Consumer Guide to Home Energy Savings|
How do I get started improving my home's energy efficiency?
Take a look at ACEEE's home energy Checklist
for Action. The simple checklist will give you an idea of the
things you can do right away and over the course of the coming weeks,
months, and year to increase the energy efficiency of your home.
Heating and Cooling
How is the energy efficiency of heating and cooling equipment rated?
The type of rating used depends on the type of equipment. The efficiency of
a gas or oil furnace
or boiler is reported as the annual fuel utilization efficiency,
or AFUE. This is a measure of the system's efficiency that accounts
for start-up and cool-down and other operating losses that occur
under real operating conditions. The efficiency of an electric
heat pump when it is operating in heating mode is given as the
heating season performance factor (HSPF). This is a ratio of the
estimated seasonal heating output in BTU divided by the seasonal
power input in watt-hours.
The cooling efficiency of a central air
conditioner or heat pump is rated according to the seasonal
energy efficiency ratio (SEER), which is the seasonal cooling output
in BTU divided by the seasonal energy input in watt-hours for an
average U.S. climate. By considering energy input and cooling output
over the entire cooling season, the SEER method attempts to account
for system performance throughout the warm months. The efficiency
of room air conditioners is measured by the energy efficiency ratio
(EER), which is the cooling output in BTU divided by the power input
What steps should I take to get an energy-efficient heating or cooling system installed in my home?
First and foremost, find a qualified contractor. Choosing a good contractor to install
a new furnace or central air conditioner can be as important as
the equipment you choose because proper installation and maintenance
is needed for the equipment to operate safely, reliably, and at
maximum efficiency. For more information, see ACEEE's
tips on picking the right contractor, read the advice from ENERGY
STAR, and download their useful HVAC
Next, talk to your contractor about installing a high efficiency system. See
ACEEE's recommendations for purchasing a new furnace
or boiler, central air conditioner,
or heat pump.
When should I replace my natural gas furnace?
If your furnace has a pilot light, it was installed prior to 1992 and its annual
efficiency is probably less than 65%, perhaps much less. Compare
that to the least efficient furnaces available today which
are rated at 80% (or 80 AFUE) and you can see that your old furnace
is a prime candidate for replacement. In cold climates, a condensing
furnace with an efficiency rating of at least 90 AFUE will generally
be a very good value. Don't forget to consider the furnace electricity
consumption as well - some furnaces consume more electricity
than a refrigerator just to power the furnace fan. Check out ACEEE's
recommendations for purchasing a new furnace
for more information and tips.
How much money can I expect to save by replacing my old furnace or air conditioner?
That depends on the price of fuel or electricity. You can compare the cost of
running a new furnace or air conditioner to the cost of running
your existing unit using the ENERGY STAR savings calculator. Just
enter the price you pay for fuel or electricity from your utility
bill. And remember, energy-efficient equipment is a great hedge
against rising utility bills - if the price of natural gas or
electricity goes up, you'll see a much smaller increase, if any,
in your heating and cooling bills. (The ENERGY STAR savings calculators
are downloadable Excel files. Click to download the calculator you
would like to use: central
air conditioner, heat
I would like to get rid of the window units that air condition my home. What are my options?
There are three options, each with their own costs and benefits:
- Conventional ducted systems can be very efficient and may be the least
expensive depending on the layout of your house. With this type
of system, conventional ducts would be installed to move cooled
air throughout your house. A typical two-story house would get
two separate systems: one in the basement with registers in the
floor to cool the first level of the house; and a second system
in the attic with ceiling registers to serve the second floor.
- Small diameter high velocity systems are specialty products that
use insulated flex ductwork small enough to run through existing
walls. Installation of these systems does not require new duct
chases, but the trade-off for the space savings is lower energy
efficiency. Hire an experienced contractor capable of carefully
engineering the system to keep operating noise to a reasonable
level. Manufacturers include SpacePak
- Ductless systems are the easiest retrofit option for replacing window-mounted
room air conditioners. These systems consist of an outdoor unit
(the condenser) and one or more indoor units with an evaporator
to cool air and a fan to move the air around the space. The small
indoor units are typically mounted through an exterior wall. Ductless
systems are quieter and more efficient than room air conditioners
and have better controls. Like room air conditioners, each indoor
unit can only cool a single room or area of the house. These systems
are also much easier to zone than central ducted systems, so you
can save energy and money by only conditioning the rooms that
are in use.
Should I install a programmable thermostat? Does it make sense to program
several different set points throughout the day?
A programmable thermostat is a convenience that can improve your comfort and reduce
your heating and cooling bills IF it is programmed properly. When
programming your thermostat, remember that the smaller the difference
between the indoor and outdoor temperatures, the less energy (and
money) needed for heating and cooling. By setting back the temperature
(reducing indoor temperature in winter or increasing it in summer)
during the time when you are normally away or asleep, you will save
money. And, contrary to some common myths, it won't take more energy
to bring your home back to the desired temperature than it would
to leave it at your optimum temperature all day. We estimate heating
and cooling savings of 5% when the thermostat is properly programmed.
