A key aspect that manufacturers stress in AC product description is the star rating. Most of the AC models come with a 3 star or a 5-star rating and the price difference between the two is around Rs.5K.

Prudent consumers would obviously wonder if the extra cost gets negated by the energy savings in the long run. So, let us explore in detail what are the key differences between 3 star and 5 star AC, its implication on your electricity bill and help you decide which one to choose.

Star Rating of An AC

The star rating of an AC gives you an idea about its power consumption. 5-star ACs consume the least power, while a 1 star AC consumes the most.

However, not all 5-star ACs are made alike. Even between 5-star ACs, you find a noticeable difference in the power consumption. This is because for a split AC to be classified as 5 Star, its ISEER rating has to be above 4.5. While most of the 5-star models have an ISEER value of around 4.5-4.7, certain models have ISEER of as high as 6.1, implying a far better energy efficiency.

A 3 star AC on the other hand has an ISEER rating of 3.5 to 3.99. Note that the ISEER ratings of window AC and split ACs are different for a particular star rating.

These star ratings are valid till June 2022 and may change thereafter. You should always check the BEE label validity before purchasing an AC because every two years, the label upgrades. So a 5 star AC in is 2019 would be just a 3 star AC in 2022.

ISEER

ISEER refers to Indian Seasonal Energy Efficiency Rating. It is calculated as a ratio of the cooling seasonal total load and the energy consumption for the same. The total load indicates the cooling efficiency of the unit. So, an AC with high ISEER would have excellent cooling efficiency but still consume less energy. These values are found by conducting tests at temperatures ranging from 24- 43°C for 1600 bin hours.

When considering the energy efficiency of an air conditioner, it is important that you give more significance to the ISEER rating than the star rating.

Typical Power Consumption of a 3 Star AC

As mentioned earlier, a 3 star split AC has an ISEER value of 3.5 to 3.99. The power consumption varies depending on the tonnage type of compressor and the ISEER rating.

The BEE label provides an indicative power consumption on their labels. These are the consumptions at ideal, test environments and will vary according to real-life conditions. Rather than considering the absolute values, use these to get an idea about how power consumption varies depending on the ISEER, compressor type and tonnage.

For ACs with fixed speed compressor-

Tonnage	ISEER	Power consumption
1 Ton	3.5	1 unit
1 Ton	3.99	0.9 unit
1.5 Ton	3.5	1.5 unit
1.5 Ton	3.99	1.35 unit

A 1 ton split AC with an ISEER of 3.5 has a power consumption of around 1 unit, whereas a 1.5-ton split AC has a power consumption of 1.5 units per hour.

A 1 ton split AC with an ISEER of 3.99 has a power consumption of around 0.9 units, whereas a 1.5 ton AC will take about 1.35 units per hour.

For ACs with variable speed compressor ( inverter compressor)

Tonnage	ISEER	Power Consumption
1 ton	3.5	0.88 unit
1 ton	3.99	0.68 unit
1.5 ton	3.5	1.2 units
1.5 ton	3.99	1 unit

A 1 ton split AC with an ISEER of 3.5 has a power consumption of around 0.88 units, whereas a 1.5-ton split AC has a power consumption of about 1.2 units.

A 1-ton inverter split AC with an ISEER of 3.99 has a power consumption of around 0.68 units and a 1.5 ton AC consumes 1 unit.

Manufacturers often have a tendency to make ACs in such a way that its ISEER reaches the bare minimum for a star rating. If it falls towards the higher end of the range, they try to push it to the next star rating slab. So, you will find the majority of 3 stars ACs have an ISEER of about 3.5-3.6

Related reading: What is dry mode in AC?

Typical Power Consumption of a 5 Star AC

As per the present BEE label, 5 star split ACs have an ISEER value of over 4.5.

