Making a home more eco-friendly should start with a quick inventory of your energy-guzzling appliances. According to the U.S. Department of Energy, residential use accounts for over one-fifth of all the energy consumed in the United States (see References 1). Windows, doors, insulation and the ways you use your appliances all contribute to your home's overall energy picture. Improvements in any of these areas will reduce energy bills and make your home "greener."
Assemble a list of the major energy-consuming appliances in your home. Systems like furnaces, air conditioners, water heaters, dishwashers and other larger items should be included. Refer to the owner's manual, the manufacturer or your local power company to check their rated energy consumption. Then compare against present standards for new devices. (See Resources 3, 4) The U.S. Environmental Protection Agency requires new gas furnaces, for example, to have an efficiency rating of at least 90 percent to qualify for the Energy Star label (see References 2). Older appliances may fall short of these standards. If so, calculate the cost of continuing to run your older devices compared to an upgrade.
Efficient windows retain heat in your home during the winter and block heat from entering during the summer. The U-factor and solar heat gain coefficient, SHGC, are the most important measures of how a window transmits heat energy (see References 3). Lower U-factors indicate higher overall energy efficiency, while lower SHGCs mean lower heat transmittal from outside to inside. Deciding which windows to select depends on whether you prefer to collect more solar heat, such as in colder climates, or block heat from entering in warmer climates. When building or remodeling a room, remember that, in the Northern Hemisphere, south-facing windows admit more solar heat than north-facing ones. Shades and blinds can also help control energy-flow through windows.
Insulation and Sealing
Air leaks and drafts from the outside can lead to substantial increases in energy use, with inadequate exterior insulation adding up to 20 percent to heating and cooling bills, according to the EPA (see References 4). The attic, roof and outer-facing walls are all important locations to insulate to prevent air and moisture infiltration. Insulation can be applied as rolls, sheets or spray depending on the dimensions of the insulated space (see References 5). Interior insulation of duct work is also critical for good climate control operation; duct leakage can lower system efficiency by up to 20 percent (see References 6).
Lighting consumes about 10 percent of the electricity used in an average home (see Resources 1). On the inside of a house, new halogen light fixtures typically use less energy than standard incandescents. In outdoor lighting, low-pressure sodium lamps are efficient when lighting needs to stay on for hours at a time (see Resources 2). With many other bulb types, motion detectors and light-sensitive photo sensors can automatically activate exterior lights as needed.
- Energy Information Administration: Energy Consumption by Sector Overview
- Energy Star: Furnaces Key Product Criteria
- U.S. Department of Energy: Energy Performance Ratings for Windows, Doors and Skylights
- U.S. Environmental Protection Agency: Air Seal and Insulate with Energy Star
- Oak Ridge National Laboratory: Wall Insulation
- U.S. Environmental Protection Agency: Benefits of Duct Sealing
Aaron Ziv has been a writer and photojournalist for 10 years in Washington, D.C., and the Middle East. A student of political science and psychology from the University of Maryland, he also does technical and market analysis for a green technology company. His work has appeared in local newspapers, commissioned research and a patent or two. He began writing professionally in 1998.
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