People working in air-conditioned spaces prefer 24 deg C and warmer: Survey

Straits Times

09-07-2025

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Minister for Sustainability and the Environment Grace Fu speaking at the International Green Building Conference 2025 on July 9.
SINGAPORE – While many commercial buildings in Singapore are cooled to between 21 and 22 deg C, a survey of 5,000 respondents commissioned by the Singapore Green Building Council (SGBC) found that more than half of the respondents expressed a preference for maintaining indoor temperatures at 24 deg C or warmer.
The results of the survey – dubbed the Indoor Comfort Quiz – were revealed on July 9 at the International Green Building Conference 2025 at Raffles City Convention Centre in a summary report titled Go 25 Indoor Comfort Snapshot.
The report surveyed individuals working in air-conditioned environments across various industries , and offers data-driven insights to help business owners, building managers, and workplace experience teams make informed decisions about temperature settings in commercial spaces. Its goal is to encourage the adoption of sustainable cooling measures without compromising comfort levels .
These measures include adopting hybrid cooling alternatives, like setting the air-conditioning at 25 deg C and coupling it with ceiling fans, as well as encouraging employees to dress light .
This comes as Singapore rolled out the Go 25 movement in May 2025 , which encourages Singapore residents to set the indoor air-conditioning temperature in their homes and offices and buildings at 25 deg C. The campaign is an initiative housed under Go Green SG 2025.
According to SGBC president Allen Ang, buildings account for more than 20 per cent of Singapore's carbon emissions, with air-conditioning being a key contributor to building energy consumption.
SGBC also noted that the overcooling in commercial buildings here accounts for as much as 50 per cent of the total energy required for cooling. This results in unnecessary energy usage and contributes to environmental impact. Overcooling refers to the cooling of interiors with air-conditioning beyond the comfort range.
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This, in turn, creates a vicious circle where hotter cities demand more cooling, which generates more emissions and heat, further raising ambient temperatures.
The quiz consisted of five multiple -choice questions on personal air-conditioning habits and preferences, such as their preferred temperature settings and how they would respond if it became too cold . It was built upon earlier research that found 25 deg C as the ideal temperature for balancing human comfort and energy efficiency.
One such research was commissioned by the Ministry of Sustainability and the Environment (MSE) and SGBC, and was conducted between January and April 2025 by Ngee Ann Polytechnic's (NP) Centre for Environmental Sustainability.
The study showed energy savings of up to 12 percent for each degree raised in air-conditioning temperature from 23 deg C to 25 deg C in offices, with no reported increase in occupant discomfort.
Questions in the quiz, adapted from established thermal comfort research globally, were packaged as a personality quiz , where respondents received one of six personality profiles with Singaporean food themes.
'When the air-con temperature is increased above 25 deg C and combined with hybrid cooling methods like fans, it can feel as cool as 23 deg C – while using much less energy,' said Minister for Sustainability and the Environment Grace Fu, who opened the conference.
Referencing the study done by NP , she noted that raising the air-conditioning temperature to 24 or 25 deg C in a typical 3,000 sq m office – about the size of 30 four-room HDB flats – can achieve annual savings of around $6,400 in electricity costs .
In addition to air-conditioning temperatures, the state of the building infrastructure and necessity for upgrading outdated air-conditioning and mechanical ventilation systems also play important roles in achieving sustainable cooling.
In a dialogue with SGBC chief executive officer Yvonne Soh at the conference, Ms Fu highlighted issues caused by improper installation of ventilation systems. These create uneven airflow in air-conditioned areas, leaving some spaces stuffy. To address the lack of air circulation, building owners resort to lowering the temperature, which then leads to individuals working near the air-con feeling excessively cold.
Another resource, the Go 25 Industry Guide for Building Operations, was also introduced at the conference.
This industry guide provides a detailed overview of actionable strategies that support building managers, engineers and operators in implementing the Go 25 initiative. It draws on industry data and best practices to offer recommendations for increasing indoor temperatures in air-conditioned environments without compromising comfort or productivity.
Some of these recommendations include ensuring proper placement of air vents, and encouraging employees to dress comfortably for work.
The Go 25 Industry Guide is designed to assist managers of smaller buildings who may lack the knowledge or expertise to carry out the required adjustments. It provides them with the background, outlines the benefits, and includes a checklist t o guide them through a phased implementation, SGBC said.
'Rethinking the way we cool out spaces isn't just a good-to-have, it's essential for meeting our climate goals... With these tools, we are empowering every stakeholder in the built environment to take meaningful, measurable steps toward a low-carbon future,' SGBC's Mr Ang said.