The rising heatwaves in India are fast proving to be a cause for concern. According to a McKinsey Institute report, there exists a 9% chance of 250-360 million Indians getting exposed to heatwaves by 2030. The probability of 700-1200 million people being exposed to such heatwaves increases to 14% by 2050. 
Air conditioners are proving to be an efficient and affordable cooling solution to counter the heat. With an increase in the sale and purchase of air conditioners, rising temperatures will lead to an increase in air conditioner usage. However, high usage can subsequently invite high electricity bills. In order to manage one’s expenses, it is important to use your air conditioner in a prudent manner. In order to do so, understanding the most economical settings to fine-tune your AC can go a long way. Read on to find out what the most economical setting for an air conditioner is. 

Working on an AC

When an air conditioner is switched on, it takes the hot air inside the room and passes it through the evaporator coil inside the compressor. The now-cool air is pushed back into the room. This process is repeated until the room temperature is similar to that of the thermostat. The following factors affect the electricity load of an air conditioner: 
  • Indoor temperature
  • Outdoor temperature
  • Thermal insulation of the room
  • Thermostat setting

The above factors are true for all kinds of ACs - split, window, and portable AC. 

Thermostat Settings

When an air conditioner is switched on, the compressor works to achieve the desired temperature. Assuming the initial temperature to be about 35 degrees celsius, the AC will have to work to get it between 25-18 degrees celsius. Now, since the compressor will have to work longer to achieve and maintain the latter temperature, the electricity consumption will also be concurrently higher as opposed to the former temperature. 

As a rule, the lower the desired temperature, the longer the compressor will have to work to achieve and maintain that temperature, and, aggregated over a period of a month, the greater the electricity bill garnered. 

The most economical temperature

Now that the functioning of an air conditioner’s compressor is clear, the next step is to evaluate the ideal temperature of the thermostat for the most cost-effective cooling. According to the American Society for Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), the ideal temperature of the thermostat should be between 23.5-degree celsius and 25.5-degree celsius during the summer months. According to the American Council of Energy Efficiency Economy, you can save 3-5% of electricity from being consumed with every 1-degree Celsius increase in the temperature settings. Setting the thermostat within this range ensures not only a comfortable atmosphere but also effective cost-saving. Turning on the ceiling fan to assist the circulation of cold air can also help to achieve the desired temperature. 
  1. Determining the amount of energy-savings
  2. In order to understand how much electricity can be saved by altering the temperature settings, there’s a simple formula one can follow:
  3. Percentage of Savings = (new temperature - old temperature) / (outside temperature - old temperature)
  4. For instance, setting the thermostat to 25-degrees Celsius from the previous 20-degrees Celsius, when the outside temperature is approximately 45-degrees will result in 20% savings.


In some instances, one may feel that the AC is not cooling, but that is simply because the outside temperature is very high. However, maintaining the thermostat levels within the range mentioned above ensures that the room is effectively cooled and the electricity bills are also kept in check.