In a couple of weeks I'll moving to Far North Queensland in Australia, 16.9 degrees south, hot and humid. I'll be renting, and am wondering how to reduce my footprint when air con will be a necessity.

2 Answers 2


In the tropics, solar panels are very useful to reduce your carbon footprint. Since your energy consumption is dominated by air conditioning, and air conditioning need is largest during daytime, solar panel output correlates extremely well with your energy need.

Since you will live in a rental building, you probably can't install solar panels on your own roof. But maybe you could still own solar generation (indirectly). There are many companies that are in the business of generating electricity, and I'm sure in the tropics some of those companies are investing massively to solar production, because in the tropics it's the cheapest way currently to generate electricity. So if you buy enough many stocks of such an electricity company, you can claim that part of their production is your own, and that your electricity usage therefore is clean. That's what I do. I live so far in north, that solar panels don't make much sense, but wind power makes a lot of sense, as do nuclear and hydropower. So I invest in companies generating electricity with wind, nuclear and hydro.

The second important thing is to ensure that your air conditioning is as efficient as it can be. By far, the best air conditioner is a mini split unit. It's installed in such a manner that hole is drilled to the wall, and there are separate small outdoor and indoor units. Try to find a rental place that already has a mini split.

Of the permanent air conditioners, the second best is a window unit that doesn't have separate outdoor and indoor units so it's less efficient, but it's still better than the worst portable units.

If you have to use a portable air conditioner you yourself purchase because the rental place doesn't already have AC, the best is a portable mini split. It has separate outdoor and indoor units, and refrigerant lines between them. However, in very hot places you have to open a door slightly and carry the outdoor unit outdoors, so heat can leak. Also, you can use such a unit only at first floor or if you have a balcony.

The second best portable unit is a two duct portable unit. The entire unit is indoors, but it takes air outdoors from an inlet duct and expels it via another duct. Try to add an adapter to an open window that prevents air mixing and has holes for these two ducts.

By far, the worst portable unit is a single duct unit, since it's taking already cooled indoor air, heating it and blowing it outdoors, so it's expelling already cooled air (very inefficient), and replacement hot air has to come from somewhere. The worst way to use such a portable unit is to have an open window with duct hanging out there.

I use such portable units in the worst possible way in Finland. It's never so hot here that it would be a genuine problem. If you want to cool indoor air more than 5 Celsius degrees cooler than outdoor air, then a portable unit with duct hanging from an open window will probably not work. But it's never so hot there that I would have to suffer. The worst days have maybe 30 - 32 degrees Celsius outdoors.

You can make a single-duct portable unit slightly better by making an adapter to a window that has a hole for the duct. The replacement air has to come from somewhere, but you won't have much air mixing.

If you want an air conditioner that doesn't create noise pollution indoors, then a mini split is in practice a necessity.

  • Thank you, @juhist Lots of good info on air conditioners, it'll be interesting to see what sort the landlord will provide. I hope it'll be possible to remove humitdity from the indoor air. I've started to look into purchasing ownership in a sustainable energy provider.
    – MocBird
    Commented Dec 26, 2022 at 2:43
  • 1
    Every air conditioner will remove humidity, too.
    – juhist
    Commented Dec 26, 2022 at 8:40

The first piece of advice is to try to acclimatize to the hot weather as soon as possible - try to adapt to the environment. As time go on try to use the air conditioner less and less and the ceiling fans more and more and then try to use the fans less and less.

If possible try to live in a house that is elevated above the ground, one that is on stilts. Preferably one that offers good cross flow ventilation internally. Some older houses in the tropics can have partially louvered internal walls. This will help with cross flow ventilation.

One of the issues with modern houses in the tropics, built at ground level is they are closed up all day when people are at work. This causes heat to accumulate inside and when the occupants return home they return to a very hot house. One where both the air and contents (furniture etc.) are all hot. This includes the mattress on the bed and cooling that can take a long time. Sleeping on a hot mattress can be very uncomfortable.

Elevated houses, if done properly and securely, can be left open all day. Have a window open at each end of the house and leave all the internal doors open. This allows air to move throughout the house during the day and it won't be as hot as a closed house.

In terms of the mattress you sleep on. Consider a water bed with the water heater turned off. You may need to have a blanket, or similar, between the mattress and the sheet you lie on. Without one it may be too cold to sleep on such a large body of water, even in the tropics. If possible place the bed under a ceiling fan.

For uniform light conditions at night, a room with a ceiling fan needs to have sconce lights on the wall, no lights on the ceiling or the bottom of a rotating fan. Every fan wobbles.

In terms of heat from solar absorption a house painted in a lighter color than a darker color is better. Similarly, a house made of wood is better than one made of bricks, concrete or metal, because of the heat retention and radiation of different building materials.

A house that is shaded as much as possible: veranda, window shutters, shade cloths is better than one with no shading.

An abode with a well established jungle like garden with lots of shade will produce a cooler environment around the home than an empty garden or one with low height plants or one with no plants. Avoid concreted or paved pavements on the property, particularly large expanses such as wide driveways.

If you throw away food stuffs/scraps into the bin, freeze it and then when the bin is placed out for emptying put the frozen food waste in the bin. This will prevent the food from rotting in the bin and it will not attract insects and other animals. It will also prevent the bin from smelling of rotting food.

  • Some good hints in this answer. Freezing food scraps for example, when one doesn't have access to composting. Fans with lights are a bugbear in my present accommodation, I use side lamps.
    – MocBird
    Commented Dec 27, 2022 at 3:33

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