Home air conditioner units take heat from any room and expel it to the outside of the building, leaving rooms cool and comfortable. When the unit is switched on air is passed through the unit and over the cold evaporator coil where its temperature is reduced and some of the moisture that makes the air feel sticky is removed. The cooled air is blown back into the room to provide a fresh feeling. During this process air is also used to cool the coil and this is vented through a window or wall via the exhaust hose that comes with all units. The cooling process also produces water which is why units have water tanks which are simply removed and emptied or external drain facilities which allows water to run away continuously via a thin secondary pipe.
The best thing about a unit is that it does get a room or house cool and comfortable and are more efficient than a fan. However they can be costly to operate, often using as much electricity in a day as a fridge does in a week. They are also not environmentally friendly - they expel the hot air out into the environment warming the outside air.If you are buying one look for:
- Adjustable thermostat
- Automatic timer which switches the machine off after a set time
- Washable filters
- Mode settings - some machines have three or four settings which allow them to be used to either cool, dehumidify, fan or heat the air.
- Energy efficiency - check the rating. All air conditioners are graded from A-G for energy efficiency with A grade the best, which will save you money.
- British Thermal Unit (BTU) rating; given to all air con units this is a good guide to how much cooling a machine is capable of
There are greener ways to get cool:
Fans use a fraction of the power of air conditioners as they only have to rotate three blades, but they only move the air around - they don't cool it.
Air coolers are filled with cold water and when switched on, warm air goes over a wet filter so water evaporates providing fresh cool air. More energy efficient than air con units, it does add moisture to the air so can make moist, sticky days even more humid.
In summary air conditioner units for the home can be expensive to buy and operate although if you really suffer with the scorching days you may think this is a small price to pay. Just don't get hot and bothered if you don't get to use it that much over the summer months!
Always refer to the manufacturer's manual for specific details.