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Inverter AC, Non-inverter AC and BEE Star Rating: What are the differences?

Last Updated on April 14th, 2021 by RefrigeratorPro Team

If you are planning to purchase an AC, then chances are, you would have come across this terms such as inverter AC, BEE rating, ISEER value. We will go through each in detail and try to clear all your doubts in this post.

How does an AC work?

Simple explanation of how AC works is this-

Refrigerant flows in the coils and this process is aided by the compressor. Refrigerant is compressed into hot liquid by the compressor and sent to condenser (outside unit) for loosing heat. This process is aided with the help of a fan that blows hot air onto the condenser. After this, refrigerant flows to evaporator coils, where the refrigerant is cooled further. Now this cool refrigerant flows to the indoor unit and a fan blows from inside towards the coils. This cool air then flows into the room. And the refrigerant goes back to the condenser and the process is repeated.

As you can see, compressor is the heart of an AC. Better compressor technology will give better results. Thus, the main difference between inverter AC and non-inverter one is how the compressor is regulated.

What is Inverter Air Conditioner?

Inverter ACs are in-demand these days because of their energy saving aspect. An inverter AC contains an inverter that senses the load required and adjusts the speed of the compressor constantly based on the current temperature, thus providing effective and optimum cooling. It means that an inverter AC’s compressor constantly regulates the temperature.

This is different from Non-inverter ACs, where the compressor will switch off on and off after fixed intervals of time to keep the temperature under the desired range instead of specific temperature. Usually, window ACs do not come with inverter technology. Almost all top AC brands in world come with inverter ACs.

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Inverter AC vs Regular AC – Differences

Below table gives all the key differences between the Inverter and Non-Inverter AC.

Non-Inverter ACInverter AC
Its compressor only switches on or off instead of adjusting as per the current temperatureIt contains an inverter drive that controls the motor speed (and compressor speed) as per the required load.
The compressor switches on and off automatically after fixed intervalsThe compressor runs constantly
Produces comparatively more noise while runningGives quieter operations.
They consume more power as they are not efficientThe save good amount of power due to efficient usage by inverter
Lifespan is less comparativelyLonger life as compared to non-inverter units
Suitable for open spacesNot suitable for open spaces
Desired temperature goes slightly up and down because it switches on and offTemperature does not change because it is constantly monitored by the inverter
Price is lower than Inverter ACsMore expensive as compared to non-inverter ones

Below is cute illustration to explain why inverter ACs are more comfortable. Note: It is only for illustration and actual conditions may vary.

Advantages of Inverter AC

1) Precise Temperature control

Cooling is quite accurate because the temperature is controlled constantly by the inverter.

2) Long Life Span

Since the compressor does not start at full speed or shut down abruptly, the wear & tear is quite less. These changes are smooth and constant, requiring lower power. This increases the lifespan of the compressor

3) Low Noise

Most of the window ACs run on regular compressor. Whenever the compressor switches on, noise level increases considerably. However, an inverter AC starts with low speed and increases the speed gradually. Even then the noise levels are lower.

4) Lower Energy Usage

Inverter AC consumes less energy as it is controlled by this digital inverter. In fact, as compared to a non-inverter AC, it can consume up to 50% less energy. This saves a decent amount in electricity bills.

As you can see, inverter AC is better in terms of energy, noise, power bills and efficiency as compared to a non-inverter AC. The only major disadvantage of Inverter AC is its buying cost. Even that should not be a concern because the power bills will be lower and over the years, you should be able to recover the cost.


As per BEE, Indian Seasonal Energy Efficiency Ratio “means the ratio of the total annual amount of heat that the equipment may remove from the indoor air when operated for cooling in active mode to the total annual amount of energy consumed by the equipment during the same period”

In simple terms it is the cooling capacity per unit energy consumed. Thus, higher ISEER means more energy efficiency.

  • 5 star AC will have ISEER more than 4.5
  • 4 star AC will have ISEER value between 4 and 4.49
  • 3 star AC will have ISEER value between 3.5 and 3.49
  • 2 star AC will have ISEER value between 3.3 and 3.49
  • 1 star AC will have ISEER value between 3.1 and 3.29

It is used to give star rating to air conditioners in India. This also gives further breakdown to buyers so that that can determine more efficient AC under a given star rated AC. For example, 4.7 ISEER rated 5 star AC is more efficient than 4.5-ISEER, 5 star AC.

BEE Star Rating

Room air conditioners are mandated by the BEE to display star rating on every AC that a manufacturer offers. Higher star rating means higher energy efficiency. 5 star is the highest, while 1 star is the lowest star rating. Thus, 5 star AC will save most amount of energy, helping in saving on your electricity bills. BEE has done a great job in making the star rating system more stringent over the years. The image below shows the progress of these ratings over the last decade.

As you can see, a 5 star AC in 2013 will not even qualify for a 1 star AC in 2021. This shows how energy-efficient ACs have become today.

Difference Between 3 star, 5 Star and Inverter AC

Biggest advantage of inverter AC is its energy saving aspect. Air conditioners come with BEE star energy rating and ISEER rating, where higher rating means better energy efficiency. Inverter AC and non-inverter AC both come with star energy ratings.

Below table shows the power consumption of different types of ACs in kWh.

