Overview: Costs and savings
Staying cool is expensive. In a hot climate like Texas, the average family spends
about $600 a year on cooling. In the Midwest, it’s about $300. But costs vary a lot
within regions and even within a single neighborhood. Your home may cost $700
to keep cool while a similar home next door costs half that. This article will help
you make your home the low-cost energy leader on the block. Our focus is on cutting
cooling costs, but many of these tips will save you money on your heating too.
We include upfront costs and payback for each of our tips, but the actual figures
depend on your individual house, region, climate, living habits and electric rates.
Tip 1: Replace your old air conditioner
Replacing a 10-year-old window or central AC unit with an
Energy Star model can cut your cooling costs by 30 to 50
percent and save you enough over the new unit’s lifetime
to offset its purchase price. This is especially
true if you live in a hot, humid climate.
Central AC units are rated for efficiency
according to their Seasonal Energy-
Efficiency Ratio (SEER). Window
units are rated according to their
Energy-Efficiency Ratio (EER). The
SEER/EER rating is listed on the Energy
Guide label (below). The higher the
number, the more efficient the unit. If
you double your SEER (or EER), you can
cut your AC operating costs in half. To
find the rating on an older unit, check the
data label or plug the model number into the
online CEE-ARI database at < href="http://www.energystar.gov">energystar.gov on
the Central Air Conditioners page. New units
are required by law to have a SEER of at least
13 and an EER of 8. Central AC units manufactured
from 1992 through 2005 have a SEER of
about a 10, and older models are at 6 or 7.
COST: Window units range from $250 for 6,000
BTUs to $750 for 24,000 BTUs. Replacing an old central-air system typically costs about $3,000, but it can
run as high as $10,000.
PAYBACK: The older your system and the
more you use it, the larger your energy savings
will be with a new unit. For example, replacing an ancient
SEER 7 unit with a SEER 14.5 unit that
costs $3,000 will save you about $700 a
year and pay for itself in five years.
Calculate your payback with the AC savings
calculator at energystar.gov.
Online savings calculator
AC Shopping Tips
- Buy an Energy Star–rated central
AC unit with a SEER of 14 or higher
(especially if you use your AC a lot).
- Buy the right-size central AC unit by
making sure your contractor performs
a thorough cooling load
analysis on your home. Too many
contractors simply choose a unit
that’s the same size as the old one.
In many cases, the old one is oversized,
so it wastes electricity.
- Replace the entire unit, not just the
outside condenser. If you don’t
replace the inside coil and/or
blower fan, you won’t get the rated
- Buy a unit with eco-friendly coolant
(R41A “Puron”) since R22 (Freon)
will be phased out of production in
2010. If you get stuck with an old
Freon unit, recharging the system
will be very expensive (not to mention
- Use the Energy Star savings calculator
at energystar.gov to figure out
whether it makes financial sense to
replace your AC, and get a list of
the most energy-efficient AC units.
- Check for local, state and federal
rebates on higher efficiency units at
- If you live in the Southeastern
United States, consider a heat
pump, which moves air more efficiently
than a conventional AC unit
in areas with high humidity. If you
live in the Southwest, consider an
evaporative “swamp” cooler, which
uses 75 percent less energy than
conventional AC and costs about
half as much to install. For more information, go to energystar.gov.
DIY Success Story
“My neighbor complained for years
that my 22-year-old AC unit was too
noisy. To keep the peace, I decided to
replace it. The old unit turned out to be
a SEER 6. The new unit is a SEER 14
and very quiet. My neighbor is now
happy and so am I—my summer electric
bills are half of what I was spending
with the old unit.”
Tip 2: Switch to CFLs
You already know that compact fluorescent
Light bulbs cut lighting
costs, but they cut cooling costs
too. That’s because, unlike incandescents,
they give off very little
heat. Ninety percent of the electricity
used by an incandescent
bulb is converted to heat rather
than light. That extra heat means
extra cooling expenses.
Online savings calculator
COST: $3 per bulb.
PAYBACK: Less than a year.
Tip 3: Install a programmable thermostat
This is another easy upgrade
that pays back quickly. Setting
your cooling system four to six
degrees warmer when you’re
away at work or on vacation
and automatically lowering it to
78 degrees when you’re home
can cut 5 to 20 percent off your
energy bill. This simple DIY project
takes less than an hour.
COST: $50 to $150.
PAYBACK: About a year if you use it for both
heating and cooling.
Tip 4: Clean or change AC filters monthly
Dirty air filters are the No. 1
cause of air conditioning breakdowns
and they cost about 7 percent
more in energy costs (or
about $45 a year) in hot climates.
