10 Important things to know before buying AC this summer

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Air conditioner popularly termed as AC is no more luxury item. With the increasing global temperature and chaos, everyone has the right to work/relax in cool refreshing environment. Beyond rotating fan which struggles to give you cold air just by circulating air, calmness of AC and cold breeze relax you in moment of time.

There can be a number of doubts and confusion while looking for buying AC as per your requirement. Which brand? which capacity? which technology? etc Air Conditioner can significantly blow up your electricity bills, if purchase decision not made with proper information.


In this post we have simplified various terminology and helps you in getting a clear picture for your next most suitable choice of Air conditioner.

1. Split AC Vs Window AC, which is best?

Following is the comparison of window AC and Split AC on various parameters like installation unit, cost, space, efficiency, noise, capacity etc.

Window ACSplit AC
Unit & Ease of Installation Heat exchanges, compressors, motors and connecting pipes are placed on the same base.
Relatively easy installation
It consists of 2 units – Indoor Unit which cools room & Outdoor unit consisting of compressor and heat exchangers.
Installation is not as easy as Window AC
SpaceOccupies more space than split AC. You need to have proper window opening and ventilation space to fit AC in room. Occupies less space. Can be fitted in any room and outdoor unit can be fitted anywhere with the help of connecting pipe.
CostCheaper than the split AC for the same tonnage and energy rating.Costlier than Window AC for the same tonnage and energy rating.
NoiseMore noise (AIR) than Split AC Less noise compared to Window AC
Cooling EfficiencyWindow AC is well suited for smaller room.Split ACs blow more air and can cool more efficiently
Maintenance Easy serviceability Split AC requires proper servicing with help of some expert or professional.

This was about difference between Window and Split AC. But which one should you go for?

Look at your home or room where you wants to install AC. If you are living in flats it is no so easy to find a window space for fitting Window AC.

Installing a Split AC only requires a small hole behind the AC and the same area can be used for installing the upgrade, means if you’re upgrading from 1 to 1.5 ton, you won’t need a bigger hole in the room, unlike Window AC, whose size and shape can vary as per the tonnage and the design of it.

No matter whether you choose window or Split AC, you must know that outer end of both types require proper air ventilation. If you’ll install outer unit in a “not so ventilated” space, you’ll find your AC struggling to provide you effective cooling.

We generally fear that energy bills might skyrocket upon buying an AC, while in reality there’s nothing like that. An air conditioner consumes electricity at full rated power only if you run AC at extreme temperature (like at 18 deg) all the time and not letting the compressor to cut off anytime.

If you keep the AC running at an idle temperature range of 23 to 26, not only it’ll consume less electricity while running, compressor cuts upon reaching the desired temperature also saves a lot. And always use a ceiling fan to circulate the cooling in the room, that’s very important.

2. Which Tonnage AC should I buy?

Buying the AC with correct tonnage is a very important point. Some people often end up buying bigger ACs with more tonnage than required. That is not a good idea as staying in extreme temperatures are bad for health and it also consumes more power and you would feel discomfort at night.

Also, purchasing a less tonnage AC for a bigger area again would cost you more in energy bills as the AC has to work longer in order to reach the desired temperature, thereby costing you more money.

You can refer below table to find out the suitable size tonnage according to your room size

Room Size (Sq ft) Capacity
100-150 sq. ft 1 ton
150-250 sq. ft 1.5 ton
300+ sq. ft 2 ton

If you live in a place where the weather touches the extreme level, like in summers if temperature typically crosses 40-50 deg, you must consider adding 0.5 Ton extra with the required tonnage for an effective cooling.

Now coming to comparison between Window AC and Split AC wrt tonnage, The size of AC unit depends on tonnage. So for window AC, it’s size is directly proportional to the tonnage capacity. Higher the capacity, bigger the size. Because of this, window AC’s are available only up to 2 tons capacity.

In case of split AC, the tonnage varies with outdoor unit size. But since this is installed outside your room so no need to bother about space it is taking.

3. What is Refrigerant in AC?

Refrigerant is a chemical compound which exists either in fluid or gaseous state and have heat absorption capability. Refrigerants have property to change state at very low temperature variation.

