Unit 1 Housing—Human Factors and Infl uences
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to power a house for several days, but persistent
overcast weather can deplete it. Deluxe systems can
match the reliability of power supplied by utility
companies, but they are expensive. As the cost of
solar electric systems declines, environmentally
conscious home owners will likely invest in this
technology.
Some solar energy heating systems supply more
energy than a home needs. Home owners can sell the
excess to a utility company or store it in the lines until
needed by the producer. Net metering programs also
provide consumer investment in renewable energy
generation. The plan allows customers to use their own
generation to balance their consumption. The electric
meters turn backward when they generate electricity in
excess of their demand (Figure 4.6).
Geothermal and Wind Energy
Geothermal energy—energy that comes from
the earth’s core—and wind energy are the primary
sources of energy the United States uses in power
plants to produce electricity. Although most homes
still use traditional furnaces and air conditioners,
geothermal heat pumps are becoming more popular.
In recent years, the U.S. Department of Energy (DOE)
and the Environmental Protection Agency (EPA)
have partnered with industry to promote the use of
geothermal heat pumps.
Geothermal heat pumps use the earth’s
constant temperatures to heat and cool buildings.
While temperatures above ground are unstable,
temperatures in the upper 10 feet of the earth’s
surface remain constant. The soil temperatures are
usually warmer than the air in winter and cooler
than the air in summer. The heat pumps transfer
heat from the ground (or water) into buildings in
winter and reverse the process in the summer.
Geothermal energy has advantages and
disadvantages. One advantage is its low cost in
comparison to other fuels. It also is a source of
heat that does not emit harmful pollutants into the
environment. A third advantage is that geothermal
energy is a renewable resource.
pics721/Shutterstock.com
Figure 4.4 A sunroom is a beautiful and calming space;
however, if the orientation is not correct, it can become
hot like a greenhouse and be unusable space.
jessicakirsh/Shutterstock.com
Figure 4.5 This house has solar panels on the roof to
take advantage of active solar heating.
Goodheart-Willcox Publisher
Figure 4.6 In a photovoltaic system, silicon chips are
joined with electrical wires to form solar cell arrays. The
arrays collect different amounts of solar energy, depending
on the season, time of day, and degree of cloudiness.
AC
electricity
to house
Incoming
electricity
meter
Outgoing
electricity
meter
Solar cell array