News - 2017112301 - Air Conditioning Survey: 30% respondents woken up in “too cold” room

Local green group Green Sense has long been paying close attention to environmental issues in the urban area. Multiple scientific surveys have been conducted on both individual and organizational misuse of air conditioning in order to urge Hong Kong to reduce its electricity consumption and carbon emission. Surveys and researches examining air conditioning systems in various transport means and public places such as shopping malls were done throughout this decade. As a part of the annual event No Air Con Night 2017, in August we have conducted street questionnaires at 5 of the most bustling locations over the city, in hope of shedding some light on citizens’ habits of air con usage at home.

A total of 507 responses were collected, with information including clothing choices and sleeping quality in an air-conditioned household, the frequency and duration of air con usage, and the reasons and concerns of using air conditioners.


In 2016 alone, Hong Kong consumed an astounding 14.4 billion kWh of electricity, accounting for 8.2 million tonnes of carbon dioxide. Shall the city strive to relieve climate change and lower its carbon emissions, it would be important to reduce power consumption and use air conditioners smartly.

In summer, citizens mostly stay in air-conditioned environments, including offices, classrooms, public transport and entertainment facilities. These public areas, however, do not allow the adjustment of indoor temperature by the public themselves. As a result, we conducted a survey last year about shopping mall temperatures in the form of street questionnaires and on-site measurement and discovered that some shopping malls still possessed a low indoor temperature. The huge difference between indoor and outdoor temperatures can be detrimental to public health and is a large waste of electricity as well.

On the contrary, at home citizens are capable of controlling air conditioners at will according to their own needs and feelings. Hence it is the question of whether they are using air con wisely to improve sleeping quality or abusing. We wish, at the same time, to raise awareness of air con use with this survey.


In August 2017, we, with the help of volunteers, conducted street questionnaires in 5 places spanning all of Hong Kong Island, Kowloon and the New Territories, namely Central, Mong Kok, Tuen Mun, Sha Tin and Tai Po. A total of 507 valid responses were collected. All results and graphs are available here.


Valid responses amounted to 507. The target group of the survey was Hong Kong residents. Summaries of responses to the 13 questions in the questionnaire are as follows:

  1. (Q1) Over 90% of respondents turn on air-conditioners because the weather is too hot; close to 30% do so to improve sleeping quality; around a tenth use air con for dehumidification. We suggest using a dehumidifier instead for such purpose.
  2. (Q2) Nearly half of the respondents selected ‘expensive electricity bill’ as the main reason for not turning on their air con. A quarter chose ‘carbon emission’ as the main concern, and another 25% chose health concerns such as drying of the skin and respiratory allergies as reasons to avoid turning on air con.
  3. (Q3) Almost half of the respondents adjust the temperature setting of their air con to a suitable 24-26 degree C, while 40% adjust the temperature to 22-24 degrees C.
  4. (Q4) The peak of air con usage was found to be in July to August, during which over 90% of respondents turn on their air con.
  5. (Q5) 73.9% of respondents utilize their air con every day in summer.
  6. (Q6) 42% of respondents turning on air con for 5-8 hours per day, and the proportion of 9-12 hours per day reached 32%.
  7. (Q7 to Q9) Among those who set their air con temperature to 22-24 degrees C, 35% has experienced waking up due to the room being too cold. The same experience was found in 32% of those who set their air con temperature to 24-26 degrees C. These figures reveal that there is room for improvement in using air conditioning. Specifically, the temperature should be set higher, in order not to fail the purpose of improving sleeping quality. This helps save energy and reduce emissions as well.
  8. (Q10) It has been many years since the Hong Kong government launched the Energy Label Scheme. Moreover, in 2009, it became compulsory for air conditioners to carry energy labels. However, we found that more than 40% of citizens do not know which energy efficiency grade their air conditioners belong to. This shows more promotion of the scheme by the government is necessary. We further remind the public to select Grade 1 air conditioners for maximum energy efficiency and refer to data such as energy consumption level when purchasing.
  9. (Q11) Just about all respondents turn off their air con when there is no one at home; 66% clean the filters of their air conditioners regularly; 54% use fans to assist in cooling and turn off air conditioning earlier than necessary to make use of residual cool air instead. Unfortunately, only 13.6% set timers to their air conditioners and only 16.1% use cooling mats. We encourage the public to use cooling mats and to use fans to facilitate air movement in the flat instead of turning on air con for long periods of time.
  10. (Q12-Q13) These questions concern the sex and age group of the respondents.

Conclusions and suggestions

When problems like climate change and extreme weather conditioners become more serious, Hong Kong, as a coastal city, is bound to bear the brunt of the damage. This survey thus aims to raise public concern about air con use and to stress the fact that our daily habits play an important role in affecting global climate.

Compared with previous similar studies, there has been an improvement in people’s choice of clothing and bed covers. However, as reflected by 30% of respondents being woken up by the cold, there is undoubtedly room to further raise the indoor temperature and use air con more wisely, to avoid wasting energy. Despite being in air-conditioned environments most of the time, 40% of residents remain ignorant of the energy label grade of their air conditioners. Other than reflecting the energy efficiency of appliances, energy labels also serve as an indicator of the electricity cost of said appliances. We thus urge the public to select Grade 1 appliances and purchase according to their own household conditions (flat size, number of family members, etc). In addition, we further hope the public would use air con more wisely, such as wearing lighter clothing, adjusting the temperature setting to a more reasonable level, using cooling mats and fans more, and setting timers. These habits can lead to a reduction in the dependence to air conditioning.

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