Air conditioners contain refrigerant inside copper coils which connects indoor to outdoor unit. Fan blows inside hot air over these refrigerant filled coils. Refrigerant then changes its state to gaseous from liquid. This gaseous refrigerant is now compressed under high pressure to convert it back to liquid state. This work done by compressor. Compressing to high pressure results in extra heat which then blown out with the help of a second set of coils called condenser coils, and second fan.

The refrigerant then cools down and turns back into a low-pressure liquid and this cycle repeats. The indoor unit of air conditioner contains the evaporator and a fan that blows air over the chilled coils and into the room, thereby giving cool air.

Read:- What are different types of refrigerant used in AC?

R 32 refrigerant

It is better to go for refrigerants like R 32, R290, R 600A over refrigerants like R 22(most commonly available) or R 410A. Compared to traditionally used refrigerant R-32 efficiently conveys heat, and reduces electricity consumption up to approximately 10% compared to that of air conditioners using refrigerant like R-22. Furthermore, compared to the refrigerants widely used today such as R-22 and R-410A, R-32 has a global warming potential (GWP) that is one-third lower and is remarkable for its low environmental impact.

4. What is compressor in AC and how does it works?

Compressor also called as heart of AC, is the main component which is responsible for cooling. In case of Window AC, compressor is located in single unit while in case of split AC, it is in outdoor unit.

Compressor circulate the cooling material (refrigerant) necessary for heat exchange through the coils of the indoor and outdoor unit.

So how does compressor works?

The compressor compress the gaseous refrigerant, and this raises the refrigerant’s temperature so that changes it into a high pressure gas. The high pressure forces the refrigerant through a line that leads to the outdoor coil, where the refrigerant releases its heat and condenses into a liquid. The liquid refrigerant then continues its trip to the indoor unit, where the refrigerant evaporates into a gas again and absorbs the heat from inside your home. The refrigerant than returns to the compressor and cycle starts again.

5. Difference between Inverters AC and Non-Inverters AC

Inverter AC runs on the inverter technology, which is quite different from normal technology used in regular split or window AC. Difference is in functioning of compressor.

Inverter is nothing but a device for converting frequency and it controls electric voltage, current and frequency. Inverter air-conditioners vary their cooling/heating capacity by adjusting the power supply frequency of their compressors.

In a regular AC, the compressor works at full capacity when it is on. On reaching the optimum temperature, the compressor switches off and the fan continues to operate. Once, the temperatures rise above the threshold limit, the compressor starts again and works at full capacity. This entails that the compressor works at only two speeds, full and Zero.

Inverters ACs are designed to work at a variable voltage and they consume very less voltage during regular usage compared to a normal star rated air conditioners. If you’re planning to buy an Inverter AC, you can pick even a 3 star rated model as per your budget, don’t wait to make a budget for 5 stars rated model.

6. Why should you pick an Inverter AC over Non-Inverter AC?

When you turn on an Inverter air conditioner, it starts consuming full rated power for few minutes and then eventually the voltage consumption get lowered up to 1/6th of the rated power consumption e.g. if the rated power is 1500W, within half an hour or less, you’ll find that the AC is consuming only 300-400W of energy per hour and for overnight 8 hours running, the AC shall consume only 3-4 units of energy.

Keep in mind that this energy consumption usage pattern you’ll get to see only if you keep the temperature range between 22 to 28, if you keep the temperature lower, the AC shall adjust the power consumption accordingly.

A non-inverter AC does not vary much at energy consumption like an Inverter AC. It relies on the compressor to cut off upon reaching the desired temperature. This is not the case with Inverter ACs. These compressors work at variable speeds. In the Inverter technology, the compressor never switches off. It is always on. But, it runs at varying speeds thereby drawing less power.

DC Inverter Technology, reduces power consumption by maintaining an ideal temperature without frequently turning the compressor on and off.

The benefit of using inverter AC units is that they are highly energy efficient. A 3-star inverter AC is preferred over a 5-star normal split AC. An Inverter AC saves you a lot more in energy bills in the long run. Apart from Inverter split AC, Inverter Window ACs are also available to buy from LG 2018 models.

7. Copper coil Vs Aluminium coil

Air conditioners use coil to cool the air. Two of most important section of AC, evaporating coil and condensing coil is totally dependent on type of coil for efficiency. Copper coil are popular as they cool faster, are easy to maintain and have longer lifespan. While copper coils are generally expensive, they have better heat exchange & anti corrosive properties and are preferred in coastal area.

