In India, we have hot days and then we have, even hotter days. According to news, every year the heat crosses the past ten years’ record. Bengaluru went all guns blazing to hit a 85-year-old record in April 2016 according to reports. It is important to keep your cool in such hot temperatures. “As the sweltering heat of summer begins to set across the country during the summer months, people all over the country are running to their air conditioners to stay cool,” says Paras Sirohia, chairman & MD, Cruise Air Conditioner.

The Air Conditioner (AC) is an appliance designed to modulate the temperature settings in a fixed area. The cooling is typically done through a simple refrigeration cycle. A regular AC has temperature settings ranging from 15 to 35 degree celsius, as per requirements. Let’s take a look at the various types of these environment modulators.

A glance at various AC types available today

The first step towards being able to decide which AC to buy, is to wrap our heads around the different types of ACs in the market. This guide will focus on the types of ACs available and which would best suit your purpose.

Split AC          

Split AC is the most common kind. This consists of two distinct units, an internal and an external one. The outdoor unit contains the compressor, and is often the noisier of the two. It is connected to the indoor unit via drainpipes and electric cables. Due to no moving parts in the indoor unit, this unit of AC is almost silent. These can be fit into walls, and with the latest designer looks, can add to the facade of the room as well.

Window AC

Another common type is the window AC. A single unit housing the compressor, condenser, expansion valve or coil, evaporator and cooling coil, can often be found attached to the lower level of windows. These are effectively the cheapest cost-effective ACs currently in the market. Being a single unit, it takes less effort for installation.

Tower AC

The Tower AC is similar to split AC in the fact that, both of them have two distinct sections. However the difference here is the indoor unit does not need to be installed on a wall. So, there is no need to redecorate the room around the AC. It occupies space on the floor, and due to its high cooling capacity, is suited to very large rooms.

Cassette AC

This takes on a different form and is designed to be installed on the ceiling of the room. Due to its positioning in the room, the cassette AC provides most uniform cooling in a room. But the odd form factor also comes in the higher price range. These are ideal in saving spaces, as they involve the surface of a room with the least human interaction – the ceiling.

Cube AC

Another type is the cube AC, introduced by Panasonic. It is a type of split AC with the indoor look of a window AC. It consists of propeller fans specially designed for fast cooling. The large intake grill, further adds to its performance. It can be mounted on the wall high up, away from the interference of young children in a room.

Million dollar question: Which Air Conditioner?

The selection of an AC is like any of your gadgets. “Buying an AC is always critical and involves analysing various factors before finalising on the right one,” says Sirohia. You weigh the pros and cons, then you match the features with your requirements and make a selection.

Once you know the features, the big question comes to mind. There are a lot of vendors in the market, with a varied list of options, so which one to go with?

While there are some highly customised equipment in the market, catering to very niche clientele, not every appliance is suitable to every user. People living near the sea would require a different set of features, as compared to the people living in the deserts.

This question can be answered by the application of the AC once it is installed. The use cases of an AC will give a better perspective into how the selection process should go by.

Cooling Capacity

A lot of ACs come with cooling measurements, ranging from 0.75 ton to about five tonnes. The point to consider would be the area to cool, and the number of people in that area.

Room Dimensions	AC tonnage measurements	Available AC configurations
100-150 sq.ft.	0.75 Ton	window/cube
150-250 sq.ft.	1 Ton	window/cube/split
250-400 sq.ft.	1-1.5 Ton	window/cube/split
~500 sq.ft.	1.5-2 Ton	split/cassette
~700 sq.ft.	2 Ton	split/cassette/portable
~1000 sq.ft.	3 Ton	cassette/portable
>1000 sq.ft.	>3 Ton	cassette/portable

This is further affected by the proximity of the intended room to the cooking area or other items that emit heat, as well as the number of people in the room. On knowledge of these parameters, your AC requirements can be calculated.

According to Sirohia, “When it comes to ordering your air conditioner, you’ll want to buy equipment that is readily available for delivery and meets the engineer’s exact requirements to ensure the quickest and easiest installation”.

The Features You Need To Look For Are: 1. High star rating (3 minimum) 2. Blue fin heat exchanger/at least copper with anti-rust coating 3. Increased heat exchanger surface area of both indoor and outdoor units 4. High efficiency fan motor and compressor 5. Tonnage based on your requirements 6. Appropriate features based on requirement 7. Servicing and equipment warranty

After you are done with your purchase and enjoy the cool air, the filters continue to gather dust and other harmful microorganisms (bacteria filter). Regular servicing takes care of this. “The importance of after sales service is also significant to customer satisfaction, particularly if the customer’s capital expenditure on the equipment is significant,” adds Sirohia.

