Energy Conservation - Conservation In The Residential And Commercial Sectors

Total building energy use in the United States has increased because there are increasing numbers of people, households, and offices. However, energy use per unit area (commercial) or per person (residential) has roughly stabilized over the past ten to twelve years because of a variety of efficiency improvements. The sources of energy in buildings have changed dramatically. Use of fuel oil has dropped, and natural gas has largely made up the difference. At the same time, other energy demands have risen. Electronic office equipment, such as computers, fax machines, printers, and copiers, has sharply increased electricity loads in commercial buildings. The Energy Information Administration (EIA) reported in its Annual Energy Review 2003 that energy use in the residential and commercial sectors accounted for an increasing share of total U.S. energy consumption: 29% in 1950, 33% in 1970, and 40% in 2003. (See Figure 1.9 in Chapter 1.)

Building Efficiency

There are several potential areas for research and development in energy conservation in buildings, which is where energy is used in the residential and commercial sectors. Among the techniques useful in reducing energy loads are advanced window designs, daylighting (letting light in from the outside by using high windows, skylights, and atria in the center of large buildings), solar water heating, landscaping, and tree planting. Energy conservation efforts in buildings have been substantial since the early 1980s.

Residential energy consumption can be reduced by introducing more efficient new housing and appliances, improving energy efficiency in existing housing, and building more multiple-family units. Residential energy consumption

FIGURE 9.6

is reduced as well when people migrate to the South and West, where the combined use of heating and cooling is generally lower than in other parts of the country.

In the residential sector, the amount of energy used in newer homes, particularly those built since 1980, is dramatically less than that used in older homes. The largest share of energy savings is the result of better construction, higher quality insulation, and more energy-efficient windows and doors. The Office of Technology Assessment reported in May 1992 (in Building Energy Efficiency) that roughly one-fourth the energy used to heat and cool buildings is lost through poor insulation and poorly insulated windows. Before the 1973 energy crisis, 70% of new windows sold were single-glazed (had only a single pane of glass). By 1990, because of changes in building codes and public interest, 80% of windows sold were double-glazed with double insulating ability, cutting energy loss in half. Double-glazed windows have two panes of glass sandwiched together with a small space in between. In addition, the glass may be specially treated or the space between the panes may be filled with a gas, either of which increases the insulating effectiveness of the window.

Energy consumption per household has remained fairly steady since 1982, as technology gains have been offset by an increase in the size of new homes and more demand for energy services. (See Figure 9.6.) As in the residential sector, improved technology has helped to slow the growth in commercial building energy use. Commercial buildings constructed after 1980 use considerably less energy than those built in the early part of the 1900s.

Home Appliance Efficiency

Overall, the number of households in the United States is increasing, which is increasing the demand for energy-intensive products and services like air-conditioning and appliances. The Energy Information Administration (EIA) reported that residential energy use accounted for nearly 22% of the total national energy use in 2003. (See Figure 1.9 in Chapter 1.) For household energy consumption in 2001 (the most recent data compiled by the EIA), space heating used 47% of the total energy consumed, down from 51% in 1997; appliances 30%, up from 27%; water heating 17%, down from 19%; and air conditioners 6%, up from 4%.

The percentages of households with electric appliances has increased steadily over the last couple of decades. (See Figure 9.7.) By 2001, 99% of American homes had color televisions, 86% had microwave ovens, 79% had clothes washers, and 56% had personal computers.

In 1987 Congress passed the National Appliance Energy Conservation Act (NAECA; PL 100-12), which gave the Department of Energy the authority to formulate minimum efficiency requirements for thirteen classes of consumer products. It could also revise and update those standards as technologies and economic conditions

FIGURE 9.7

changed. Table 9.8 shows the products affected and the years in which appliance efficiency standards were established or revised for each, as well as the future effective dates of standards.

Energy efficiency has increased for all major household appliances but most dramatically for refrigerators and freezers. Since 1972 new refrigerators and freezers have more than tripled in energy efficiency because of better insulation, motors, compressors, and accessories such as automatic defrost ("Good Stuff? A Behind-the-Scenes Guide to the Things We Buy: Appliances," WorldWatch Institute, http://www.worldwatch.org/pubs/goodstuff/appliances/this.href [accessed January 14, 2005]). These improvements have been accomplished at relatively low cost to manufacturers. In addition, efficiency labels for consumers are now required, which makes purchasing efficient models easier.

