Air Conditioners Case Study

Types of Air-Conditioners:

The different types of air-conditioners are:

1. Window A/C

2. Split A/C

3. Floor Standing A/C

Size of Air-Conditioners

Generally, the size of the air conditioners is different for different companies. Recommended size of the window opening for installing a window A/C is 17”x27”.

Window A/C sizes (approximate) :

A/C Capacity

Dimensions (approximately) – (WxHxD) in mm

0.75 Ton


1 Ton


1.5 Ton


2 Ton


Source: Blue Star A/C Catalog

Split A/C sizes (approximate) – For Indoor Unit only:

A/C Capacity

Dimensions (approximately) – (WxHxD) in mm

0.75 Ton


1 Ton


1.5 Ton


2 Ton


Source: LG A/C Catalog

Note: After the study of sizes of A/Cs for three different companies (Voltas, Blue Star and LG), it has been found that the sizes of A/Cs for different companies don’t differ much for similar capacity and type.

Unit for Measuring Energy efficiency of Air Conditioners

An air conditioner’s efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units per hour) to the power input (in watts). The higher the EER rating, the more efficient the air conditioner.

What is “TON”?

It is a rating term used for estimating the cooling capacity of an air conditioner which is equivalent to 12,000 BTU per hour.

Effective Cooling Area Covered by 1 Ton A/C

Based on size alone, an air conditioner generally needs 20 BTU for each square foot of living space. Other important factors to consider when selecting an air conditioner are room height, local climate, shading, and window size.

Ignoring all other factors, a one ton A/C can cool 600 sq. foot area considering a normal room height (10 feet).

Selecting an Air-Conditioner

Size of the Room: The required cooling capacity for an air conditioner depends on the size of the room being cooled: Window air conditioners generally have cooling capacities that range from 5,500 BTU per hour to 14,000 BTU per hour.

Size of the A/C: Proper sizing is very important for efficient air conditioning. A bigger unit is not necessarily better because a unit that is too large will not cool an area uniformly. A small unit running for an extended period operates more efficiently and is more effective at dehumidifying than a large unit that cycles on and off too frequently.

Power system of House: The electrical system of the house should meet the power requirements. Room units operate on 115-volt or 230-volt circuits. The standard household receptacle is a connection for a 115-volt branch circuit. Large room units rated at 115 volts may require a dedicated circuit and room units rated at 230 volts may require a special circuit.

Star Rated A/Cs: The Bureau of Energy Efficiency has set up a technique to measure the amount of energy consumed by A/C (and other electronics) by implying a star rating to different electronic devices. This step was taken to make people (buyers) aware of the energy efficient devices present in the market and ultimately reducing the energy consumption by use of more efficient devices.

So, it is always preferred to buy electronics with HIGHER STAR RATING to get more energy efficiency.


Smaller window air conditioners – Those drawing less than 7.5 amps of electricity – can be plugged into any 15- or 20-amp, 115-volt household circuit that is not shared with any other major appliances.

Larger room air conditioners – (Those drawing more than 7.5 amps) need their own dedicated 115-volt circuit. The largest models require a dedicated 230-volt circuit.

Prices of Air-Conditioners:


Window A/C (Rate*)

Split A/C (Rate*)

0.75 Ton



1 Ton



1.5 Ton



*Prices on August 2008 as per survey on Ansari Road A/C Shops.

Installing an Air-Conditioner:

1. Do not locate the air conditioner above electrics and electronics because they may be damaged by condensation from the discharge air grates on very humid days.

If you mount the air conditioner near the corner of a room, look for a unit that can direct its airflow in the desired direction for your room layout.

If you need to mount the air conditioner at the narrow end of a long room, then look for a fan control known as “Power Thrust” or “Super Thrust” that sends the cooled air farther into the room.

North facing walls are the best to install A/C as they receive the least amount of solar radiation.

Next best are the South facing walls. As both the East facing and West facing walls get direct sun heat, the unit has to work harder to provide the same amount of cooling.

The A/C unit should be installed at a height of about 12” to 60” from the floor because if the unit is installed near the floor surface, the filter of the A/C may get dusted and might stop working after some span of time. If the unit is placed near the ceiling, it will turn out to be less effective as it will cool the top air first.

Reader Interactions


  1. ankit says

    Well! In case of Indian
    Well! In case of Indian context “water coolers” are generally used. And now with the use of “ducting” Indian homes have fully air conditioning coolers installed.

    Summers isn’t HOT anymore….

  2. Rohit says

    Water coolers don’t work in
    Water coolers don’t work in areas with very high humidity like Mumbai and other coastal areas… So for those places air conditioners is the precise option..

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