How does a 5-star air conditioner differ from a 3-star?

People often wonder about the star rating of air conditioners. Nowadays, a 5-star air conditioner is better than a 3-star. Let’s try to understand the difference between a 3-star and a 5 star air conditioner. The main difference lies in the energy consumption, which is less in a 5-star AC. Therefore, with a 5-Star AC, you use less electricity, and your energy bill will also be lesser. It’s also visible in the 5-star window ac price which is higher than a 3-star.

The electricity consumption depends mainly on the usage time or the number of hours the AC is in operation. If you want to understand the difference between a 3-star and 5-star AC, it’s essential to see the calculation of savings possible by buying a 5 Star AC Vs. a 3 Star AC. 

Difference between 3-star inverter AC and 5-star inverter AC

The following table provides the minimum ISEER values needed for an inverter AC to become a 5-star or 3-star AC.

Star rating Minimum ISEER Maximum ISEER

1 star                    3.10                     3.29

2 star                    3.30                     3.49

3 star                    3.50                     3.99

4 star                    4.00                     4.49

5 star                    4.50

According to the table, the minimum ISEER value should be 4.5 for a five-star inverter AC, while for a 3-star inverter AC, the minimum ISEER needs to be 3.5. ISEER considers the time an inverter AC is in use for 1600 hours in a year.

If the Cooling load is “C” and the electricity consumption is “F” for 5-star and “T” for 3-star, the cooling load “C” will remain the same for both the 3 Star and 5 Star inverter AC.

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Therefore, for a 5-star AC

ISEER Value = Cooling load ÷ Electric load

 4.5 = C ÷ F

 Hence, electricity units consumed by 5 Star inverter AC, “F” = C ÷ 4.5

 While electricity units consumed by 3 Star inverter AC, “T” = C ÷ 3.5

The Ratio for annual electricity bill for 5-star to 3-star inverter AC

 = C÷4.5 : C÷3.5

 =1÷4.5 : 1÷3.5

 =0.2222: 0.2857

 = 1: 1.2858

How much Power do you save with a 5-star inverter AC?

On average, the annual electricity bill for a 3-star inverter AC will be 28.58% more than a 5-star inverter AC. So, if the electricity bill for a 3-star inverter AC is Rs.1, 000 per month, the bill for a 5-star AC will be Rs.778, saving Rs.222- per month or 22.2% saving in total electricity bill with a 5-star inverter AC compared to a 3-star inverter AC.


What is the per-hour running Cost for an inverter Air Conditioner?

Since, for ISEER calculations, the number of hours an ac should operate is 1600 hours, you can easily calculate the per-hour consumption of Power for the air conditioner. However, the specifications of ac must include the annual power consumption figure. If you divide the annual power consumption by 1600, you can get the hourly power consumption of an AC or the average cost to run an Air Conditioner per hour.

However, it’s essential to understand that the 3-star vs. 5-star inverter AC power consumption displayed in the table are theoretical figures. Moreover, an inverter AC with a 5-star rating uses the latest technology to reduce electricity consumption. After going through this article, you will know why a 5-star window ac price is higher than a 3-star ac.