What is inverter AC?

What is inverter AC?
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A new confusing term is added to an already confusing AC buying experience, it is inverter AC. So what are inverter AC and how are they different from conventional AC, don’t worry read this 5 minute article and you will be a champion when it comes to inverter AC.

An inverter air conditioner is an air conditioner with variable speed compressor which adjusts its speed & tonnage according to the cooling demand and load on the air conditioner. A 1.5 ton inverter AC will work as 0.8 Ton AC if less people are there in room or room is already cooled and the same AC will work as 1.5 Ton AC if the room is packed with people and temperature inside is high.

Before we begin to understand what is an inverter AC? I feel it is important to have a basic understand on how air conditioning works.

How air conditioning works:

Every air conditioner has compressor and evaporator which does the air conditioning and other auxiliary components which help them in doing that.

The refrigerant which is flowing inside the evaporator which is inside your AC unit absorbs heat from the air inside your room and cools the room, the absorbed heat makes the liquid refrigerant to evaporate and become vapour (gas).

This vapour refrigerant is then passed to the compressor which is outside your house. Here the gas is compressed to increase its pressure and the high pressure gas losses its heat to surrounding air and condenses back to liquid refrigerant which goes in the evaporator and the air conditioning process continues.

For a detailed explanation check out this awesome animation video from Learn Engineering on How does air conditioner work.

Now we know how air condition works let’s look into non-inverter and inverter refrigerators.

How Non-inverter air conditioner Works:

Conventional AC Working

A non-inverter standard air conditioner (AC) is designed for peak load performance (summer heat). It has a single speed compressor which runs at maximum speed when needed to provide necessary cooling.

Let’s say you want your room to be cooled at 20 degree Celsius, you set your AC remote to be at 20 degree Celsius. The thermostat on your AC senses the temperature and kicks in the compressor which starts (clear audible sound with vibrations can be felt) the cooling process and as soon as your room temperature reaches 20 degree Celsius the compressor is turned off (clear audible sound of shutting off).

Then the cold air just sits in your room until it gets warmed up by the people and appliances in your room. Once the room temperature goes above the set temperature of 20 degree Celsius by couple of degrees the compressor starts again and the whole process of cooling is repeated again and again.

So in a conventional non-inverter refrigerator the compressor stars and stops frequently and the compressor runs at the maximum speed at all times during operation.

The frequent ON,OFF and maximum speed operation of compressor consumes more electricity which leads to high electricity bill.

Also the room temperature is not constant at all times because of the start and stop of compressor.

How inverter air conditioner works:

How Inverter AC Works

In an inverter air conditioner the compressor is a variable speed compressor which adjusts its speed according to the load on the air conditioner.

Let’s understand this by an example, its summer afternoon outside temperature is 40 degree Celsius you have turned on your rooms AC and set it to 24 degree Celsius. Since the difference between outside temperature and desired inside temperature of the room is so vast the inverter compressor will operate at full speed until the desired temperature of 24 degrees is achieved. Once your room temperature reaches 24 degrees the compressor doesn’t stops but runs at just enough speed to maintain the room temperature at 24 degree Celsius.

The afternoon is passed now and its night time, outside temperature is 30 degree Celsius again you have turned on your rooms AC and set it to 24 degree Celsius. Since this time the difference between set temperature and desired temperature is cut to half of the afternoon value, the inverter refrigerator compressor will run at speed (not max) needed to reach the desired temperature of 24 degrees and once the temperature is achieved compressor runs at just enough speed to maintain the room temperature at 24 degree Celsius.

Inverter Vs Non Inverter AC – Courtesy Daikin

As you can see that in an inverter refrigerator the compressor adjusts its speed based on the outside temperature, heat in the room and other factors which leads to less power consumption whereas in a conventional refrigerator the compressor runs at maximum speed at all times irrespective of the load hence more power consumption.

As the compressor is always ON in an inverter air conditioner the temperature of the room is constant which is more comfortable to the body.

Advantage of inverter AC:

Inverter AC is definitely the future in air conditioning all because of the benefits it has to offer over the conventional air conditioner.

  1. The main advantage of inverter AC is that it saves your electricity bill by almost 30% when compared to an AC of same size without inverter technology.
  2. It is more comfortable to sleep in a room with inverter AC because of the constant room temperature in the room. Once you set the temperature, it will remain constant.
  3. An inverter AC does not make any sound while running due to its lower speed continuously running compressor instead of stopping and starting constantly as in conventional AC.
  4. Inverter AC have a lower operational cost than conventional ACs.

Disadvantage of inverter AC:

The only disadvantage I found in inverter AC is slightly high upfront cost which according to me is a wise investment considering the savings in electricity bill it has to offer.

Power consumption of AC:

Here is a small table to show the power consumption of inverter AC and its comparison to normal AC with energy saving stars. The below table is generated by using data from BEE website and amazon.

AC Type1 Ton AC1.5 Ton AC2 Ton AC
1 Star AC843 kWh1246 kWh 1648 kWh
2 Star AC800 kWh 1184 kWh 1626 kWh
3 Star AC (Inverter or non inverter)743 kWh 1104 kWh 1448 kWh
4 Star AC (Mostly Inverter)645 kWh 945 kWh 1293 kWh
5 Star AC (Mostly Inverter)554 kWh 840 kWh 1113 kWh

Lesser known facts about inverter technology:

There are few misconceptions about inverter air conditioner, I hope the following points help you to get it cleared.

  1. Every compressor has an electric motor, regular motors need 3-4 times more current (more than running current) at startup. So the size of the inverter/generator needed to run any AC increases significantly. But Inverter Technology refrigerators have variable speed motors that start up gradually needing much lesser current at startup. Thus the size of inverter/generator required to power them is small. Thus if a conventional AC needs 5 kW inverter to power it, an inverter AC of the same tonnage can be powered just by a 2 kW or 3 kW inverter.
  2. If you are planning to use Solar PV for your house, then it is the best to use inverter technology air conditioner or refrigerator as it not only reduces the size of PV panels needed to power them because it consumes lesser electricity, but it also reduces the size of inverter to be put along with the PV panel.

Tips to save AC power consumption:

Weather you have inverter AC or conventional non-inverter AC follow these tips to save electricity consumption of your AC.

  1. Set thermostat at 24 degree Celsius for maximum savings.
  2. Clean your AC filters every month to get optimum air flow.
  3. Keep your house under shade.
  4. Make the air conditioned room properly sealed so cold air cannot get outside easily.
  5. Keep compressor unit and AC unit in shade.
  6. Turn off appliances inside your room which are not in use to reduce unnecessary heating of cooled air.
  7. Get a professional to check your AC annually.

You can check out this article to learn more about how to save electricity in AC and this article to know 5 free ways to save your house electricity bill.

Conclusion on what is inverter AC?:

To conclude this article I would say inverter air conditioner are more energy efficient, more comfortable than conventional air conditioners and the reason for that is the variable speed compressor which runs at all time and adjusts its speed according to the load on the AC and cooling demands.


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This Post Has 3 Comments

    1. Jayesh

      Thank you sir, glad it was helpful to you 🙂

  1. swpriya

    Amazing post! Your post is very informative and I felt quite interesting reading it. Your blog images are very nice. Thanks for posting such post and waiting for more in future.

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