Choosing an efficient air conditioner

Choosing an efficient air conditioner
As the summer is starting to grill us, many people have already started installing Air conditioners in their homes.

The most important thing to look for with an air conditioner is the star rating. You need to work out what size you require for the task and then choose the most efficient model that will perform the task.
The two main types of air conditioners for household use are window-wall systems and split systems. While both can be equally efficient, split systems tend to be more efficient for a particular size range as their components are generally less constrained by size (although this is not always true). Split systems have the advantage of being quieter indoors during operation but they are also more expensive. Some larger houses may choose ducted or packaged units. Be sure to check the stars before you buy.
A new innovation in air conditioner technology is the use of an inverter or variable speed drive in the motor system that drives the compressor (comes with Voltas, Hitachi and Onida now). While these systems tend to look less efficient at full load (ie their star rating at rated capacity is not always as high as conventional air conditioners), they tend to be very efficient at part load operation, which is a more common mode in a typical household. So if you are likely to use an air conditioner for long periods because you live in a hot climate, it may be worth considering an inverter system. They are, however, more expensive to buy, as a rule.
Sizing an air conditioner
The output capacity is a measure of the amount of heat that will be removed (cooling) or added (heating) to the room/s in your house by the air conditioner. The output range you need will depend upon your particular requirements. Air conditioner outputs are measured in kilowatts (kW). As an approximate guide for sizing a room unit allow:
125watts (0.125kW) per square metre of floor area to be cooled in living areas;
80 watts (0.080kW) per square metre of floor area in bedrooms.
These estimates depend on the climate and the efficiency of your house design (orientation, glazing and insulation levels).
It is advisable to get a full heating or cooling load calculation from an authorised air conditioning installer or manufacturer before you buy.

Simple thumb rule is that 1.5 tonne will do good for a 200 to 250 sq.ft area. And 1.0 or .8 tonne for areas lesser than 200 sq.ft.


Best suggestions as a user of AC: Go for brands like Hitachi and O General.