If you have a heat pump, be aware that you need a special "adaptive"
thermostat that will bring the temperature up from the setback point
in winter without calling for the inefficient "emergency"
electric resistance heat.
According to my contractor, I need to replace the outdoor unit (the condenser)
of my central air conditioner. Should I replace it alone or
should I replace the indoor portion (the evaporator) at the
Two-part air conditioners and heat pumps, also called split-systems, should be
selected and installed as a matched set to maximize efficiency,
comfort, reliability, and long life. In recent years, improvements
to both condensers and evaporators have yielded big gains in efficiency
and performance that can only be captured if both parts of the system
are properly matched. Keep in mind, when if comes to efficient operation
and long life, careful installation is as important as specifying
the right equipment. See ACEEE's recommendations for more on selecting
an air conditioner and finding
a qualified contractor.
Why doesn't ACEEE list the most efficient electric water heaters on your Web site?
As a result of the revised minimum efficiency standard for water heaters that
took effect in January 2004, there is little difference between
the most and least efficient units available today. We no longer
list these products, because there is very little energy savings
to be gained by choosing the highest rated products. If you rely
on electricity for water heating, keep a lookout for greater availability
of heat pump water heaters. These units use about half as much electricity
as conventional electric resistance water heaters. You may also
be interested in a solar water heater or pre-heater. Learn more
about this technology from the Department
of Energy and the Florida
Solar Energy Center.
Should I replace my old water heater with one of the new tankless water
heaters (also called instantaneous or demand water heaters)?
Tankless water heaters do not contain a storage tank like conventional water heaters.
A gas burner or electric element heats water only when there is
a demand for hot water. Hot water never runs out, but the flow rate
(gallons of hot water per minute) may be limited. By eliminating
standby losses from the tank, energy consumption can be reduced
by 10-15%. Before rushing out to buy a demand water heater, be aware
that they are not appropriate for every situation. Here are some
of the factors to consider:
- Do you use hot water efficiently? Have you installed modern, low-flow faucets
and showerheads? Tankless water heaters perform much better when
coupled with efficient uses.
your water distribution system. If the hot water uses in your
home are relatively close together, with short hot water lines
between them, a tankless system may work for you. In many U.S.
homes, water uses are widely spaced at opposite ends of the house.
If this is the case in your home, a tankless system may not meet
- If you have
installed high efficiency fixtures and your water lines are not
too long, consult an experienced contractor to find out if your
gas supply is adequate and proper venting is feasible.
residential wiring generally will not support a tankless electric
water heater with large enough capacity to serve multiple uses.
If you rely on electricity to heat your water, a tankless system
is unlikely to meet your needs. At most, an electric unit may
be appropriate for small applications, such as a remote bathroom
without a bath tub.
To learn more
about tankless water heaters, visit these manufacturers' sites:
Takagi. The Oregon Department
of Energy maintains a list
of the most efficient gas-fired tankless water heaters which
qualify for state tax credits.
How can I find information about clothes dryer efficiency?
There is no requirement to display the EneryGuide label on clothes dryers, so
it is not easy to compare the energy use of various dryer models.
In terms of energy use, gas dryers are generally less expensive
to operate than electric models. Within the respective gas and electric
dryer categories, however, the energy use of dryers currently on
the market does not vary widely. Other than fuel type, the major
energy consideration is whether the dryer uses controls to sense
dryness and turn the dryer off automatically. The best dryers have
moisture sensors in the drum for sensing dryness. Another consideration
is how dry the clothes are when they are put into the dryer. Today's
resource-efficient clothes washers use higher spin speeds to remove
more water from clothes while they are still in the washer. Consider
upgrading to a high-efficiency clothes washer to maximize energy
savings throughout the laundry cycle.
Do the clothes washer and dishwasher ratings published by ACEEE
and on the EnergyGuide label include the energy used to heat
water as well as the electricity used by the clothes washer
Yes. The top-rated clothes washer and dishwasher models cost less than $30 a year to
operate, including both the energy used to heat the water and the
electricity used directly by the appliance. Efficient new clothes
washers and dishwashers use much less water than older models. Online,
ACEEE lists the most efficient clothes
washers and dishwashers.
All models included in ACEEE's list exceed the ENERGY STAR requirements.
You can also download the full list of ENERGY
STAR qualified models.
How can I find energy-efficient replacements for my halogen torchieres lamps that will provide equivalent brightness and light quality?
Halogen torchieres present a fire hazard because they generate extreme heat. That heat is a sign of wasted energy. ENERGY STAR qualified torchieres use only a fraction of the energy required by halogen torchieres. The extra cost of the ENERGY STAR model can be recouped by energy savings in as little as one or two years. Because these torchieres are optimized for compact fluorescent lamps (CFLs), they can match the light quality and brightness of halogen models. ENERGY STAR maintains a list of qualified fixtures on their Web site (Note: this is a searchable Excel file).