 0.75 Ton1 Ton1.5 Ton2 Ton
3 Star Non Inverter62782812351548
3 Star Inverter AC55072610771344
4 Star Inverter AC4996589721208
5 Star Non Inverter AC57676011301412
5 Star Inverter AC4215578151005

These numbers represent energy consumed when the AC is run for 1600 hours. For example, 3 star non-inverter AC will consumes 627 units of power when run for 1600 hours. Also, these are approximate numbers.

As you can see, 5 star inverter AC is one of the most energy efficient ACs in the market. Also, this data also shows that inverter AC is better than non-inverter AC irrespective of star rating. This means that talking about inverter vs non-inverter AC, inverter AC is a clear winner in terms of energy efficiency.

Also, 5-star inverter AC is one of the most expensive ACs in the market if we talk about buying cost.

Difference Between 3 star and 5 Star AC

Energy Efficiency

As per this data we can come to following conclusions:

3 Star Inverter vs 5 star Inverter AC

  • A 5 star rated inverter AC is at least 30% more energy efficient as compared to 3 star rated inverter AC.

3 Star Non-Inverter vs 5 Star Non-Inverter AC

  • A 5 star rated non-inverter AC is around 9% more energy efficient as compared to 3 star rated non-inverter AC.

3 Star Non-Inverter vs 3 Star Inverter AC

  • A 5 star rated inverter AC is around 50% more energy efficient as compared to 3 star rated non-inverter AC.


Inverter AC is usually costlier than non-inverter AC, irrespective of star rating. This is because even a 5 star inverter AC is more efficient in saving power as compared to a 3 star non-inverter AC.

Among non-inverter ACs, 5 ACs are more expensive as compared to lower rated non-inverter ACs.

However, this is the buying cost. You have to keep in mind that AC can account for 10% of a your overall electricity bills. Thus, overall cost in the long run is not very high for energy efficient ACs.


Inverter ACs give better cooling because the temperature remains same as there is no up and down cycle like in non-inverter ACs. It helps in setting best AC temperature for saving electricity.

However, as far as star rating is concerned, 3-star ACs are more powerful than 5-star ACs in general. This is because 5-star ACs are built for optimal cooling to ensure cooling at lower power consumption. On the other hand, 3-star ACs are powerful, as there is no such constraint.


Higher energy efficiency means more eco-friendly. Thus, 5 star inverter AC is most eco-friendly and 3 star non-inverter AC is least eco-friendly.

Types of Inverter Compressors in AC brands in India

All best ACs in India offer inverter ACs. We have listed most well knows inverter compressor technologies here.

Dual Inverter

You will find dual inverter ACs in LG brand. It is sometimes also called twin inverter (Toshiba) or dual inverter rotary compressor (Blue Star).

Dual inverters are more efficient than regular ACs in giving faster and precise cooling.

Regular inverter ACs use BLDC motor to control compressor speed. Dual inverter compressors are more advanced version of these BLDC motors. Regular inverter ACs come with single cylinder-shaped rotary compressor that rotates at high speed, which produces good amount of vibration and noise. This is one of the major drawbacks of BLDC motors.

However, the twin-rotary compressors of dual inverters turn with a phase difference of 180 degrees. This means that the AC unit is more stable while running in full capacity. More stability leads to less vibration and thus, less noise. On top of this, it also ensures variable tonnage. Which means that dual inverter ACs can regulate cooling tonnage from .4 tons to even around 2 tons.

In fact, we have spoken to many LG customers who own dual inverter ACs and we have received positive feedback in terms of noise.

Intellisense Inverter

The most common inverter compressor in Whirlpool ACs is the Intellisense Inverter. This inverter enhances the efficiency of the inverter. It is able to achieve this by adding multiple sensors for optimum sensing and cooling.

These sensors detect the number of people in the room and outdoor temperature and adjust the cooling accordingly. Intellisense inverter provide silent cooling with a low noise level of 35 to 40 dB.

Triple Inverter

Triple inverter is an advanced inverter technology from Samsung. As per Samsung, it gives 67% faster cooling even at high temperature of 68 degree Celcius. It is one step ahead of dual inverters and give more efficient cooling as compared to dual inverters. However, it is more complex technology, therefore, it can mean higher cost of maintenance in case of break down.

Most of the ACs can work decently at around 50 degrees, therefore this is quite high ambient temperature. However, we do not believe that it will be of much use in most parts of the country because temperatures do not go up to this level.

Expandable Inverter

Hitachi ACs use expandable inverter. These inverters are good at expanding their heating capacity as per external temperature changes. It works well Even in the extreme climatic conditions by expanding its cooling capacity and reducing time to reach desired cooling temperature.

Also, these inverters are designed keeping in mind tropical Indian climate with high heat and humidity. It gives optimised performance in peak loads and cuts heat as well as humidity efficiently.


What is the difference between Inverter, Digital Inverter and Smart inverter ACs

There is not much difference between inverter, digital inverter and smart inverters. Some brands prefer to use ‘digital inverter’ instead of ‘inverter’, while a smart inverter is an inverter where a special microprocessor controls the inverter-compressor. In short, different brands prefer different terminologies and the difference between them is minimal.

Is there a Window AC with inverter technology available in market?

Usually window AC do not come with inverter inverter technology, but LG is one of the few brands that offer window inverter air conditioners.

Do all ACs come with BEE star rating?

All room air conditioners are mandated to have energy star rating displayed on its label.

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