Before you choose an air conditioner (AC), first thing you need to do is to understand your room in terms of average people using them at a time, electrical equipment, furniture & appliances that are part of the room. A living room will be occupied by more number of people on an average & will probably have more appliances that may comparatively more emit heat. So, you'll be better off with higher capacity AC in a similar sized living room than a bed room, which probably will be occupied with in the evening & night hours.

Exposure to direct sunlight is also another important factor for air conditioning. If you plan to use AC in a room that is exposed to direct sunlight, then the AC will have to put in more effort. Also, ceilings that are exposed to direct sunlight heat more resulting in higher ambient temperature & thus require higher capacity AC.



Split and Window ACs

Residential air conditioners are widely available in 2 physical forms - split & window.

  • Split ACs are made up of two parts - outdoor unit & indoor unit. As the moving parts like compressor along with condenser are outside the room (outdoor unit) split ACs are more silent compared to window ACs.
  • While window ACs are great for smaller rooms, Split ACs have following advantages: quicker cooling, easier installation, lesser noise, more suitable for rooms with lesser ventilation, energy efficient operation & ease of service.
  • Considering these advantages, its recommended to opt for split AC unless space for installing outdoor unit is a constraint.

Non-Inverter & Inverter ACs

  • Split ACs are available with fixed speed compressors and variable speed compressors (widely known as inverter ACs). In fixed speed compressor or regular AC, the compressor is either off or on. When it is on, it works at full capacity and consumes full electricity it is designed to consume.
  • When the thermostat reaches the temperature level set in the AC, the compressor stops and the fan (in AC) continues to operate. When the thermostat senses that the temperature has increased, the compressor starts again. The variable speed compressors in Inverter AC on the other had has ability to work on variable speed. Hence it can meet the fluctuation in power demands.
  • When inverter compressor needs more power; it gives it more power. When it needs less power, it gives less power. With this 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. The speed and power of the compressor is adjusted appropriately.
  • Average daily usage should govern selection of either fixed speed compressor AC or Inverter AC. if you plan to use AC for shorter duration (approximately 3 hrs a day, 4 to 5 months a year) you can opt for fixed speed compressor AC. If you plan to use AC for more hours daily than this or throughout the year, you should then consider investing in inverter AC.

Copper & Aluminium (PFC) Condenser

The material used for condenser coils used in AC affects their efficiency, their ease of cleaning and maintenance. Two types of condenser coils are used in ACs - copper & aluminium.

Pros & Cons of both these condensers are:


  • Durability
  • Better Reparability
  • Better air circulation through the fins (round tubes)
  • Costly
  • Relatively lower on efficiency


  • Higher Efficiency
  • Lower refrigerant volume needed
  • Better heat exchange (flat tubes - thus higher
    surface area for heat exchange)
  • Lower Reparability

It's important to look for corrosion protective coating applied on condenser & higher warranty on condenser.


You can use following formula to arrive at approximate tonnage rating (Tr or ton) that will be ideal for a particular room size:

AC Tonnage = (Length X Width X Height in feet) 1000

For example, if a room is 10 feet in length; 8 feet wide & 10 feet high, then - (10 X 8 X 10) / 1000 = 0.8. Hence recommended AC would of 1 Tr (or Ton) capacity.

However, you also need to consider capacity increment of approximately 0.5 Tr if any of the following conditions are also applicable for the room:

  1. Room has more than 2 windows or a bigger / full-sized window
  2. The ambient temperature of exceeds 38°C
  3. The room is situated on or above 3rd floor
  4. The room is on top-most floor or terrace is directly above the room


  • Bureau of Energy Efficiency (Ministry of Power - Government of India) has started standards & labeling program with the objective of providing the consumer an informed choice about the energy saving and thereby the cost-saving potential of the marketed household and other equipment.

