Turn that air conditioner off/on?

‘It’s too hot in here, and I want the air conditioner on now!’

‘Actually, I’m comfortable with things the way they are.’

This conversation – which Mrs Tall and I had at 3:00 AM one morning in the third week of May – was unprecedented. It turned on its head our long-standing debate over sleeping temperature. For years, I’ve been the one who’s started whining for the air conditioner somewhere in March or so, whereas Mrs Tall’s been happy to wait until at least May.

This particular night, we’d gone to sleep with our ceiling fan on, and were using light cotton blankets. But instead of me waking up all hot and bothered, I was sleeping soundly, and Mrs Tall was uncomfortable. Of course, who was I to disagree with Mrs Tall’s preferences, so on the air conditioner went – for this first time this year.

If you’re an expatriate in Hong Kong, making an adjustment to the summer heat can be tough. It took me quite a few years to reach a point at which a Hong Kong summertime didn’t make me miserable, and a few years more after that to acknowledge that turning on the air conditioner wasn’t the solution to a whole range of cultural adjustment problems.

That is, to me, at least, air conditioning was quite symbolic. Turning it on was a sign that I was not giving in to my Hong Kong surroundings, that I was determined to insist upon and assert my ‘right’ to feel ‘comfortable’ in the same way I did back home. When Mrs Tall and I were first married, for example, I thought avoiding the use of air conditioners during the day in our flat was silly – why not just crank it down to 22º or so and be feelin' fine?

Well, one good reason was our electricity bill. Even if you’re running air conditioning mostly at night during the summer months, as the Talls now do, you can expect your bill to at least double. And if you add in running it all day in your living room – well, this is when you start hearing about people with electrical bills of several thousand dollars a month or more.

There’s also the environmental impact of using so much electricity. Hong Kong’s power plants run on coal, so the more electricity you use, the more air pollution you’re personally responsible for. Sorry to put it into such brute ugly terms, but if you’re worked up about global warming and air quality, shutting off your air conditioner is likely the best way – other than not owning a car – to reduce your ‘carbon footprint’ in Hong Kong.

So where are your limits? I’m pretty happy these days without aircon during the day at home – we turn it on now just on some of the hottest days – but Mrs Tall and I still can’t make it through the mid-summer without using it at night. MrB and family use theirs even less, I know – a target for us Talls to shoot for! But for many other expats, I know it’s tough to give it up.

Let me suggest several tactics I’ve found useful to help get by with as little air conditioning as possible in Hong Kong:

Fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans, fans </Monty Python ‘Spam Song’ voice>. Seriously, fans are your best weapon. Make sure every room in your flat has a fan set up and ready to go. If you have to move one into place, you’ll be far more likely to just reach for the aircon switch. Ceiling fans are also recommended wherever possible. Since most Hong Kong flats have relatively high ceilings, there’s usually room to install one, and they can make a significant difference in your comfort level. We’ve got them in both our living room and our bedroom, and they’ve made it possible for us to delay using our aircon by at least a month or two each spring.

At night, have a selection of different-weight blankets ready. This sounds kind of stupid and corny, but it’s surprisingly effective. In the past, I found the problem with the March-May and October-November seasons was temperature variability. Sure, one night it might be no problem skipping the aircon, but then a couple of days later it’d warm up, and suddenly the blanket that two nights ago was fine now felt leaden and oppressive. And getting up to go get another one was just too much trouble, so . . . .

So these days, Mrs Tall and I generally have blankets of at least two, and sometimes three, different weights ready to go during the ‘transitional’ seasons, from a light aircon quilt, to those fleece blankets you can get at Ikea, to the very thin cotton blankets that are almost like towels. Using the lightest possible blankets also allows you to set your thermostat higher when you do decide to turn on the aircon. For example, in past years when we used only an aircon quilt I needed to set the temperature at 23º to sleep comfortably; now, using cotton blankets, we usually get by at 25º.

Use sleeping mats. A traditional Chinese approach to sleeping cool in hot weather, such mats typically are made from split bamboo, or woven from fine rattan. These mats really do feel cool when you lie down on them, again allowing for a higher ambient sleeping temperature. We tried one of the woven ones a couple years ago, and threw it out after just a few months – it didn’t hold its shape, and frankly wasn’t that comfortable. It was also quite expensive – around HKD800. Now we’re using a much cheaper (~HKD100) split green bamboo one that’s working out just fine.

Buy furniture upholstered in leather. Yes, I know the typical Hong Kong ‘black leather sofa’ look comes in for lots of derision from hipper-than-thou expats. But you know what? Sitting on a leather sofa when it’s 27º in the room is lot more pleasant than sitting on a velvet-covered sofa, or one done up in any other fabric, for that matter. (For the record: we Talls have a leather sofa, but it’s not black.)

