Bring Down the Cost of Cooling

How Do I Pre-Calculate My AC’s Electricity Bill?

It really is scorching this summer and we are only in March. Come April, the weatherman has predicted a further 2-3 degree Celsius rise in temperature. As the country witnesses electoral campaigns, politicians are sweating it out in the hot sun as the temperatures are reaching above 36 degree Celsius from 11 am to 4 pm in many parts of India. With ceiling fans already running at top speed, it looks like an air conditioner (AC) is a must to see us through the summer.

Satyaprakash is an automobile engineer who spends a lot of time at the factory, in workshops and sheds. With temperatures unusually high, Bengaluru, where he lives, has been dubbed the “hottest Metro”. He has made up his mind to buy an AC on EMI before the month-end. He is worried about the electricity bill burning a hole in his pocket and is seeking information on how to pre-calculate his electricity consumption, conserve energy and keep his power bill low.

Make Your AC Energy Efficient

The efficiency of a room air conditioner is measured by the energy efficiency ratio (EER). If the EER rating of your AC is high, it will work more efficiently.

EER = Cooling capacity (in British thermal units [Btu] per hour)/ power input (in watts).

For the purpose of calculation, let us assume Satyaprakash has purchased a 5 Star, 1.5 Ton AC. There are many options available at the Bajaj Finserv EMI Store hosted online by Bajaj Finserv EMI Store.

Regardless of the manufacturer, let us say the AC he bought has a BTU = 5353.4 and EER = 3.59

One unit of power = 1 Kilo watt Hour (kwh)

He has to apply a simple formula to calculate the total power consumption and that is:

BTU/EER = 5253.4/3.59

= 1490 Watts/Hour

= 1.49Kw/Hour = 1.49kwh (1.49 Units per hour)

If Satyaprakash runs the AC for 6 hours in a day, the total power consumption for 1 day would be 1.49 x6 = 8.94 units

Per month = 31 x8.94 =277 units

Let us say the energy cost is Rs 4/Unit

The total estimated power consumption cost at the rate of 6 units per day)

= No. of Units x Unit Cost

= 277 x Rs 4

= Rs 1108

So, Satyaprakash will run up an electricity bill of Rs 1,108 per month. He can go ahead and purchase that AC on EMI as he can afford it;  when we last heard, he was torn between a Panasonic CU-TS18SKY with a 35% discount and an LG Ks-Q18Hnzd with zero down payment.

Source: Lloyd AC Energy Saving Chart

Budget Your AC, EMI, Usage

You too can adopt a similar strategy if you are planning to purchase an air conditioner. Once you find an AC on EMI that fits into your budget, you can try the same calculation. You don’t have to go for a 5 star rated air conditioner if you find it expensive –but believe us, it will be cost effective in the long run. However, you can also base your decision on the number of hours of usage. If it is less, even a 3 Star AC will do, say experts arguing that only an AC that is run up to 8 hours needs to be 5-star rated to make a real difference to your electricity bill.[4]

Bear in mind that the above calculation is illustrative and the bill will vary depending on the tonnage of the AC, power ratings, ambient temperature, size of the room to be cooled and the number of hours of usage. The chart below, for instance, is prepared with five occupants in mind.

Source: The Economic Times

You may also find these simple tips useful to optimize usage:

• Allow cool air into your house at nights, when hot days are forecast.
• Seal the windows properly
• Keep the filters clean and check for blocks regularly to make it work efficiently
• Do not keep the AC running when you are in the bathroom or kitchen and the room is unoccupied
• Choose an ideal setting for the thermostat –not too high or too low, compared to the outside temperature –if the difference is too much, the AC has to work harder and the compressor works for longer.

Do not forget to check on after-sales service, warranty, availability of service centres near your home and cost of spare parts before you buy an AC on EMI. By opting for a brand that is advertised profusely, you should not end up burdened by maintenance costs.

Read more about energy saving air conditioners: 5 Best Energy Saving Acs on the EMI store