For inverter split AC,

Tonnage	ISEER	Power consumption
1 Ton	4.5	0.62 unit
1 Ton	6.1	0.45 unit
1.5 Ton	4.5	0.89 unit
1.5 Ton	5.75	0.68 unit

A 1-star split AC with an ISEER rating of 4.5 has a power consumption of around 0.62 units. The highest ISEER rating of 6.1 was awarded to a Hitachi model and it consumes just about .45 units per hour.

A 1.5-ton split AC with an ISEER rating of 4.5 has a power consumption of around 0.89 units, The highest ISEER of 5.75 was awarded to a Panasonic model that consumes just 0.68 units per hour.

Fixed-speed split ACs with 5-star ratings are hard to come by.

Price Difference Between 3-Star and 5-Star AC

For this comparison, we are gathering the prices from Amazon. The prices mentioned below are accurate at the time of publishing and may vary from time to time.

A typical 1-ton split AC with 3-star rating costs around Rs. 24,000 to 30,000. Some models even cost up to 36,000 depending on the features they have.

A 5 star 1-ton split AC on the other hand starts from around Rs. 30,000 and may cost as high as Rs. 39,000

A 1.5-ton split AC with 3-star rating ranges from Rs. 30 to 38K. The same tonnage with a 5-star rating typically costs anywhere from Rs. 35-45K or even more.

As you can obviously see, a 3-star AC costs significantly less than a 5-star AC. Let us now examine a few models to see how long it takes to catch up with the price difference.

Power Consumption Vs Initial Price Difference of 3-Star and 5-Star AC

For comparing the price difference of a 3 and 5 star AC and the long term running cost, we are comparing models from LG, a premium brand and AmazonBasics, a budget-friendly option.

For the sake of calculation, we are considering that the AC will be used only during four summer months for about 8 hours each. So, it comes to a total of around 960 hours. If you plan to run the AC for an extended duration or for office, it is better to opt for an energy-efficient 5 star AC as the long term cost of running a 3 star AC would be much higher.

We are using the power consumption figures from the BEE labels as the actual figures may vary depending on the temperature you set and other ambient conditions.

AmazonBasics’ 1.5 ton Wifi enabled AC with 3 star rating costs about Rs. 33000, while the same model with 5 star rating costs Rs. 38000.
The 3 star AC uses 0.64 units per hour, while the 5 star AC uses 0.52 units per hour. So, the 3 star AC uses 614 ( 0.64 x 960) units, while the 5 star AC uses approx. 500 ( 0.52 x 960) units of electricity. Considering the national average cost of Rs. 6.09 per unit, annually, you save about Rs. 695 during the four peak summer months. It would take about 7 years to break even. But, if you use it for a longer duration, you break even much earlier too.

LG 1.5 ton Dual Inverter Split 5-in-1 convertible AC with 3 star rating costs Rs. 37500, while the same model with 5 star rating costs Rs. 43,800. You may notice a year’s difference in the model name. But, as BEE has extended the validity of the 2021 rating till June 2022, they both fall under the same label period. A price difference of around Rs. 6300 can be noticed. The per-unit energy consumption of the 3-star model is 0.65 units, while the 5-star model uses around 0.51 units per hour.

As you can see, irrespective of the initial price, the energy consumption of both models is almost the same. Owing to a higher price difference, it may take up to 9 years to break even. If you use the AC for a longer duration, of course, it breaks even way quicker.

Conclusion

As you can see, the price difference between a 3-star and 5-star AC comes to around Rs. 5-6K, depending on the model. If you are using the AC for your home at just the peak summer hours, then, by all means, opt for a 3-star AC. The energy savings are not substantial enough for the premium you have to pay upfront.

But, if on the other hand, you are planning to use an AC throughout the year, for your office or even for your home, then, the energy savings become substantial enough. You will save around Rs. 2046 ( 0.14 x 8 x 300 x 6.09) per year if you use the AC for 8 hours for 300 days a year. So, you will recoup the initial premium in just around 2.5 to 3 years.

( Disclaimer- The calculations are done as per energy consumption declared in the BEE label and under ideal conditions. They may vary depending on various external factors, which may in turn change the energy savings and time to recoup the initial investment on the AC.)