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Should I buy an air conditioner?

By Matthew Knight

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Should I buy an air conditioner?

Do you really need an air conditioner? How much energy will it use? This guide will help you choose the best way to cool your home.

Portable air conditioner

The main types of gadget that can help your home feel cooler are air coolers, fans and air conditioners. This guide focuses on buying an air conditioner, where we answer your key questions - including whether air conditioners work, how much energy they use and if you actually need one. But below, we've outlined all three main types so we can help you choose the best for your needs.

What are the options for cooling my home?

Air coolers

Air coolers look a bit like dehumidifiers and are generally pretty portable. They draw in warm air and cool it using water that is stored in a tank. Air coolers don't require installation and do not need to be vented through a window like portable air conditioners. They are much less effective than air conditioners, however.

Key features to look out for are:

  • the size of the water tank - a larger tank means you'll need to refill it less often
  • a remote control to change your settings from a distance
  • ice packs to add to the water tank to making cooling more effective
  • handles and castors that make the air cooler easier to move.

Typical price: £69.99 - £119.99

Portable fans

Humble fans come in many shapes and sizes - they range from basic models right up to the expensive and very stylish Dyson Hot & Cool, which doubles as an electric heater. Fans use just a fraction of the energy that air conditioners guzzle, as they have to rotate just three blades. But they only move the air around - they don’t cool it - and their motor will generate heat while they do this.

Key features to look out for are:

  • different speed settings to control the flow of air
  • oscillation modes that move the fan from side to side
  • a remote control for ease of use.

Typical price: £15.00 - £250.00

Air conditioners

Air conditioners are more complex than fans and air coolers, using refrigerant to absorb heat from a room and cool the air. They tend to be much more expensive, too, and split-unit models require permanent installation.

Key features to look out for are:

  • sleep or night modes to keep noise to a minimum
  • timer options that allow you to set the machine to automatically switch on and off
  • a remote control to adjust settings without moving from your seat.

Typical price: £170.00 - £1,100.00

Find out more about the different types of air conditioner - see how to buy an air conditioner.

Do they really work?

They do cool you down. All the models we've tested over the years were able to lower the room temperature by several degrees, and were generally easy to set up and use. What does separate the poor air conditioners from the best is that the better models cool air more quickly and quietly.

All models offer a choice of settings for different conditions. On a cooler day, for example, you can use a fan-only setting to freshen your room. If the weather’s particularly sticky, you can take the moisture out by using the dehumidifier option.

So far, so good. But there are some downsides. The main annoyance is that they’re noisy, and portable models take up quite a bit of space. Fixed, split models are quieter, but need to be permanently installed.

The machines' electricity consumption is gluttonous compared with other appliances. Only one model we tested in our last test met its claimed A-rating for energy efficiency, with most others falling way short of the mark.

How do air conditioners work?

When switched on, air conditioners compress a refrigerant gas. It is then run through a series of coils to cool, and condenses into liquid. The liquid moves through an expansion valve, evaporating to create a cool gas which absorbs the heat from a room, cooling the air.

How much energy do they use?

The portable air conditioners we’ve tested used as much energy per hour as a typical fridge freezer uses in one day. In their defence, you’ll probably use them for only a few hours each day.

Could I rent one?

Yes. There are lots of companies that rent out portable air conditioners.

Trying a portable model out before you buy could save you a costly mistake. For instance, you may not realise how much noise they can make. At their quietest, they sound like a fridge on its cooling cycle. Some are really noisy, rattling and gurgling away. Renting can also show you how much room a portable model will take up in your home.

You can rent an air conditioner for just a couple of days or for longer periods of several weeks. Prices vary depending on the power and size of the one you hire, with prices typically starting from about £60 for week-long hire of a compact, lower-powered model, all the way up to £200+ for higher-powered units. The per-week price generally gets lower, the more weeks you sign up for.

Do I need an air conditioner?

If you're a healthy adult living in the UK, whether or not you buy an air conditioner really depends on how uncomfortable you find the temperature in your home, and how long uncomfortable heat tends to last for.

For most people, oppressive heat is rare and manageable enough that they choose to either put up with it, use natural methods of cooling (such as wearing cooler clothes, closing curtains and opening windows) or invest in a standard fan.

But for some, keeping cool isn’t a luxury - it’s a necessity. Babies sleep better in rooms no warmer than 20°C. Older people are also at risk of suffering poor health due to heat.

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