According the U.S. Department of Energy, by the early 2000s, air conditioners and heat pumps, another major group of appliances, had shown a 30–50% improvement in energy efficiency since the mid-1970s. Although this improvement in energy efficiency was less than the improvements in refrigerators and freezers, it is significant because these appliances are large energy users.

Water heaters and furnaces improved efficiency between 5% and 20% from the mid-1970s to the early 2000s. However, the technological improvements in these appliances are relatively costly compared to the overall price of the product. This means that the more energy-conserving models have a higher retail price, which discourages many consumers from purchasing efficient models, even though the more efficient models may save money in the long run. In addition, many purchases of water heaters and furnaces are made by builders, who have little incentive to pay more for the most efficient models, or by homeowners in emergency situations, when fast availability and installation seem much more important than energy efficiency.

Nonetheless, consumers are sometimes willing to purchase more expensive, energy-efficient models of air conditioners, refrigerators, and lights if the devices can save them enough money in the long run on their electricity bills to offset the higher purchase costs. According to a U.S. General Accounting Office study (Energy Conservation: Efforts Promoting More Efficient Use, Washington, DC, 1992), consumers will purchase such devices if the "payback period" is two years or less.

In addition to concerns about efficiency, appliance makers, especially those who make refrigerators and airconditioning systems, are striving to develop alternative cooling techniques as substitutes for chlorofluorocarbons (CFCs), which are ozone-damaging chemicals that can no longer be legally sold in the United States. Current technology

TABLE 9.8

Effective dates of appliance efficiency standards, 1988–2007
Product	1988	1990	1992	1993	1994	1995	2000	2001	2003	2004	2005	2006	2007
SOURCE: "Table 2. Effective Dates of Appliance Efficiency Standards, 1988–2007," in Annual Energy Outlook 2002, U.S. Department of Energy, Energy Information Administration, Office of Integrated Analysis and Forecasting, December 2001, http://tonto.eia.doe.gov/FTPROOT/forecasting/0383(2002).pdf (accessed November 22, 2004)
Clothes dryers	X				X
Clothes washers	X				X					X			X
Dishwashers	X				X
Refrigerators and freezers		X		X				X
Kitchen ranges and ovens		X
Room air conditioners		X					X
Direct heating equipment		X
Fluorescent lamp ballasts		X									X
Water heaters		X								X
Pool heaters		X
Central air conditioners and heat pumps			X									X
Furnaces
Central (>45,000 Btu per hour)			X
Small (<45,000 Btu per hour)			X
Mobile home		X
Boilers			X
Fluorescent lamps, 8 foot					X
Fluorescent lamps, 2 and 4 foot (U tube)						X
Commercial water-cooled air conditioners										X
Commercial natural gas furnaces										X
Commercial natural gas water heaters										X

is temporarily substituting CFCs with somewhat less dangerous HCFCs (hydrochlorofluorocarbons). In Europe, refrigeration units using other substances, such as propane "greenfreeze" technology, are rapidly replacing HCFCs.

Lawn and Garden Equipment

In 1994 the Environmental Protection Agency (EPA) reported that as much as 10% of the nation's air pollution was generated by gasoline-powered lawn and garden equipment, including lawn mowers, chain saws, and golf carts. Former EPA administrator Carol Browner estimated that Americans use eighty-nine million pieces of such equipment, with lawn mowers alone accounting for 5% of the nation's air pollution.

Under Browner, the agency established engine label and warranty requirements, exhaust emissions standards, and test procedures, requiring that engine makers meet the new requirements by 1996. Effective that year, new products offered for sale were equipped with improved carburetion systems, and additional standards were scheduled for subsequent years. Agency officials reported in 2000 that the new regulations had reduced smog-forming hydrocarbon emissions by 32% and that additional standards to be phased in between 2001 and 2007 were projected to reduce hydrocarbon emissions an additional 10%.