It’s chilling summer and most of us might be planning to purchase AC and doing internet research. But the main thing which comes to our mind is the power consumption of AC. As this have a significant effect on our pocket. This post outlines, EER (Energy Efficiency Ratio), ISEER (Indian Seasonal Energy Efficiency Ratio) and the method to calculate the power consumption of 1.5 ton AC in terms of kWh or Unit.
For the sake of calculation of energy / power consumption of AC, we will take 3 STAR, 1.5 ton Split AC as reference. But the method is well applicable for 1 Ton or other tonnage of Window / Split AC. The very first thing is to note down the details provided on the name plate of AC. Following parameters should be noted from the name plate:
Cooling Capacity of AC is defined as the amount of heat energy removed from room. It is given in terms of BTU / hour. BTU stand for British Thermal Unit and it is defined as the amount of heat energy required o raise the temperature of 1 pound of water by 1 degree Fahrenheit. If you calculate this, you will find that
For 1 Ton AC, the cooling capacity is 12000 BTU/hr. Since 1 BTU = 1055 Joule, therefore , cooling capacity of 1 Ton AC in terms of Watt will be
Similarly, if we consider 1.5 Ton AC, the cooling capacity is 18000 BTU/hr, which means 5275 Watt approx. Thus cooling capacity is fixed by the tonnage of AC.
Energy Efficiency Ratio or EER is a parameter which determines the utilization of input power supply to cool the room. Obviously, every consumer should look for better utilization of input power supply as it will help to reduce the electricity consumption and hence bill.
EER of AC is a ratio of Cooling Capacity to the input power supply consumed. Different STAR rating of AC has different value of Energy Efficiency ratio.
BEE (Bureau of Energy Efficiency) has set a standard to rate AC on the basis of EER. Refer the table below for relation between STAR rating and EER for Jan 1, 2014 to Dec 31, 2015.
From the above table it is clear that if EER lies in between 3.10 to 3.29, the AC will be given 4 STARs. But what does this information mean to a consumer?
The better the EER value, the lower will be the power consumption AC and hence lower will be impact on you pocket. So if you see two 4 STARs ACs, one having EER value of 3.15 and another having 3.25, then you should go for second AC as its EER value is better.
ISEER stands for Indian Seasonal Energy Efficiency Ratio. It is defined as the ratio of total amount of heat energy removed from the indoor air in a year to the total amount of power consumed annually.
The concept of ISEER was launched in India in 24th August 2016. This concept is introduced as the ambient temperature throughout the year varies and hence the cooling capacity of AC also varies to maintain a fixed indoor air temperature. In inverter AC, the tonnage of AC varies with the heat load. This greatly helps in improving the energy efficiency. As the name suggest, it is seasonal energy efficiency ratio. The better the value of ISEER, the better will be the efficiency of AC.
Based on the concept of ISEER, a new methodology to rate the AC has been adopted. In this method, the ISEER value is calculated for the entire year assuming the temperature profile for the year and 1600 operating hours of AC in a year. Based on the value of ISEER, the STAR rating is given to ACs.
Power Requirement | AC 230 V, 50 Hz |
---|---|
Power Consumption | 1600 W |
How Much Is A 5-Ton AC Power Consumption?
Let’s take as an example a 3-star 1.5-ton AC. It has a max. wattage of about 2,000W. How do we come from 2,000W to how much it will cost to run it for an hour?
First, we have to calculate the average running wattage. Here we presume that a 1.5-ton AC runs on 58% cooling output:
Running Wattage (1.5-ton 3-star) = 2,000W × 0.58 = 1,160W
That means that running such a 1.5-ton AC will use 1.16 kWh per hour. To figure out how much that costs, we need to multiply the kWh spent by the price of electricity. Here we take the US average of $0.1319/kWh electricity cost to calculate that:
Running Cost Per Hour (1.5-ton 3-star) = 1.16 kWh × $0.1319/kWh = $0.153/hour
As we can see, an average 3-star 1.5-ton AC unit will cost about $0.153 to run for 1 hour. If we run it for a whole day (24 hours), we just multiply this number by 24:
Running Cost Per Day (1.5-ton 3-star) = $0.153/hour × 24 hours = $3.67/day
You can use this principle to calculate the running cost of any 1.5-ton AC unit. The key info you will need is how many watts does a 1.5-ton AC run on. Here is a shortlist that roughly estimates the maximum and running wattage of 1 – 5 star AC units:
1.5 Ton AC Star Rating: | Maximum Wattage (Est.): |
1-Star 1.5 Ton AC | 2,400 Watts |
2-Star 1.5 Ton AC | 2,200 Watts |
3-Star 1.5 Ton AC | 2,000 Watts |
4-Star 1.5 Ton AC | 1,800 Watts |
5-Star 1.5 Ton AC | 1,600 Watts |
Using these wattages, we can automatically estimate the running cost of 1.5 AC using this calculator:
Just insert the star rating, the price of electricity in your area, and how many hours you want to run your 1.5-ton AC. The calculator will tell you how much you will have to pay for the electricity:
Example: Let’s say you want to know how power much does a 1.5-ton inverter AC power consumes per hour. These inverter units usually have a 5-star rating.
In the calculator above, choose a ‘5-Star’ unit, slide the second slides to match the electricity cost in your area, and set the third slider (running hours) to ‘1’. You can see that the power consumption of a 1.5-ton inverter AC is about $0.12 per hour (presuming US national average electricity prices).
To help you out, we have made some calculations about how much it costs to run a 1.5-ton AC per hour, day, week, and month and gathered them in this chart:
Factors affecting ACpower consumption:
Power Consumption of Inverter and non inverter air conditioners.
Based on data from BEE in 2018 (the levels are similar in 2021), below is the representative (median) sample of power consumption of Air Conditioners of various tonnage and star ratings:
0.75 ton | 1 ton | 1.5 ton | 2 ton | |
1 Star AC (mostly non Inverter) | 627 | 843 | 1246 | 1648 |
2 Star AC (mostly non Inverter) | 596 | 800 | 1184 | 1626 |
3 Star AC (mix of Inverter and non Inverter) | 542 | 747 | 1104 | 1448 |
4 Star (mostly Inverter) | 464 | 645 | 945 | 1293 |
5 Star (mostly Inverter) | 450 | 554 | 840 | 1113 |
Annual Electricity Consumption (Units or kWh for 1600 hrs) based on data from BEE |
FAQ
How much electricity does a 1.5 ton inverter AC consume?
How much power does inverter AC consume?
How can I calculate my 1.5 ton AC power consumption?
How much electricity does inverter AC use per hour?