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The American Energy Consumer
Table 3-22.Trend in Energy Use of Water
Heaters by Energy Source, Selected Years, 1950-1971
| Energy source and
year |
Standard water
heater |
| Electric |
Btu's (millions) |
| 1950 |
40 |
| 1959 |
43 |
| 1969 |
46 |
| Natural gas |
|
| 1960 |
24 |
| 1966 |
27 |
| 1971 |
32 |
| Source: Prepared by
the Washington Center for Metropolitan Studies from unpublished
materials from the American Gas Association, Arlington, Virginia,
and the Edison Electrical Institute, New
York. |
Electricity
is the most fuel intensive energy source, and the amount of energy
needed to run electric water heaters has been increasing. In 1959
the average electric water heater used about 43 million Btu's
annually. By 1969 its energy use had increased to 46 million Btu's,
but a new, more energy intensive model was on the market as
well—a quick-recovery electric water heater that uses 52
million Btu's annually. Energy used in natural gas water heaters
has also increased, from an average of 24 million Btu's in 1960 to
32 million Btu's in 1971 (Table 3-22). Hot water is used for
washing—dishes, clothes, and people. The amount used varies
with the number of people in the household and the use of
appliances that consume large amounts of hot water such as
automatic dishwashers and clothes washers.
APPLIANCES
Cooking and
refrigerating appliances account for about 6 percent of all
personal energy consumption. Other appliances and lighting use an
additional 9 percent (see Table 3-1 above).
Energy
Use of Appliances
How much
energy an appliance uses in a given year depends on how much energy
it takes to run the appliance per second or per hour, as well as
how much the appliance is used. For example, the average wattage
(energy per second) of a microwave oven is 1,450. This is over four
times the wattage of a 12 cubic foot frost-free refrigerator. Yet
over a year, the oven uses less than one-fifth as much energy as
the refrigerator, because the refrigerator is
plugged