5 Best Portable Air Conditioners for Large Rooms (July 2025 Review UK)
Keeping a large room cool during hot spells isn’t always easy, especially if you’re relying on fans or smaller units that just don’t cut it. Portable air conditioners offer a simple way to bring the temperature down without the hassle of a full installation. The key is finding one that’s strong enough to handle the space without being too noisy or clunky to move around. In this guide, we’ve highlighted some of the most capable models currently on the market, with an eye on cooling power, energy use, and ease of setup.
1
Exceptional
NELGOLLE portable air conditioner for large room
What We Like
2
Exceptional
SereneLife 12000 BTU Air Conditioner
What We Like
3
Exceptional
Olimpia Splendid 10000 BTU Air Conditioner
What We Like
4
Exceptional
Pro Breeze 7000 BTU Air Conditioner
What We Like
5
Exceptional
BLU 9000 BTU Air Conditioner
What We Like
How to Choose a Portable Air Conditioner for a Large Room
Room Size and BTU Rating
Check the unit’s BTU rating. Larger rooms require more cooling power. As a general guide, 7,000 BTU suits rooms around 20 square metres, while units with over 10,000 BTU are better for spaces larger than 45 square metres.
Ventilation Requirements
All portable air conditioners need proper ventilation, usually through a window. Some come with a kit to make this easier. If the room has no windows, you’ll need to look at dual-hose models or consider a different cooling method.
Noise Levels
If you’re working, sleeping or watching TV in the room, the noise matters. Anything around 50 decibels or less is decent for home use. Higher-end models tend to be quieter, especially in sleep or eco mode.
Energy Efficiency
Portable air conditioners aren’t always cheap to run. Look for models with energy-saving modes, timers, or smart features that let you control them remotely. An A-rated energy label helps, but it’s how you use it that makes the biggest difference.
Do I need to drain water from my portable air conditioner?
In most cases, yes. As the unit cools the air, it also removes moisture. This water needs to go somewhere. Some models collect it in a tank that needs to be emptied every day or two. Others have continuous drainage through a small hose, and a few will evaporate the moisture automatically during the venting process.
Tips to Get the Best Out of Your Portable Air Conditioner
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Start it early. Don’t wait until the room is already roasting. Run it while the temperature is rising, not once it’s unbearable.
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Keep windows and doors closed. Portable ACs work best in sealed spaces. Open doors or gaps let the cool air escape quickly.
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Clean the filters often. Dirty filters reduce airflow and force the unit to work harder. A quick rinse every two weeks can keep things running smoothly.
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Use curtains or blinds. Blocking sunlight during the hottest part of the day helps the AC maintain a steady temperature.
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Don’t forget the drain. Many units collect moisture as they cool. Some models have a tank that needs emptying, while others drain automatically. Keep an eye on it in very humid weather.
