You can easily save energy in the winter
by setting the thermostat to 68°F (20°C) when you're at home
and awake, and lowering it when you're asleep or away.
This strategy is effective and inexpensive if you are willing
to adjust the thermostat by hand and wake up in a chilly house.
In the summer, you can follow the same strategy with central
air conditioning, too, by keeping your house warmer than normal
when you are away, and lowering the thermostat setting to
78°F (26°C) only when you are at home and need cooling.
A common misconception associated with thermostats is that
a furnace works harder than normal to warm the space back
to a comfortable temperature after the thermostat has been
set back, resulting in little or no savings. This misconception
has been dispelled by years of research and numerous studies.
The fuel required to reheat a building to a comfortable temperature
is roughly equal to the fuel saved as the building drops to
the lower temperature. You save fuel between the time that
the temperature stabilizes at the lower level and the next
time heat is needed. So, the longer your house remains at
the lower temperature, the more energy you save.
Another misconception is that the higher you raise a thermostat,
the more heat the furnace will put out, or that the house
will warm up faster if the thermostat is raised higher. Furnaces
put out the same amount of heat no matter how high the thermostat
is set-the variable is how long it must stay on to reach the
In the winter, significant savings can be obtained by manually
or automatically reducing your thermostat's temperature setting
for as little as four hours per day. These savings can be
attributed to a building's heat loss in the winter, which
depends greatly on the difference between the inside and outside
temperatures. For example, if you set the temperature back
on your thermostat for an entire night, your energy savings
will be substantial. By turning your thermostat back 10° to
15° for 8 hours, you can save about 5% to 15% a year on your
heating bill-a savings of as much as 1% for each degree if
the setback period is eight hours long. The percentage of
savings from setback is greater for buildings in milder climates
than for those in more severe climates. In the summer, you
can achieve similar savings by keeping the indoor temperature
a bit higher when you're away than you do when you're at home.
To maximize your energy savings without sacrificing comfort,
you can install an automatic setback or programmable thermostat.
They adjust the temperature setting for you. While you might
forget to turn down the heat before you leave for work in
the morning, a programmable thermostat won't! By maintaining
the highest or lowest required temperatures for four or five
hours a day instead of 24 hours, a programmable thermostat
can pay for itself in energy saved within four years.