The power of your air conditioner is very important. You need to think about whether you are cooling a single room, a selection of rooms or the entire house. If the air conditioner is too small you won’t cool down and you’ll waster electricity running it on high all the time. If, on the other hand, you choose an air conditioner that’s too large for your needs you’ll have to switch it off regularly when you become to cold. Switching it on and off all the time will also waste energy.

All air conditioners should have an energy-rating label which uses stars to rate the efficiency. The more stars the better. Also on the label will be an energy consumption box. The lower the numbers, the less it will cost to run. The one for cooling-only models has a blue band of stars and a blue box for the energy consumption figure. As the name implies, these air conditioners only have a cooling mode. The label for reverse-cycle models has two bands of stars. The blue band shows the efficiency when cooling, and the red band shows the efficiency when heating. There are also two energy consumption figures – blue for cooling and red for heating.

The fan in the air conditioner circulates the cool air around the room. Look out for air conditioners with a variety of airflow settings. While a high setting is good for cooling a room quickly, it can be quite noisy so you need to be able to adjust it to a lower level that keeps the room cool but quiet.

It may sound pedantic but you need to check how noisy your air conditioner will be. If it’s noisy, not only will it annoy you in your home but your neighbours may be affected too.

You should consider what the air conditioner will look like attached to your wall. Try to choose one that blends in with your décor.

A timer lets you switch your air conditioner at certain times even when you are not at home. This works well to cool the house down an hour or so before you arrive home.