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Should I buy an air conditioner?

By Aaron West

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Should I buy an air conditioner?

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

Only 8% of Which? members own a standalone air conditioner. But with hotter summers becoming the norm, that number could be set to increase – so do you need one?

In this article

Do I really need an air conditioner? 

According to our survey, the main reason people owned a standalone air conditioner was to make it easier for them or their partner to sleep. For example, you might work night shifts and have to sleep during the day, when temperatures will be higher. Or you might simply struggle to sleep at night when it's hot and find it difficult to cope with the sleep deprivation.

Other reasons included owning one for health reasons. Babies sleep better in rooms no warmer than 20°C, for example, and older people are also at risk of suffering poor health due to heat.

Another popular reason people bought an air conditioner was to cool their conservatory. And no wonder, with a glass roof and walls, these could easily get up to sweltering temperatures in summer.

On the flip-side of that, most people have never felt the need to invest in air conditioning. The UK climate doesn’t call for it most of the time, and air conditioners are usually expensive.

Why don't you own an air conditioner?

Of the 92% in our survey who don't own a standalone air conditioner, by far the most popular reasons was simply not feeling the need to have one – either due to not having the need to use it often enough, or by having an electric fan.

Other reasons included the high up-front costs and running costs, as well as the environmental implications of the high energy consumption.

Another obstacle that stopped 3% of people, and is worth considering, is storage space. Air conditioners are large, with most being about the size of an under-counter fridge. So it’s worth planning where you would keep it in summer, and when not in use.

How to buy an air conditioner 

Air conditioners use a refrigerant to absorb heat from a room and cool the air, rather than just blowing it around. This is why they tend to be much more expensive than other options - such as an electric fan. But they also tend to do the best job.

Standalone or portable air conditioners generally start from about £200. A split-unit model will cost you more, upwards of £500, not including installation fees.

Key air conditioner 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
  • extra modes and uses, such as dehumidifying, or electric fan heater modes
  • air filters to help purify the air as it cools.

Find out more about the different types of air conditioner and read our first look reviews on how to buy an air conditioner.

What other options are there 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.

Typical price: £70 to £120

Air cooler features to look out for:

  • the size of the water tank - a larger tank means you'll need to refill it less often
  • a remote control to change the 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.

Portable fans

Humble fans come in many shapes and sizes - they range from basic models right up to the expensive and multi-functional Dyson Hot & Cool, which doubles as an electric heater. 

Fans use just a fraction of the energy that air conditioners guzzle, as they only have to rotate lightweight blades. But they only move the air around, which will help your room feel fresh and less muggy, rather than actually cool it.

Typical price: £15 to £250

Portable fan features to look out for:

  • a range of 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.

Stuff you can do yourself

There are a few useful habits you can form to help control the temperature of your home, or to simply cool yourself down in hot weather. 

Typical price: free

Top tips for keeping cool:

  • Close the curtains when the sun is facing them.
  • Open the windows on either side of the house to allow air to flow through.
  • If you own a conservatory, keep the door between it and your house closed, as a lot of heat will leak from it.
  • Spray cold water on yourself and allow it to evaporate.
  • Have a cold drink.

Do air conditioners really work? 

Put simply, yes, they do cool you and the room.

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 separates poor air conditioners from the best is how quickly and quietly they work, and how energy efficient they are.

Most models will offer a choice of settings for different conditions. On a cooler day, for example, you can use a fan-only setting to help freshen up your room. If the weather’s particularly sticky one day, you can use the dehumidifier option to make it less humid.

But there are some downsides. The main annoyance is that they’re noisy and energy hungry, and portable models take up quite a bit of space. Fixed, split models are quieter and more efficient, but need to be permanently installed in just one room.

How much energy do air conditioners use? 

The portable air conditioners we’ve tested in the past 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 – but this can still easily add up.

The energy efficiency of an air conditioner is usually measured by its energy efficiency ratio (EER). This is the ratio between the cooling capacity, in British thermal units per hour (BTU), and the power input, in watts. Generally the higher the EER, the more energy efficient the air conditioner, although the actual BTU delivered by a machine can vary.

Is air conditioning bad for the environment? 

Air conditioners are said to be bad for the environment for two key reasons: the refrigerants used in them and their high energy consumption.

Refrigerants are liquids used in air conditioning and refrigeration to actually absorb the heat. One common refrigerant in air conditioners, hydrofluorocarbons (HFCs), traps thousands of times as much heat as carbon dioxide. 

If your air conditioner is working properly, it shouldn’t release HFCs into the atmosphere. But some HFCs are released during the manufacturing process, if your air conditioner has a leak, and when you dispose of it.

Air conditioners also take a lot of electricity to run. As global climate change increases, and UK summers get hotter and longer, there will be growing demand for air conditioning, leading to higher electricity consumption. This in turn will increase the amount of fossil fuels burned, increasing the rate of climate change, and therefore increasing the demand for air conditioners. So it can easily grow to be a vicious cycle.

Can you hire or rent an air conditioner? 

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

Trying out a portable model 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 space a portable model will take up in your home.

Rental prices typically start from about £60 per week for a compact, lower-powered model, all the way up to £200+ for higher-powered units. As such, if you plan on using it for more than 4 weeks, buying would be a better option, if you have the storage space.

*Online survey: 1,470 Which? members in June 2018.