You bought a brand new AC

Great !!

Now you are worried about the monthly electricity bills that are going to add up to your cost of living.

OK

You can get a general idea of how much power or electricity units your AC will consume in 1 hour, 1 day or 1 month.

Using this you can calculate your monthly electricity bills.

However do note this method is not 100% accurate, it only gives some general or nearby value

The actual air conditioner power consumption per hour or per day will vary and depends on many factors.

You can use this method to calculate power consumption per hour or electricity consumption for any kind of air conditioner – window or split, inverter or normal.

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**General Rule**

For getting a quick insight into the power consumption of your AC.

See the below values, these are power consumed per hour for the respective tonnage AC.

**1 Ton AC = 1000 watts or 1 unit of electricity **

**1.5 Ton AC = 1500 watts or 1.5 unit of electricity**

**2 Ton AC = 2000 watts or 2 unit of electricity**

But this is a very vague and general answer.

Let’s get a more accurate answer.

**How to get Power Consumption of any AC in 1 Hour**

The power consumption for an AC is written on the product itself like this below

But if it’s not written you can still calculate it using the Power Consumption Label of your AC which has a star rating on it.

Use this formula for power consumption

Let’s take an example of Voltas 1.5 ton AC available on Amazon.

**This is 1.5 Ton AC **

Its ISEER rating is 2.92, ISEER rating is Indian version of EER rating

Its Cooling capacity is 5050 watts

Using the formula,

2.92 = 5050 / Power

**Power** = 1729 watt per hour or 1.72 Kilo Watt

**Power** = 1.72 units of electricity per hour

So this Voltas windows AC will consume 1.72 units of power per hour

However, this is only true when the AC runs on max power for the entire time of 1 hour

The value calculated of 1.72 units is the max power this AC can consume per hour.

**Let’s calculate the power it will consume when the desired temperature is achieved.**

After achieving the desired temperature of the room.

**In the case of normal non-inverter AC**, the compressor goes in ON and OFF cycles to maintain the desired temperature.

The compressor runs for 70-80% of the time.

Compressor consumes the majority of the power in AC, rest components – fan, condenser, etc consume 1/10 power of the entire AC.

**Assumption**

- Compressor only consumes electricity in AC
- Compressor runs for 75% of the time

Taking the same Voltas AC

Power per minute when compressor is ON = 1.72 / 60

Power per minute when compressor is OFF = 0

Power per hour =

Power consumed when compressor is ON

+

Power consumed when compressor is OFF

Power per hour = ( 1.72/60 ) x (0.75 * 60) + 0

**Power per hour** = 1.29 kW or 1.29 unit

**In the case of inverter AC**, the compressor may run on 70-90% of max power.

**Assumption**

- Compressor runs on 75% of its usual power
- Only Compressor consumes power

Power per hour = 0.75 * 1.72

**Power per hour** = 1.29 kW or 1.29 unit

So for this Voltas 1.5 Ton AC the power will be varying in ( 1.29-1.72 ) kW

**Power Consumption of 1 Ton AC in 1 Hour**

Using the same method in the above example you can calculate power consumption per hour for your 1 Ton AC

Let’s take my Voltas 1 Ton 5 star window AC

ISEER rating = 3.31

Cooling Capacity = 3520 watt

Power = 3520 / 3.31

Max Power = 1063 watt = 1.06 kW

After achieving set temperature = 0.75 * 1063 = 792 watt = 0.79 kW

**Power per hour = **(** **0.79 – 1.06 ) kW

**Calculate electricity bill for AC**

To calculate the monthly electricity bill for your AC.

Calculate the power consumption first for per hour.

Then calculate the power consumed per day based on your daily usage and then monthly power

Multiply your monthly power consumption with your city’s electricity cost per unit.

**Let’s take an example**

Power per hour = (0.79 – 1.06) kW

Per Day AC use = 10 hours

Electricity Cost = ₹8 per unit

Monthly Bill in worst case = 1.06 x 10 x 30 x 8 = ₹2544

Monthly Bill in best case = 0.79 x 10 x 30 x 8 = ₹1896

**Monthly Bill will vary from ****₹****1896 to ****₹****2544**

**Main Factors affecting AC Power Consumption**

**1. Outdoor temperature **–** **Higher the outdoor temperature more the load on AC, and so more power consumption

**2. Desired Room Temperature **–** **Lower the desired room temperature more the load on AC, and so higher power consumption

**3. (Outdoor – Desired) Temperature **– Higher this difference, higher will be the load on AC and so it will consume higher electricity.

**4. Room Size **– The AC tonnage must be in accordance to the room size. If the AC is too small for a room, then its compressor will run on the max power always consuming higher electricity.

**Tips to save power**

If your monthly AC bills are too high for you.

You can use some tips to save your money.

- Service your AC regularly
- Keep the air filters clean
- Run the AC on 23-26 degree celsius instead of 18 degree celsius
- If your AC is too old, sell it
- Run ceiling fans with AC