Business
Bracing for Winter - Part six of a series: The thermostat
If you turn down the heat when you're sleeping, you'll use less fuel
09:30 AM EST on Monday, November 14, 2005
Part six of a series
Turn the heat down before you leave the house.
It's an old adage many of us try to follow. But does it really cut
heating costs?
Energy experts say yes. Turning back a thermostat is an effective way of
trimming heating bills by 10 percent a year, or more.
But doing so is easy to forget. And it's unpleasant to come home to a
cold house.
Both of those issues are easily fixed by installing a programmable
thermostat.
This device is essentially a fancy switch that turns the heat on and
off, depending on the inside room temperature -- just as the old manual
type does.
But a programmable thermostat can also be instructed to automatically
turn down the heat at a specific time, and turn it up again later in the
day.
Programmable thermostats can be used for most heating systems, but are
not recommended for heat pumps.
Prices run from $40 on up, and the cost of the unit can be recouped in
lower energy bills in just a few months.
"We really encourage people to get them," said Christina Kielich, a
spokeswoman for the U.S. Department of Energy. "It's a really small
investment for a big return."
For each degree a thermostat is turned down for an eight-hour period,
heating costs are trimmed by 1 percent, according to the Energy
Efficiency and Renewable Energy division of the energy department.
The agency has a calculator on its Web site that computes the savings
and the pay-back period for various climates. It also lets you plug in
specific rates for energy in your area.
For example, a Providence household that buys three programmable
thermostats at $50 each will recoup that money in about seven months. A
residential natural-gas heating customer who turns back the thermostat
to 62 degrees at night from 70 degrees during the day would save $235 a
year, according to the calculator. The savings with an oil boiler would
be $248 a year. (See the link below to try it yourself.)
A programmable thermostat is fairly simple to install, involving little
more than a screwdriver and some patience.
Journal photo illustration / Kris Craig
Programming them is simple, too. In general, you tell the thermostat
what temperature you want the house to be at a specific time. The
devices usually allow four temperature changes during a day.
For example, you might want the temperature to be 68 degrees at 7 a.m.,
when you wake up. At 8 a.m., when you leave for work, you may want the
temperature to drop to 60 degrees. The thermostat can turn the
temperature back up to 68 degrees when you arrive home at 6 p.m. And it
can turn it back down to 62 degrees at 10 p.m., when you go to bed.
Some thermostats have the ability to figure out how long it takes your
heating system to get up to temperature. That way, it knows precisely
when to turn on the furnace or boiler so it is at the right temperature
at the programmed time.
Some units keep a log of how often the heat was turned on during the
day, during the week and during the whole season.
How low should you turn back the thermostat?
Kielich, the Energy Department spokeswoman, said to turn it down as low
as you are comfortable with, but not below 55 degrees. Below that, you
run the risk of freezing pipes.
A common misconception about turning down a thermostat is that the
heating system works harder than normal to bring the temperature up,
resulting in no savings.
The Energy Department says that theory has been dispelled by years of
research.
The amount of fuel needed to reheat the house is about equal to the fuel
saved as the building drops to the lower temperature, according to the
Energy Department.
So, the longer your house remains at the lower temperature, the more
energy you save.
-- Timothy C. Barmann covers energy issues, utilities and technology. He
can be reached at tbarmann@projo.com
Programmable-thermostat savings calculator
The calculator is a downloadable Excel spreadsheet
Use these Rhode Island energy rates: electricity, $0.141 per
kilowatt-hour; gas, $1.74 per therm; and heating oil, $2.459 per gallon.
More details about programmable thermostats are available at:
http://www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/mytopic=12720