Buy a couple of dehumidifiers. In Hong Kong’s damp spring months it’s often not hot enough to warrant aircon, but it’s so humid you end up turning it on – usually at a very low temperature – just to dry out your bed sheets. One alternative is to turn on a dehumidifier in your bedroom for an hour or two before bedtime, then turn it off when you go to sleep and use a fan overnight. I find that a dehumidifier on all night leaves a room feeling stuffy and ‘airless’, but if you don’t mind that, it would be even more effective.

Turn on the aircon just long enough to cool the room. I know of a couple of people in Hong Kong who save on air conditioning by chilling down their bedrooms right before sleeping, then turning off the aircon and getting by with fans the rest of the night, as per the dehumidifier strategy above. This one doesn’t work for me – if it’s too hot to sleep without the aircon at bedtime, our bedroom gets right back to that level well before dawn – but why not try it out? Maybe your flat retains its temperature better than mine!

Readers, any other suggestions for beating the heat?


going to sleep wet & using fan

This is a technique that many HK people disapprove of, but which I found very useful during hot and humid months in New England and Illinois. Take a cool shower before you go to sleep (making sure to get your hair wet) and put the fan near the bed. I realize that men w/ less hair might find that the cooling benefits are less.

SK-baba tells that his father was very fond of the "hard pillow" head-rest (ceramic or wooden) when he was growing up. I don't think I could cope w/ that one.

If you live on a top floor, get a shade for the roof-top to cast shadows and reduce the heat pounding on your roof.

re: couch - we have a leather couch but usually have a cotton slip cover on it. However, we also make good use of the nice wooden floor to sit on.

Live in a cool place

Sound's obvious, but if you want to minimise aircon use it's worth keeping that in mind when you choose where to live. If the walls of your bedroom catch the mid- and late-afternoon sun, it'll be like trying to sleep in an oven.

So look for flats that face North, and are shaded by others on the South, West, and East. A good breeze helps too. Both flats we've lived in have had windows on opposite sides to let the wind through.

Finally, keep clothing to a minimum! I picked up a couple of pairs of very light summer shorts earlier this week. (American readers, shorts as in short pants, not as in Bart Simpson's "Eat my shorts" shorts). Bought in Yuen Long, they're a bargain at HK$10, and bright enough that I'll probably save on my lighting bills too.


PS SKmama's tip's a good one if you've got the hair, but keep it to yourself. If you tell local friends / family you're doing it, you're in for some serious um-chumming.

Wet hair

Wow -- if I tried that wet hair trick, Mrs Tall would escalate to Defcon 3, at least . . . .

I've seen those 'pillows' as well, but can't quite bring myself to try one yet.

Shades are a great idea, too. Our flat actually faces south, but is situated in between parts of buildings in such a way that we don't get too much direct sunlight during the day falling on our windows. But when we do, the shades go down -- it cuts a lot of the heat buildup.



Where you live

Actually, MrB, we've both ignored the most obvious 'beat the heat with location' tip: be rich enough to live on the Peak, which is noticeably cooler than sea level year-round! If only batgung.com paid well enough for both of us to make our dreams come true . . . .

Cooling down the room

Actually, we've started trying that this year and so far it has worked pretty well. We turn on the a/c for a couple of hours before going to bed, then turn it off and leave the fan and dehumidifier on all night. Actually, we leave the dehumidifiers on nearly all the time, and it is cheaper than having the a/c on all the time (once you get the humidity to the level you want, they cycle on and off through the days, generally--they do not run constantly). The house is much more comfortable and bearable with the humidity under control (plus, I really can't live with mold/mildew--my asthmatic son and I are allergic to these, and we would be in bad shape with humid rooms--BTDT).

With us it is dad2twoboys who has the problem with temperature, and he is making a conscious effort this spring to deal with the temp with a minimum of a/c.

our room is on the west side, and we keep the west facing blinds shut all afternoon (actually, keep the others shut in the morning--it does make a big difference--since I'm a homeschooling stay at home mom, we can open and close them throughout the day).

If the humidity level is livable, the a/c can go on for minimal time to deal with the temperature.


Wet T Shirt

A variation on this theme is to wear a wet t-shirt to bed and direct a fan at your torso. This was how I coped through a hot summer in Jersey City, NJ with no AC (4th floor, railroad, walkup).

beating the heat

another solution to beat the heat during the day is to walk in shopping centres all day, after all, how cheap is it to eat at the cafe de corals all around the city? :)only go home to sleep.thats what i did.

Keeping Cool during Summer

Same principle as the wet-hair but at least your pillow remains dry! Place a small moist face-flannel on your forehead/face as you go to bed.

Something I used to do as a kid during hot summer nights (mid70s) in UK as a kid. I guess we're spoilt now with aircon in every room in HK.


