AIR CONDITIONERS:
WHAT DO I NEED?

GOAL:
The student will be familiar with the processes of assessing air conditioning needs and choosing the proper air conditioning system for a particular house.

OBJECTIVES:
The student will be able to:
1. State the need for energy efficient air conditioning in Louisiana.

2. Explain how to choose the right type and size of air conditioner to fit the homeowner's needs.

3. Explain the efficiency rating system used for air conditioners.

4. List other recommendations that help reduce energy used for cooling.

LESSON / INFORMATION:
Energy used in heating and cooling accounts for approximately 50% of the average homeowner's energy budget. In Louisiana, where cooling and dehumidification are the main concerns, reducing energy use and energy waste associated with home cooling can save energy dollars.

Air conditioners really do condition the air. Not only do these appliances cool air, but they also remove dust and dirt as well as lower humidity levels. Since these appliances use so much energy, it is imperative that careful consideration be given to the type and size of the unit selected.
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Consumers can choose between room air conditioners or central air conditioners. Room units cost less but can only cool the immediate area. Central air conditioning systems usually provide greater comfort but also cost more.

It is more difficult and not always cost effective to try to incorporate a central air conditioning system into an existing home that does not have the necessary ductwork to circulate the air.

Activity 1:
Take a survey of 10 family members or friends.

How many use room air conditioners?_____ How many units are needed per house?_____ How many use central air?_____ How many have no air conditioning?_____

After the homeowner has chosen the type of air conditioner to install, the next major concern is what size system is needed.

The energy wise shopper should know that choosing a system that is either too large or too small for the house will cause energy waste and discomfort.

An oversized air conditioning unit will use a great deal of energy and will cool too quickly. This will cause the unit to switch off and on more frequently, and it will not run long enough to remove humidity from the air. The house will feel cold and clammy instead of comfortable. The initial cost and installation of this system will also be greater than necessary.

A unit that is too small for the home will run constantly, thus using much energy without ever cooling the house to a comfortable temperature.

In choosing the right size heating and cooling unit, following conventional recommendations may be a problem. In the past, one ton of cooling equipment was suggested for every 500 square feet of living space. In energy efficient houses, however, one ton per 700 square feet is recommended. Computerized sizing of units is generally considered more effective and is usually provided by power companies free of charge.

The important factor to consider when choosing an air conditioning unit is heat gain into the structure. For every 12,000 BTUs (British Thermal Units) of heat gain, one ton of cooling equipment is needed. Many homeowners may need help in assessing heat gain and cooling needs.

When purchasing an air conditioner, it is also important to choose a system that is energy efficient. Room air conditioners are rated by an EER (Energy Efficiency Rating) while central air systems are rated by the SEER (Seasonal Energy Efficiency Ratio). Effective January 1, 1992, only units with an EER rating of 10+ will be sold in Louisiana.

The higher the efficiency rating, usually between 8 and 12, the less energy it takes to run that unit. A rating of at least 10 is usually recommended.

Caution is necessary when buying a central air system with SEER level of higher than 11 as the air delivered from the AC may feel too cold and may not get enough moisture out of the air. Some manufacturers are now incorporating heating pipes which will take care of this problem.

For example, a central air system with a SEER of 10 provides the same amount of cooling as a system with a SEER of 8 while using 25% less energy.

For those people who already have a particular cooling system, and can not change or upgrade it, there are recommendations to follow that can help reduce loss of cooled air and thus reduce energy used in cooling.

1. Be sure the cooling system has been installed properly. All manufacturers instructions should be followed.

2. Keep cool air inside by caulking and weatherstripping, keeping windows and doors closed, and by avoiding heat or humidity producing activities.

3. Maintain the cooling unit. This includes changing the filter at least once a month. A dirty filter can reduce efficiency 5% to 15%.

4. With a window unit, be sure there is adequate circulation near the back of the unit for optimum cooling. Shade unit.

5. With a central air system, be sure that all ductwork is properly insulated and that vents are not obstructed and have no leaks.

6. Keep heat producing appliances away from the thermostat. They could "fool" the thermostat and cause the cooling unit to work harder.

7. Set the thermostat at 78°F. Putting the thermostat down to 72°F can raise cooling costs up to 47%. Also, do not set the thermostat lower than the desired temperature. This will not cool the room faster and it will use more energy.
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8. Do not close off unused rooms. This can cause air flow problems and the unit may have to work harder.

