load's size.
• Build a utility room to enclose the water heater and laundry. Separating these heat producers from the rest of the house will reduce the load on your air-conditioning system. As a bonus, the rest of your home will be quieter too.

Sidebar

The material in this article was adapted from Home Heating and Cooling, a book published by the Iowa Energy Center. Besides offering more details on the topics discussed here, this publication also covers energy-saving home improvement projects that may be eligible for rebates from local utility companies; low-income assistance and grant programs; special financing opportunities from banks, credit unions and other lending institutions; state incentives; and federal income tax credits.

To get a free copy of this book:

• Call your utility company to see if you can stop by the office and pick up a copy;
• Download a PDF copy at the Iowa Energy Center Web site: http://www.energy.iastate.edu/homeseries;
• Request a copy by e-mailing the Iowa Energy Center at iec@energy.iastate.edu; or
• Call the Iowa Energy Center at 515-294-8819 to ask for a copy to be sent to you by mail.

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Contact:
Amy Myers, Iowa Energy Center, (515) 294-4391, myers@energy.iastate.edu