Apologies for going off topic but this is where I was sent to when I did a search for "dehumidifiers" on this site... Can I ask whether dehumidifiers really are a must in Hong Kong? The thing is that I've lived in Malaysia (which I tell people has Hong Kong's summer all year round) and Tanzania (whose coastal area weather is tropical) as well as Philadelphia (which can get pretty humid by cold climate standards) and never was told there that dehumidifiers were a must. So what's with Hong Kong and dehumidifiers?

P.S. Batgung, love your site. Find it really helpful, informative and often fun to read since moving to Hong Kong as well as when I was just fantasizing about doing so! :)


In eastern North America like Philadelphia, a dehumidifier is an important tool to reduce the humidity in the basement of a house making the heat/humidity more tolerable. More importantly, it reduces the growth of mold which can be harmful to human's respiratory system. Too much moisture is not good for the structural wood of the house.
Unless the interior of your apartment/condo is fairly separated from the outdoor air, operating a dehumidifier has limited benefit becasue moist air is constantly coming in replacing the drier air. Warehouses use them because they store valuable items that can be easily damaged by high humidity.
Many years ago I lived in HK without air-conditioner, but envied people who have it. Now I am not sure if it is a good thing to spend 2/3 of each day within a confined air-conditioned home, a humidifier may be.

Dehumidifiers, etc.

"In eastern North America like Philadelphia, a dehumidifier is an important tool to reduce the humidity in the basement of a house making the heat/humidity more tolerable."

Hmm, well, I lived in Philadelphia for close to 14 years -- in two different houses along with a couple of apartments -- and no one ever talked about dehumidifiers to me! And yes, those houses had basements but I noticed more that they were cool than humid...

"Unless the interior of your apartment/condo is fairly separated from the outdoor air, operating a dehumidifier has limited benefit becasue moist air is constantly coming in replacing the drier air."

Okay, this comment makes sense to me. So, in other words, forget about getting a dehumidifier?


Glad you commented YTSL.
I once lived not far from Philadelphia, about 40 minutes away in the Lehigh Valley where the summer humidity was just as torturous. Yes, the basements in these houses feel more cool than humid, but it is typically our first impression when walking down into it. High humidity is indeed also present. Some how, dehumidifier wasn't popular even in my time living there. But then I was only a graduate student there and my land-lady didn't know much about the subject, but excel in many other things.
In these houses, underground moisture seeps in through the walls of the basement and when they reach the fibreglas insulation, the latter becomes damp encouraging mold growth each summer. In terms of comfort, a drop of 10 percentage point in the relatively humidity, from say 85% to 75%, means you either enjoy your hot soup or sweat over it. The structural wood in the house don't like high humidity either, or the daily cycles of humidity change.
Knowing what a difference(s) a dehumidifier can make, I now always operate a dehumidifier in the basement, especially if I were to sleep in the basement.


> Can I ask whether dehumidifiers really are a must in Hong Kong?

As ex-HKer says, if the dehumidifier is going to do its job, you need the house sealed up. So if you're running it 24-hours, you'll need to keep doors & windows shut. You might need that if you're allergic to mold, or you have delicate furnishings / property you want to protect from high humidity. But I like the windows open so that doesn't work for me.

Mr Tall mentioned using it before going to sleep, just to take the damp feeling off the bedding. Not something I've tried, but sounds reasonable.

We were given one a couple of years back, and it has been in regular use for drying clothes. With two young children we are washing one or more loads each day, and in the dampest weather nothing dried fast enough. So now on those days the washing gets strung around one room, the door & windows are shut, and the dehumidifier is left running for several hours. Alternatively you could buy a tumble drier, or if you're using a local laundry, they'll dry it for you there.

So there could be good reasons you'd want to get a dehumidifier. But for the first 10+ years of living in Hong Kong I didn't own one, so no they're not a must.


PS Glad you like the site, thanks!

Love this site!

I live in Japan, I have never visited HK. I am constantly amazed at how much the advice and commentary on this site applies to my life here. This post, about beating the heat, has been especially useful. Today (July 5th) I decided that I could not stand the heat and humidity any longer, and finally switched on my AC. I don't like doing it, and I am going to leave the setting at 27 degrees Celsius for as long as I possibly can. BTW, have you the option of buying an energy saving AC unit? Mine also functions as a heater in winter (it gets pretty cold here!) and yet it only adds about US$100 to my annual power bill. Most people, even men, carry folding fans around outside. And many people sleep with gel icepacks under their necks. Your tips are very useful for me. Thank you!

A bit expensive in the short run...

Especially in high-rises in HK or pretty much any city, there's a lot of wind flowing by.  Has anyone invested in windmills?  They make very compact windmills that generate electricity and can be used to decreases your cooling costs and carbon footprints.  Solar panels can be used in conjuction wherever you get directly sunlight.

Both depend on how much direct contact you get.

Japan is fairly pro-eco, I don't know how HK is in that respect.