9. Perform maintenance check such as cleaning coils and adding six drops of oil to the motor once a year.

ACTIVITY 2:
Find these words associated with choosing an air conditioner:
thermostat
cooling
humidity ductwork
oversized air conditioner
central air insulation
SEER filter
circulation

A
W
Y
T
I
D
I
M
U
H
A
L
R
C
T I T H R O S S M A E E D I
H A R S T T O O S K A R T E
E P Q C I R C U L A T I O N
R E U O O E C A R T U L L C
M M N E A N E O L D B A R E
O P L O Q E D R O P E L O N
S E E R E T L I F L A R N T
T L T I S A D D T I I V E R
A S R D A R F V E I L N L A
T D D E Z I S R E V O M G L
H A L L R S S U N N A N D A
I N S U L A T I O N M A E I
K R O W T C U D Y C L A M R
A Z U L A T I O C O L I N G

RESOURCES:
Manual for Building Energy Efficient Homes in Louisiana. Louisiana Department of Natural Resources, Baton Rouge, LA, n.d.

Why an Efficient Home? SLEMCO, Lafayette, LA, n.d.

Efficient Air Conditioning, U. S. Department of Energy, DOE//CE-0149, FS 206. 1986.

INFORMATION CHECK
Place a "T" before the statements that are true and an "F" before the statements that are false. After each false statement, explain why it is false.

_____1. Heating and cooling costs account for about 25% of a family's energy budget.
_____2. In Louisiana, heating and dehumidification are the main concerns.
_____3. There are two basic types of air conditioners from which the consumer can choose from.
_____4. Central air conditioning systems have greater comfort but also greater cost.
_____5. If your home does not have central air, it can easily be converted to a central air system.
_____6. An oversized air conditioning unit may cost a little more but it is worth it.
_____7. An undersized air conditioning unit will run constantly and the room will probably never reach the desired temperature.
_____8. Always follow this rule: One ton of air conditioning per 500 square feet of living space.
_____9. When sizing an air conditioner, the important factor to remember is heat gain by the structure.
_____10. EER refers to the energy efficiency of a room air conditioner, and SEER refers to the efficiency of a central air conditioning system.
_____11. Dirty air filters can reduce efficiency up to 15%; therefore, filters should be changed once a month.
_____12. Heat producing appliances should not be placed near the thermostat, since they may make the air conditioning system work harder.
_____13. Unused rooms should be closed off and never cooled at all.
_____14. The best temperature setting for the air conditioner thermostat is 72°F.

TEACHER'S NOTES
ACTIVITY 1:
Have class share results of their surveys.

ACTIVITY 2:
A
-
Y
T
I
D
I
M
U
H
-
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T I - - - - - - - - - - - -
H - R - - - - - - - - - - -
E - - C I R C U L A T I O N
R - - - O - C - - - - - - C
M - - - - N - O - - - - - E
O - - - - - D - O - - - - N
S E E R E T L I F L - - - T
T - - - - - - - T - I - - R
A - - - - - - - - I - N - A
T - D E Z I S R E V O - G L
- - - - - - - - - - - N - A
I N S U L A T I O N - - E I
K R O W T C U D - - - - - R

DEFINITIONS:
1. Dehumidification -
This refers to removing humidity from the air. Humidity or moisture in the air retains heat. Thus a room is warmer if it is humid. Air conditioners reduce humidity in the air.

2. Oversized and undersized air conditioning units -
This refers to installing units that are too large or too small to take care of the actual heat gain of the house.

ANSWERS TO INFORMATION CHECK:
1. False. These costs account for about 50% of the home energy budget.
2. False. Cooling and dehumidification are the main concerns.
3. True.
4. True
5. False. Most homes without central air lack the ductwork for central air. It is usually not worth the conversion.
6. False. An oversized system costs more, but does not keep the temperature and humidity at comfortable levels within the home.
7. True
8. False - Do not always follow this rule. More energy efficient homes may need less.
9. True
10. True
11. True
12. True
13. False. In our climate, the rooms need to be cooled and dehumidified enough so that mold and mildew do not grow.
14. False. Never turn the air conditioner below 78°F. It uses too much energy.

Comments or questions to: TechAsmt@LA.GOV

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