Change central AC furnace filters
monthly during the summer. Most window
units have a removable filter behind the air inlet grille that you can take out
and rinse monthly.
Tip 5: Fix leaks in AC ducting
If your home was built in the past 10
years or so, it probably has well-sealed
ductwork. But if you live in an older
home, 10 to 40 percent of your cooling
dollars is lost through gaps in the duct
joints. This cool air is wasted when the
ducts run through an attic, crawl space
or basement. This can be a tough DIY
project to do effectively since it takes a
professional to test for leaks before and
after the repairs. It you’re game for sealing
the ducts yourself, examine your
ductwork for cracks, splits or bad connections
and feel for escaping air when
your system is on. After you seal the
leaks, keep the ducts cool by insulating
them with R-6 or higher fiberglass duct
wrap if they run through a hot attic.
COST: $300 to $1,000 for a professional
to test and seal your heating and cooling
ducts. DIY duct sealing costs $20 for a 60-yd. roll of aluminum tape and $5 for an 11-oz. tube of sealant.
PAYBACK: Two to four years for professional
duct sealing and less than a year for
Tip 6: Block out sun with window shades
Roughly 30 percent of unwanted heat
comes through your windows. Putting
shades, insulating curtains or tinted
window film on south- and west-facing
windows can save you up to
7 percent, or $45, annually on
cooling costs. The combination of
shades and trees (see Tip 7) can
lower indoor temps by 20 degrees
on a hot day. Insulating curtains
will save even more on both heating
and cooling costs.
COST: Shades, $10 per window; low-E films,
$5 per window; insulating curtains, $30 to $150
PAYBACK: One to four years depending on initial costs and where you live.
Tip 7: Keep cool with shade
Cut AC costs through your own sweat equity
by shading your house with trees, trellises
and vines. Shading blocks direct sunlight
through the roof and windows, which is
responsible for about half of the heat gain in
your home. Carefully positioned trees and
horizontal trellises on the east and west sides
can save up to 30 percent of a household’s
energy consumption for heating and cooling.
For an average household, that’s $100 to
$250 in energy costs annually.
COST: Three 6-ft. trees, $900; DIY trellis, $50
(for a bare-bones version) up to $500 (for the
deluxe model); vines for trellis, $50.
PAYBACK: On average, a well-designed landscape
provides enough energy savings (heating
and cooling) to return your initial investment in six
to eight years.
Tip 8: Check your AC system’s efficiency
To determine whether your air conditioner needs a tune-up, perform
this easy test when your AC unit has been running for at least 15 minutes
and the outdoor temp is above 80 degrees F. With a clean air filter
in place, set a thermometer on the supply register that’s closest to the
inside cooling equipment. Keep it there for five minutes and note the
temperature. Do the same thing at the return vent. The air coming out
should be 14 to 20 degrees cooler than the air going in. An air conditioner
that’s not cooling to those levels could be low on refrigerant or have leaks. A
unit cooling more than 20 degrees could have a severe blockage.
Tip 9: Use fans and raise your thermostat
Ceiling fans can save you money by
keeping you comfortable at higher thermostat
settings. Each degree higher
than 78 degrees will save you 5 to 10
percent on air conditioning costs. The
moving air from a ceiling fan increases
the amount of evaporation from your
skin and helps cool you off.
Here are step-by-step instructions for installing a ceiling fan.
COST: Ranges from $50 to $1,000. Energy
Star–rated fans are about 10 percent more
efficient than standard ceiling fans and are
usually in the $150 and above range.
PAYBACK: Depends on how high you set
your thermostat and the cost of the fan.
Could be as fast as three years or as long as
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Tip 10: Tune and clean your AC regularly
A poorly maintained air conditioner uses 10 to 30 percent
more energy and has a shorter life. Central AC compressors
last on average about 10 to 12 years. Proper maintenance
can extend that to 20 years. It’s important to have a
professional tune, clean and check controls and refrigerant
levels on your central AC system every two to three
years. If your refrigerant needs recharging, this correction
can improve efficiency by 20 percent. It’s also important
to perform DIY maintenance each year. Several contractors
told us that 90 percent of air-conditioner failures are
caused by a lack of maintenance.
COST: Professionally cleaning and servicing a central air conditioner
costs $100 to $250.
PAYBACK: This depends on the age of the unit and how dirty it
is. If you haven’t had your AC unit serviced in several years, having
a professional do a thorough tune-up could pay for itself in less
than a year and extend the life of your unit.