Lying awake in bed, I struggled to sleep. My skin was sticky with sweat even though I'd showered not long ago. The fan, whirring at full blast, offered little relief. This was my second day trying to wean myself off the air-conditioning, and I was failing miserably.

Before you roll your eyes, hear me out: My bedroom, by quirk of design, is the warmest room in the house. It is a greenhouse in the morning and stuffy on most evenings. Which is why I tend to switch on the air-con before I sleep, setting it at 28 deg C (the room actually cools to 27 deg, according to my mercury thermometer).

Using the air-con, like drinking bubble tea, is a bad habit. After all, it is a notorious energy guzzler, and contributes to the urban heat island effect and global warming. By cranking up the air-con, we make the environment warmer, which in turn fuels a demand for more air-con - a vicious circle.

This seems all the more grim when you realise Singapore is heating up faster than the global average. Local temperatures are 1.8 deg C higher than they were in 1948, while global temperatures have gone up by about 1.1 deg C from pre-industrial times, which ended around 1850.

Another reason to swear off the air-con, of course, is money. Recently, SP Group's electricity tariffs for households went up by 3.1 per cent due to the higher cost of fuel.

I've been doing the maths: leaving the 2.5kW air-con on for eight hours every night at full blast could cost up to $150 a month at the latest rates. My family spends less than this, since we don't make it work too hard, but it is still a far cry from the $3 or so for using a fan.

When I did an informal poll of my friends last week, most of them said they have an air-con at home. Some reserve it for the hottest of days, while others switch it on when they sleep, or when their doors are closed during Zoom meetings (the air-con becomes an excuse to keep out nosy family members). Only one friend said she does not have an air-con - her family did not think it was worth it.

Four in five local households have an air-con at home, according to the Singapore Department of Statistics' 2017/18 household expenditure survey. In 1987/88, this was one in five. By 1997/98, this had risen to nearly 60 per cent.

When I was growing up in the 1990s and 2000s, a time when non-air-conditioned buses were still a thing, our family used the air-con sparingly. On warm nights, I went to the bathroom for relief - splashing myself with cold water and sprinkling prickly heat powder on my skin.

Today, I am a sybarite: the capitulation to heat begins early in the evening with the flick of a button. While the home air-con is ubiquitous in Singapore, using it still feels like an indulgence. I am addicted to the comfort it provides, but like most addicts, I feel guilty.

Recently, I turned to Google to find alternative ways of staying cool. One suggestion was a DIY "air-con" - fill a saucepan with ice cubes and blast a fan over it, so it sends cool air wafting your way. (Which could end in a sizzling mess, given the numerous electrical appliances and wires I have next to my bed).

Other tips: block out the sun with curtains; open doors and windows to set up a cross breeze; use solar film on windows; or ensure your ceiling fan, if you have one, turns anti-clockwise so it creates a downdraught. People who don't want to go cold turkey can also set a timer so the air-con switches off after a while.

The biggest obstacle to kicking my air-con addiction is my belief, misplaced or otherwise, that the air-con makes me a more productive worker - that a cooler temperature is more conducive to the forming of thoughts.

As it turns out, the air-con began as a tool for industrial productivity. Willis Carrier, the father of the modern air-con, came up with it in the 1900s not to cool humans down, but reduce humidity levels in a printing firm and save the pages from swelling up in the summer.

The air-con would later find a firm fan in Singapore's founding prime minister Lee Kuan Yew decades later. "It changed the nature of civilisation by making development possible in the tropics," he said in 1999.

"Without air-conditioning, you can work well only in the cool, early morning hours, or at dusk. The first thing I did upon becoming prime minister was to install air-conditioners in buildings where the civil service worked. This was key to public efficiency."

But the environmental toll of air-con use is worrying. By 2040, it could constitute up to 40 per cent of Asean's overall electricity demand, notes media company Eco-Business in a 2018 report.

In Singapore, household electricity consumption went up by 22 per cent during the circuit breaker last year.

Associate Professor Lee Poh Seng, programme director of the consortium Cooling Energy Science and Technology Singapore, says: "Given that residential air-con systems are smaller in capacity and hence less efficient compared with the commercial building chillers, the overall energy consumed for cooling in Singapore is likely to increase."

Prof Lee believes in a "holistic approach" to the cooling conundrum - exploring more energy-efficient technologies; reducing the heat gain of buildings through passive design; and conserving energy, such as using air-con only when it is hazy or unbearably hot.

He says that an example of a more energy-efficient cooling system would be the upcoming Tengah Build-To-Order estate, whose residents can subscribe to a centralised cooling system that will pipe water from rooftop chillers to people's homes.

The air-con is bad for the environment, and it costs money; but there is another reason I want to use it less - a niggling suspicion that it can make me sick. Could there be any truth to this?

Health experts I consulted said using an air-con has potential benefits - it can make people feel more comfortable, improve their sleep and filter out pollutants and allergens such as dust and mould.

These allergens, however, can also build up in the air-con. A poorly cleaned air-con can cause health issues, so it should be serviced regularly.

Dr Adrian Chan, a respiratory physician and intensivist at Mount Elizabeth Novena Hospital, adds: "Cold air can potentially irritate the nasal and sinus linings, resulting in nasal discomfort and runny nose."

But one should not overlook other potential causes such as dust or mould, which can trigger allergic rhinitis in some people, he says.

Dr Jenny Tang, a paediatrician at SBCC Baby & Child Clinic who has a special interest in asthma, lung, sleep and allergy, says: "Changes in temperature, cooler temperatures, exposure to increased dust, allergens and moulds in circulating air may trigger symptoms in these individuals (those with allergic rhinitis or vasomotor rhinitis), including nasal congestion, runny nose, sneezing or nasal itch."

The air-con also reduces humidity, which can dry the eyes, nasal passages and skin, and increase the risk of respiratory tract infections and flare-ups of atopic eczema.

Asked if it increases the spread of Covid-19, she says it is not the air-con itself, but "reduced airflow and ventilation in an enclosed air-conditioned environment" that can lead to higher virus concentrations.

So, will 2021 be the year I quit the air-con? As we head into the cooler months of November and December, I think I ought to have another go at relying less on it.

I think of the Chinese saying "xin jing zi ran liang" (being calm keeps you cool), and realise the best way to stay "cool", so to speak, might be to do the sensible thing in the face of a climate crisis and rising electricity costs.

Baby steps: I'll start by setting a timer on my air-con. If that fails, well, it might be time to stock up on ice cubes for that saucepan.