To cool down? No need to turn on the air con!

With the average global temperature rising every year, the frequencies of turning on the air conditioner have been intensifying in recent years. In 2019, Hong Kong consumed 4.48 billion kWh of electricity [1], of which air-conditioning made up around 30% (1.34 billion kWh of electricity) of the total [2], which equates to releasing  7.44 million tonnes of carbon emission to the planet. Once the carbon dioxide (CO2) concentration increases in the atmosphere, it acts like a thicker glass roof of a greenhouse trapping the heat in the atmosphere, which accumulates the temperature of the Earth. If we are more relying on air conditioning when the weather gets hotter, forming a vicious positive feedback in heating up the planet. Therefore, reducing the usage of air conditioner as well as diminishing carbon emission would be a better way to cool down the temperature!

Meanwhile, climate change has reached the tipping point that we could not neglect. In the first half year of 2020, many countries and regions worldwide set a new record of high temperature. According to the statistics from National Oceanic and Atmospheric Administration (NOAA), the average global temperature for the first half of this year was recorded higher than the last century by 1.07°C. This record is the 2nd highest of June since 1880 after 2016 was recorded as the second warmer [3].

The first half of the year had warmer-than-average conditions across the continents, particularly in central, northern and eastern Europe, plus North Asia, in which Siberia has encountered the most significant temperature change. For example, Verkhoyansk, a town located in the northeast Russia had recorded 38°C on 20th June 2020 [4]. After this record is verified by World Meteorological Organization (WMO), it would be the highest temperature recorded in the Arctic Circle. Referring to the analysis done by Nation Centers for Environmental Information (NCEI) scientists, the year 2020 is most likely to rank in the top five of the warmest years on record [3].

Under this pandemic condition, people spend more time at home, and may increase the usage of air conditioning at home. When the climate change is increasingly severe, we should live a greener way by reducing carbon emission. We could start by using less air conditioning.

If you wish to turn on the air conditioner under certain circumstances, here are some tips for you to go greener!

  1. Select and use air conditioner with Grade 1 energy label
  2. Adjust and keep the room temperature between 24 °C and 26 °C
  3. Cooperate with electric fans to use less air con
  4. Turn on air con in the auto mode
  5. Adjust the wind deflector to horizontal direction
  6. Select and use “inverter” air con
  7. Clean up the air filter regularly
  8. Keep the door and windows closed when air con is on
  9. Switch off unnecessary lighting and heating appliances
  10. Switch off the air con once you feel cold!


  1. Census and Statistics Department, ”Hong Kong Energy Statistics 2019 Annual Report”, https://bit.ly/3jVsQjm
  2. Electrical & Mechanical Services Department (2020), “Hong Kong Energy End-use Data 2019″, https://bit.ly/2EwuRST
  3. National Centers for Environmental Information (2020), “Assessing the Global Climate in June 2020”, https://bit.ly/310zWdJ
  4. The Copernicus Climate Change Service (2020), “Arctic Siberia’s unusual warm spell continues”, https://bit.ly/2P5BNs6