05.How they work
Portable air conditioners work the same way as built-in systems: sucking in warm and humid air, cooling and dehumidifying it and blowing it back into the room.
The excess heat from the heat exchange is vented through an air duct that you install in an open window — a venting kit is included so you can seal the gap around the duct to stop the cool air escaping. Built-in models differ in that they have an external component to dispose of the hot air and condensed water they generate.
Portable models generate condensed water, which is collected inside them and needs to be emptied from time to time. With continuous use it could be necessary to empty them every two hours, otherwise the machines will automatically shut down. On top of that, some water drainage mechanisms may be difficult to use. The plugs may be difficult to reach because they’re located at the bottom rear of the units, and some may require a prying tool to lever them out.
It’s a good idea to inspect the controls, window ducting kits and water drainage systems of the different models in a shop. This will give you the best sense of whether you'll be able to tolerate the effort involved in setting up and running these machines.
Installation can be relatively simple. You need to adjust the length of the venting kit to fit your window (or sliding door opening - none of the ones tested will fit a sliding door opening, others may), connect the air duct to the air conditioner at one end and to the hole in the venting kit at the other, and then close the window onto the venting kit.
Some units expel the condensed water through a hose in the window kit, others collect it in a tank you need to empty. The manufacturer’s instructions should have all the details.
Do you need one?
Portable air conditioners are mostly ugly, noisy, high-maintenance and nowhere near as effective as their built-in counterparts. That said, they’ve improved a bit since our last test.
If you’re renting and don’t want to fork out for a fixed air conditioner, or you’re looking for one that can be wheeled from room to room, they may tick your box. Otherwise consider other cooling options first.
Also think about the size of the area you want to cool. If you have a large open-plan living area and kitchen, it’s unlikely one of these machines will have much impact other than as a personal cooling device.
- Before you buy anything, it’s a good idea to heatproof your home as much as possible. Even if you’re a renter, simple measures like sealing up all the gaps around your windows and doors and installing blinds or curtains over the inside of windows will help. You may then find that portable fans are enough. If you own your own home, you could look at installing external window shading or double-glazing your windows. This is something you can do without major rebuilding work. Roof insulation will also make a big difference.
- If you live in a dry climate, an evaporative cooler is a good cooling option, and is more energy-efficient than an air conditioner.
- If you live in a humid climate, built-in air conditioning will always cool and dehumidify a room more effectively and efficiently than a portable model with the same kilowatt capacity.
- But if you think a portable air conditioner is the only option in your situation, look for a model that delivers on its cooling promise and is easy to use.