EER & The Star Rating System

Energy Efficient Ratio (EER) is a significant parameter when considering the usage of an AC. It is the ratio of cooling capacity (in watts) to power consumption (in watts). The higher the star rating, better is the efficiency of the system. The effectiveness of an air conditioning system can be appropriately judged by the amount of cooling per unit of power consumed. “Higher the amount of heat removed per hour per unit of power consumed, higher is the efficiency of air conditioner. Also, higher the EER, better is the air conditioner,” adds Sirohia.

If the sales guy quotes some very high number for cooling capacity, it won’t be effective unless the power consumption is similarly reduced. On the other hand, a cooler with less cooling capacity can be effective if it consumes even lesser power which, is generally not the case, since these devices consume heavy power. Star rating is directly proportional to the effectiveness of the AC and hence becomes an important parameter when considering an AC.

How to convert EER to Star Rating
EER	Star rating
<2.3	1 star
2.3<EER<2.6	2 star
2.6<EER<2.8	3 star
2.8<EER<3.1	4 star
>3.1	5 star

              As a general rule of thumb, the above mentioned table is considered for star rating systems in India.

For example an AC with cooling of 4000 W and a power consumption of 1500 W, would work out an EER of 2.67. This would be termed as a three star AC. These are mathematical terms, which are meaningful for analysis, but not so much when standing at a shop and bargaining on the features. Let’s take a look at some of the other parameters, while considering one in a shop.

Additional Features

A good air conditioning unit employs filters effectively, which need to be regularly cleaned and maintained. The wireless operations allow ease of use, whereas the temperature regulation technologies maintain your room to the best of your needs. With timer function, these can automatically modulate the room before your arrival.

The commonly available features are:

1.     Wireless Remote Control: To switch on and off the AC without having to climb some furniture every time.
2.     On/ Off timer: Automatically switch the AC off at night, or when you leave the house.
3.     Sleep timer: Once you go to sleep, it maintains optimum temperature
4.     Dehumidifier: Keeps the humidity in check
5.     Slide-out chassis for easier installation: For ease of installation and removal during servicing

“Air conditioners with more features tend to be more expensive,” adds Sirohia.

We also have advanced features like:

1.     Air filter to remove odours, smoke and germs: Keeps the air inside the room germ free
2.     Reverse cycle for heating: For when the temperature gets too cold, you could heat it up.
3.     Mosquito traps: Now no pesky insects during the summer.
4.     Wi-fi enabled operations: Controlling the AC operations via Wi-Fi.
5.     Auto Clean Function: Cleans out the filters regularly.

With such advanced features to filter out germs, and then cleaning out those filters, these certainly are an added advantage in houses with small children. Remote-controlling these is the norm today. Some of the older window ACs required manual input with no remote facility.

With the involvement of government entities, like the Bureau of Energy Efficiency (BEE), there is a strict adherence to certain safety measures and efficiency issues, and this calls for rigorous safety and performance testing done on the system before launching into the market. Additionally, dedicated government websites maintain records of all the patented and star rated products to prevent fraudulent entities from printing higher star rating on their system.

Some available air conditioners in the market

Usage Parameters: Billing Hours

An AC requires servicing about once a year, costing about a thousand INR, with third-party installation in the beginning about double that amount. For a regular household, a couple of four or five-star rated AC would bring down the electricity bills sufficiently.

A typical 1500 watt AC working 10 hours a day, uses up to 450 units in a month. With the electricity rates different for different regions, and the different star rated appliance, this can range somewhere between, INR 600-2300 for a low star rated device. This electricity consumption in large is due to the compressor, active for about 80% of the operating time of an AC.

Data collected from third-party service providers, and internet. Subject to change

Optimisation: Reducing The Electricity Bill

A better option is to go for a high star rated AC so that, the cooling is comparatively faster. Another useful installation tip would be to avoid putting the AC unit under direct sunlight. ACs are not set up on walls facing direct sunlight. This reduces the efficiency and beats the purpose of installing a high-efficiency appliance in your house.

For a split AC selection, there is another option of installing an Inverter AC. This feature controls the compressor in a way that it uses very less power. In the earlier systems, there was no control over the power consumption of the compressor. Once the compressor starts, it works at full power, till it is switched off. With this newer technology, the compressor is always on, but draws less power or more power depending on the temperature of the incoming air and the level set in the thermostat. This reduces the average power consumption by 30-50%.

However, AC vendors that we spoke to explained that while they try to sell five-star ACs using the efficiency card, a customer going for five-star for the sake of efficiency alone will only find it worth his investment if the ACs are running for more than 15 hours on every day of the year.

Final Decision

With the rapid increase in world temperature, the need for air conditioners has risen dramatically. A lot of innovation is happening and better and more efficient products are entering the market regularly. Inverter ACs are reducing electricity consumption on a daily basis. Even large open areas use AC, places where even cassette ACs are impractical, employ ventilation ducts, to maintain a cool temperature. This would always motivate the manufacturers to bring out something new to the market. Hence it is always beneficial to know what to look for, and knowing your requirements will help in deciding on the right one. After all, you don’t buy an air conditioner everyday.