Most of the AC uses HCFC refrigerant for cooling purpose. HCFC easily reacts with Aluminium and form a corrosive layer on coil, which may cause leakage of refrigerant and low lifespan. Whereas with Copper this possibility is much less.

While everyone check for star ratings, tonnage, key features, brands and price range at the time of selecting a perfect air-conditioner, it is important to note that the efficiency, performance, running cost and lifespan of a room air-conditioner is always highly dependent on two basic factors; Star Ratings and choice of metal used in the condenser coil, evaporator coil and connecting tubes. Same is recommended by International copper association

What is grooved copper coil?

Some of the AC manufacturer are using grooved copper coin instead of normal copper coil. The reason is efficient heat transfer feature. Grooving the inside surface of the tube, increases the surface to volume ratio, mixes the refrigerant, and homogenizes refrigerant temperatures across the tube.

Grooved copper pipe vs normal copper pipe

Aluminium coil are cheaper comparatively yet Copper coil is preferred in air conditioners for following reasons

  • Higher durability and less maintenance cost

  • Better heat transfer support

  • Easy to clean off and replace corrosion if happens

  • Higher tensile strength

  • Can withstand vibration of compressor without leakage of refrigerant

Therefore it is important to look for copper based Air conditioning unit preferably and that too 100% copper coil. 100% copper includes Indoor unit + out door unit + connecting tube

Here are some recommendations

8. Which one to buy? 3 or 5 energy star rating?

Star rating is a measure of energy efficiency of an appliance. You would have seen this on various other home appliances as well like refrigerators, Washing machine, micro-oven etc. It is a five points scale where higher the rating means lower energy consumption and hence better savings.

What is EER? Why is it called ISEER?

The Bureau of Energy Efficiency (BEE) has a grading system called Energy Efficiency Ratio (EER). This is meant for home appliances such as air conditionersrefrigerators and other electrical equipment. Air conditioners are rated in BTU (short for British Thermal Unit) regardless of their capacities and tonnage. This BTU number tells you how fast an air conditioner can cool a room, with a fixed temperature outside.

Since the temperatures across India vary and see extreme changes through the seasons, the EER standards method of calculating performance were less than ideal. Air conditioners consume a lot of energy, resulting in high electricity bills.

Thus, BEE defined a new seasonal EER rating standard called ISEER in India.

It is often seen that while looking for our favourite AC, we could not prioritise energy rating as this might make us to miss some key featured or good looking product.

While comparing the efficiency of different products using the stars

  • you must compare products of the same or similar size

Never ever go for less than 3 star AC or any home appliance in general. It will shoot up your electricity bill.

Inverter technology plays crucial role in energy consumption. A 3 star AC with Inverter technology is almost equivalent to 5 star AC without Inverter technology.

9. Key Features Not to be Missed

There are lots of features which consumers don’t know of but eventually need them once they buy it. There are some popular features like Mosquito Away by LG, PM2.5 filter in Daikin or Panasonic, Auto cleaning of the filter by Hitachi which one should get in their ACs.  So here are some features you should look for while buying an AC:

  • 4-way swing if you’re buying it for drawing room otherwise 2-way is ok for the bedroom.

  • Air Purification (like having 3M or PM 2.5 filter) (Optional but preferred)

  • Showing current room temperature on the AC itself (optional)

  • Quick cool, Jet cool, Himalayan cooling (naming varies with different manufacturers) like features comes handy when you require quick cooling in the room.

  • Mosquito Away (LG exclusive feature) (Optional)

  • Auto-restart (in case of power cut, it must resume automatically)

  • Dehumidifier (comes handy in rainy seasons or for the people who live in nearby coastal areas and face high humidity) (Optional)

  • Night-glow buttons and backlit display in the remote controller (backlit option is hard to find, hence optional)

  • Hot and Cold AC (Very important for me who lives in a place like Delhi, I run my LG hot and cold AC in winters as well for room heating purpose)

10. Service centre and support

Most of the product comes with minimum 1 year comprehensive warranty, 1 year on condenser and 5 years on compressor warranty.

This may varies as per promotional offer.

Some products come with 10 years warranty on compressor from Godrej, Voltas, Samsung, LG etc. Needless to say if you get any better deal on this, you should grab that.

OnsiteGo 2 Year Extended Warranty for Air Conditioners

AC warranty India


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