AIR CONDITIONER

Most homes in warm climates have air conditioning. For some, air conditioning may be a luxury, but for many, it is a necessity. Given the expense of the equipment and the power to run it, ASHRAE wants consumers to be informed about their air conditioning systems. These ten points should make a consumer more aware of the air conditioning system and better able to care for it and use it well. Should it become necessary to replace that system, seek out a qualified HVAC professional.
1. HOW AN AIR CONDITIONER WORKS

2. WHAT A “TON” OF COOLING IS

3. WHAT GOES WRONG

4. WHAT THOSE FILTERS DO

5. MAINTAIN THE SYSTEM

6. DUCTS MATTER - A LOT

7. HOW TO INCREASE ENERGY EFFICIENCY

8. LIGHTEN YOUR LOAD

9. VENTILATE

10. IT’S NOT THE HEAT, IT’S THE HUMIDITY
What is Air Conditioning?
The first functional definition of air-conditioning was created in 1908 and is credited to G. B. Wilson. It is the definition that Willis Carrier, the “father of air conditioning” subscribed to:
Maintain suitable humidity in all parts of a building
Free the air from excessive humidity during certain seasons
Supply a constant and adequate supply of ventilation
Efficiently remove from the air micro-organisms, dust, soot, and other foreign bodies
Efficiently cool room air during certain seasons
Heat or help heat the rooms in winter
An apparatus that is not cost-prohibitive in purchase or maintenance

HOW AN AIR CONDITIONER WORKS

The job of your home air conditioner is move heat from inside your home to the outside, thereby cooling you and your home. Air conditioners blow cool air into your home by pulling the heat out of that air. The air is cooled by blowing it over a set of cold pipes called an evaporator coil. This works just like the cooling that happens when water evaporates from your skin. The evaporator coil is filled with a special liquid called a refrigerant, which changes from a liquid to a gas as it absorbs heat from the air. The refrigerant is pumped outside the house to another coil where it gives up its heat and changes back into a liquid. This outside coil is called the condenser because the refrigerant is condensing from a gas back to a fluid just like moisture on a cold window. A pump, called a compressor, is used to move the refrigerant between the two coils and to change the pressure of the refrigerant so that all the refrigerant evaporates or condenses in the appropriate coils.
The energy to do all of this is used by the motor that runs the compressor. The entire system will normally give about three times the cooling energy that the compressor uses. This odd fact happens because the changing of refrigerant from a liquid to a gas and back again lets the system move much more energy than the compressor uses.

WHAT A 'TON' OF COOLING IS

Before refrigeration air conditioning was invented, cooling was done by saving big blocks of ice. When cooling machines started to get used, they rated their capacity by the equivalent amount of ice melted in a day, which is where the term “ton” came from sizing air conditioning.
A ton of cooling is now defined as delivering 12,000 BTU/hour of cooling. BTU is short for British Thermal Unit (and is a unit that the British do not use) The BTU is a unit of heating - or in this case, cooling - energy. It’s more important, however, to keep in perspective that a window air conditioner is usually less than one ton. A small home central air conditioner would be about two tons and a large one about five tons.

WHAT GOES WRONG

Unlike most furnaces, air conditioners are complex mechanical systems that depend on a wide variety of conditions to work correctly. They are sized to meet a certain “load” on the house. They are designed to have certain amount of refrigerant, known as the “charge”. They are designed to have a certain amount of air flow across the coils. When any of these things changes, the system will have problems.
If you produce more heat indoors either from having more people or appliance