How Energy-Efficient Is Your System?
The air conditioning and heating industry uses a measure known as "SEER"
to rate the energy efficiency of air conditioners ("SEER" is an acronym for
"Seasonal Energy Efficiency Rating"). In simple terms, the higher the SEER
rating, the greater the amount of cooling that the system provides for each
unit of electricity used.
Because of advances in technology and design, newer systems have a SEER
rating as high as 17 or 19. In fact, Federal Government regulation on 1/23/06
will require that new air conditioning units have a SEER of at least 13. By
comparison, units that are 8 or more years old probably had a SEER rating of
10 or less when they were installed. Depending on the level of maintenance
given the unit, that rating may now be much lower.
What that means to you as a home owner?
Simply that a new unit could save you anywhere from 16 to 40% of your
cooling bills. For example, while a new unit could produce 15 BTU's of cooling
for one Watt-hour, an older unit that has been poorly maintained may only be
producing 7 BTU's of cooling.
Consider the following example (you will be able to modify it to analyze the
energy efficiency of your system):
The Basic Formula for Annual Cooling Costs
Unit Capacity in BTU's/hr
X Annual Cooling Hours
____________________
SEER No. |
X |
Cost/Kilowatt-hour
_________________
1000 watts/Kilowatt |
= |
Approximate Annual
Cooling Cost |
Hours of Cooling Per Year
In the Brazos County area, the cooling season typically requires approximately
2,200 hours of system run time!
Annual Cooling Cost Calculation
Assuming a Kilowatt-hour cost of $.07 (where a Kilowatt is a thousand watts),
the projected cost of cooling a home with an older air conditioner with a 7.0 SEER
rating would be as follows, when a 60,000 BTUH (5 ton) cooling load is assumed:
60,000 BTU's/hr
X 2,200 hours
________________________
7.0 SEER |
X |
$.07/Kilowatt-hour
_________________
1000 watts/Kilowatt |
= |
$1,320 Expected
Annual
Cooling
Cost |
With the same assumptions, a newer air conditioning unit with a SEER
number of 15.0 would be expected to cool the house for a much lower cost:
60,000 BTU's/hr
X 2,200 hours
________________________
15.0 SEER |
X |
$.07/Kilowatt-hour
_________________
1000 watts/Kilowatt |
= |
$616 Expected
Annual
Cooling
Cost |
Savings
In the example above, a new, high efficiency air conditioner produced
annual savings of $704 - and that is without considering other energy savings
devices like programmable thermostats.
If you would like more information about how having a more energy-efficient
air conditioner may benefit you personally, it will require a more detailed
look at your specific situation.
If your electric bill is more than double in the summer than in the winter,
you should consider having your present air conditioner unit checked out. (This
assumes that the principal difference in electricity usage is due to air
conditioning load. If there is some other explanation for the increase in energy
costs, e.g., the energy costs of operating a pool, you may need to do a further
analysis.)
These examples are by way of illustration only. Actual results will vary and
the savings attained may not be as large as in the example.
Note that there are a number of factors that may affect the number of BTU's
required to heat or cool your home, such as level of insualtion in the home,
shading, number and type of windows, thermostat settings, number of floors,
traffic in and out of the home, and other factors. However, an air conditioner
with a higher SEER rating will always require less energy to cool the home than
a unit with a lower rating. You may obtain further energy and utility savings by
adjusting some of those other factors, e.g., by using a time-controlled thermostat
to reduce the cooling requirements when the home is unoccupied, using a
heat pump, etc.
Frequently Asked Questions
Q: What is a "ton" of air conditioning?
A: In air conditioning, a ton equates to 12,000 British
Thermal Units per Hour (BTUH). For instance, a 3-ton air conditioning unit
can remove a combined sensible and latent (humidity) load of 36,000 BTUH
per hour (3 x 12,000).
Q: Will a 12 SEER unit cool better than a 10 SEER unit?
A: The capacity or size of an air conditioner should not
be confused with the efficiency rating. New units of like capacity cool
equally as well regardless of efficiency rating. However, the unit with the
higher efficiency rating uses less electricity.
Q: My air conditioning unit does not performed as well
as it used to. Do I need a bigger one?
A: Air conditioning units tend to lose their efficiency
with time, so a newer unit will provide the full capacity for which it was
designed while an older unit doesn't. Upsizing is rarely needed, however,
unless other changes have been implemented in the home. In fact, downsizing
sometimes is recommended if factors such as additional insulation or storm
windows have been added. A professional can determine the requirements for
your home with an on-site visit.
Q: How do I know how much air conditioning I need?
A: Be careful using any rule of thumb method to
determine the capacity requirement for your home. Under-sized equipment
obviously will not keep your home comfortable during peak cooling demand
times, and over-sized equipment could be more expensive to operate and
cause problems of high humidity. A professional dealer or contractor has
the knowledge to properly calculate the size unit needed for your home,
and should be consulted.
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Contact Us
Climate Masters of BCS
(979) 775-6572
TACBLD010069E
Email us at: info@cmastersofbcs.com