New 2018 Energy Rating Table as laid down by the Bureau of Energy Efficiency (BEE) applicable from 1st Jan 2018

The Indian Seasonal Energy Efficiency Ratio (ISEER) is the Co-efficient of performance expressed in (Watt-hour/Watt-hour). Instead of being evaluated at a single operating condition like EER, it represents the expected overall performance over time - in this case - for a typical year's weather as per Indian conditions. ISEER is an energy efficiency ratio that represents the expected overall performance of a typical year's weather as per Indian conditions.

The ISEER is thus calculated with the same indoor temperature, but over a range of outside temperatures 24 – 43°C (based on national weather data for 54 cities across India) and is the BEE approved the measure.

Note that, the Seasonal Energy Efficiency Ratio (SEER) is calculated with the same indoor temperature but over a range of outside temperatures from 21°C - 35°C. It is used in European climate, not representative of Indian Climate and hence not the BEE approved the measure.

It's important to understand that, not only star rating is important while making the purchase decision but also understanding ISEER is equally important and one should always opt for higher ISEER ACs to get maximum energy efficient ACs. There are 6-star or 7-star performance ACs available in Indian market & opting for such ACs will ensure long-term energy efficiency & thus savings.


  • Refrigerant is a fluid / gas that runs through condenser coils & compressor of an AC & takes out heat from room & disposes it in the atmosphere. There are various types are refrigerants available and are being used in ACs basis of their thermodynamic properties.
  • The most common refrigerant in the past was a CFC like R-12. In the 1990s and 2000s, the CFCs were replaced with HCFCs (hydrochlorofluorocarbon) and the most common HCFC refrigerant being R22. More than 50% of Air Conditioners in India still use HCFCs. However, HCFCs are just marginally better than CFCs as they contain chlorine, which is harmful for the environment. As per Indian Government’s plan, HCFCs will be phased out from India by the year 2030.
  • HFC refrigerants like R-410A & R32 are ozone friendly i.e. they don’t deplete the ozone layer however they still have global warming potential. India has also embraced HFC phase-out under Montreal Protocol.
  • Hydrocarbons or HC refrigerants like R290 are the most environmental friendly refrigerants available as of now & are completely halogen free, have no ozone depletion potential and are lowest in terms of global warming potential.
R290 0 20
R32 0 716
R410A 0 2100
R22 0.040 1790

It's important to opt for AC with environment friendly refrigerants like R290.


Technological advancements have made possible manufactures to offer much more than just cooling with ACs. So, you should evaluate ACs based on following must have features as well:


Air Purification

Its important to opt for AC with filtration system with anti-bacterial & anti dust filters helps you to maintain air inside room free from viruses, bacteria, fungi, dust particles, hairs, spores, etc.


Uniform Cooling in the room

Many a times users complaint about uneven cooling (e.g. - person/s sitting near the AC experiencing colder temperature & person/s sitting in the same room but away from AC experiencing warmer than ideal temperature) inside the room. Modern ACs come equipped with intelligent sensors that avoid this phenomenon and ensure uniform cooling inside room by regulating air throw of AC.


Power Saving mode

With AC being one of the largest power consuming devices; it’s necessary to look out for ACs with built in power saving modes.These modes ensure best running of AC ensuring better cooling with maximum power saving. Also; the ideal temperature to operate an AC is 24 degrees. This provides sufficient cooling to the user, but also ensure efficient operation.



Ability of AC to work as dehumidifier & relieve excess humidity in the room. This helps in smoother operation in monsoon months.


Sleep Mode

Ability of AC to automatically adjust room temperature (by increasing temperature periodically & then returning to set temperature) to ensure comfortable sleep.



Few ACs come equipped with active carbon deodorizer which help in eliminating odours & deactivating other harmful gases.


Installation & Warranties

Correct installation is extremely critical in for optimum performance on any AC. Hence installation by certified & trained technician is desired. There are few manufactures that offer free standard installation by certified technicians as well.AC is an electro-mechanical equipment with parts like compressors & condenser which are exposed to direct atmosphere & thus exposed to dust, rain, harsh sunlight, etc. So you must pay attention to warranties that are being offered by manufacturers on these critical component. Higher warranty ensures worry-free product experience.