Air conditioning modifies the air quality indoors, to make it more comfortable. Air conditioners simply absorbs heat energy from one place and releases it elsewhere.
Air Con is used in many offices all year round to regulate air quality, but becomes essential in summer, to reduce the temperature and humidity levels in their home or work place. Air conditioners provide a cool air flow and do more than just dehumidify; many air conditioners units have special filters to remove small particles such as allergens from the air, so are of particular benefit for those with allergies or asthma.

Air conditioners are not to be confused with Evaporative Air coolers, as they work in a totally different way. Air coolers do not use a refrigerant, and are not able to cool the air in humid conditions. They work by passing air through damp pads, and the moist fanned air creates a sea breeze effect in a localized area, so are perfect for small offices where you cannot have outside venting, but just want to create a cool breeze in which to work comfortably.

Air conditioning does 4 vital things:

1) Cooling
Air conditioners offer accurate temperature control. Air conditioning allows you to create the climate in which you feel comfortable. Air conditioned environments makes you feel fresh and active even when it's extremely hot outside.

2) Heating
Air conditioners can offer heating. Air conditioning allows you to enjoy an ideal constant temperature through out the year, regardless of the weather outside. Heating from an air conditioner unit is environmentally friendly compared traditional heating because it takes energy from the outside air and brings it inside.

3) Cleaning
Air conditioners produce clean, fresh and healthy air. Most indoor units are equipped with filters that catch dust, pollen, mould spores and other allergens as well as smoke and everyday dirt found in the air. Air conditioning is therefore an ideal process for those who suffer from allergic reactions.

4) Dehumidifying
When an air conditioner is in cooling mode it dehumidifies the air. Dehumidified air is a much for comfortable environment to be in. Low humidity prevents dust mites and molds populations growing, which is a very positive factor for those who suffer from allergies. Humans feel most comfortable at humidity levels of 40 to 60 %.

Uses of Air Conditioning

Air conditioning can create the perfect environment for you, with the right temperature and a comfortable humidity.

• Air conditioning can have a very positive effect on your personal performance. There is connection between your personal performance and the temperature of your immediate surroundings. An air conditioned environment will improve your performance and energy levels.

• People naturally cool themselves through the evaporation of perspiration from the skin and air conditioning provided drier air, which improved the comfort provided.

• Air conditioning can help those who suffer from asthma and allergies. Air conditioners provide cool air inside allowing windows and doors to remain closed preventing exposure to outside triggers such as air pollution, pollen and mould spores which can cause allergic reactions. Air conditioning units also lower humidity levels indoors which help to control mould and dust mite populations.

• Air conditioned environments prolong the lifetime of equipment in your home or workplace.

How do Air conditioners work?

Air conditioners come in various sizes, cooling capacities and prices: portable air conditioners, split portables, window air conditioners, condensing units on the roofs, and fully integrated air conditioning systems, but they all work on the same principle. An air conditioner removes hot (and damp) air from indoors and transfers it outdoors via a hose. The tube, similar to a tumble dryer hose (around 1m long), has to be vented to the outside ideally through a small venting hole made in the wall or window. For a quick fix (temporary solution) you can, with the use of a flattened oval adaptor supplied, put the hose out of a partially opened window or door. In the more powerful split system mobile type, the heat, along with excess humidity is discharged by the external (condenser) unit.

The hot air from the room is drawn by a fan into the air conditioner, and passes over an evaporator coil, which contains refrigerant. The refrigerant is pushed around the air conditioner by the compressor. The refrigerant is very cold and absorbs the excess heat from the air. This cooled air is pushed out through the front air vents back into the room. The absorbed heat in the refrigerant is transferred to a condensing (hot) coil, which causes the refrigerant to release its heat. The heat is then discharged from the room, either to a second section (split units) or directly into the outside air (mono-block unit). The cycle then starts again, to keep the room at the required temperature. Some air conditioners automatically remove the excess moisture from the air and evaporate it away with the excess heat. This also improved the overall level of comfort, reducing that sticky high humidity. With this type, there is no drip tray or tank to empty, so the only maintenance required is to clean the filter to maintain the air conditioner's efficiency. Other units utilise the moisture that has condensed and uses it to boost the cooling efficiency, in a similar way to water cooling, this is called condensate cooling.

1) Choose the room and then measure the size

The first thing you need to do is select the room in which you would like to install the Air Conditioner. Room air conditioners are an affordable alternative to central-air conditioner systems. New air conditioning models are more energy-efficient compared to older ones. Newer features such as electronic temperature control are more precise than the older knob controls and can also save you money in the long run. Be aware that if you select a room that is connected to an adjacent space through an open door or archway, the two rooms together constitute one room when trying to buy an air conditioner. You will therefore need to purchase an air conditioner efficient enough to circulate air sufficiently for the size of both rooms together. Keep this in mind when you measure how many square feet the air conditioner is going to keep cool.

Air conditioners are available in different sizes, and have cooling capacities from 5,000 BTUs (British Thermal Units per hour) to as high as 30,000 BTUs.

Understanding BTU's

Most air conditioners have their capacity rated in British thermal units ( BTU ). First you will need to work out your rough BTU requirement for your room size. Room sizes for the units are calculated on the basis that 40 watts is needed to cool 1 cubic metre (4Btu/h per cubic foot). Here's how:

1. Multiply length x width x height of the room to be cooled. This = the rooms cubic capacity.
2. If working in feet: Multiply cubic feet x 4. This =Btu/h.
3. If working in metres: Multiply cubic metres x 40. This = the number of watts required.
4. Select which model in the range is closest in cooling capacity to your requirements.

For example, if working in feet and BTU's:

Room size of 12 x 15 x 10 feet =1800 cubic feet

Multiply by 4 = 7200

Therefore an air conditioner with 7200 btu/h or greater cooling capacity would be required.

To choose the right size air conditioner for the space you're cooling see the chart below for initial size, then you need to consider the following:

How many people are in the room? Each person will generate about 2000 BTU worth of heat. You will need to add about 600 BTU's for each additional person using the room over 2 people.

• How many electrical goods such as computers are in the room
• How many windows are there, particularly facing the sun? You will need to add about 10% extra BTU's for a sunny location.
• How hot is the climate where you live?
• Do you need it in the day, when it is hot, or at night time?
• Is the room on an upper storey floor, hot air travels up, so you will need to add about 10% extra BTU's for this too.
• Is the room to be cooled a kitchen? If so you will need to add about 4000BTU's for this.

All these factors will add more heat to the room, so a more powerful unit will be needed. If you buy a unit that is not powerful enough for your room, then it will not be able to cope on the hot days when you really need it. It will improve the air, but it will be acting as a comfort cooler, or spot cooler, taking heat out of the room but not actually reducing temperatures.