Air conditioning unit for bedroom: Best portable air conditioner units and window kits for home

Britain’s summers are getting hotter, and sleepless nights during record-breaking heatwaves have consumers considering whether to invest in air conditioning for the bedroom.

Britain has “almost certainly” just lived through its hottest summer on record, according to provisional Met Office figures reported by BBC Weather.

The mean temperature across the UK was 16.13°C - well ahead of the previous record set in 2018, after a season marked by four separate heatwaves.

Temperatures peaked at 35.8°C in Kent in July, while Scotland logged its highest August temperature since 2003.

It hasn't been just the daytime highs making headlines. Long stretches of hot, dry weather have left homes stifling and hosepipe bans in force across much of England. For many households, the problem has not just been keeping cool outdoors but coping with restless nights in overheated bedrooms.

As climate change makes long, hot summers more likely, Britons are increasingly weighing up air conditioning as a practical home solution.

Here’s what you need to know about air conditioning units for bedrooms, and whether it’s really worth investing in air con in the UK.

Air conditioning unit for bedroom

Bedrooms are often the first place people consider cooling because a good night’s sleep is harder when temperatures stay above 20°C.

Portable air conditioners are popular as they can be moved around and used only in the room you need. If you choose to invest in an air conditioning unit for the bedroom you might want to look for units with a sleep mode to keep noise levels down.

Many portable models run at around 50–60 decibels - similar to background conversation - but 'quiet mode' settings can drop this by five–10 decibels, which makes a noticeable difference at night.

Units with a timer are useful so you can pre-cool the room before bed, then switch off automatically to save energy.

Since a typical portable AC can use 900–1,200 watts per hour, energy costs add up if they run continuously.

A 1,000-watt unit costs around 30p an hour to run on today’s electricity prices, meaning a few hours overnight is manageable for most households.

You can read more on the cost of air conditioning, including how much the different types cost to run, in our article.

Home air conditioning

Installing a permanent air conditioning system in your home can be costly, but it gives you consistent cooling and often doubles as a heater in winter.

Split systems (which consist of an indoor unit connected to an outdoor compressor) are the most effective, but they require professional installation.

A basic single-room split system usually starts at around £1,500 including installation, but larger multi-room or ducted systems can run upwards of £5,000.

On the plus side, modern systems are highly efficient: many come with an A++ energy rating and can reduce humidity, which is particularly useful in older UK homes.

Running costs can be as little as 10–15p per hour when used on an energy-saving mode, making them cheaper long-term than using multiple portable units.

Read more: Air conditioning cost: Best value brands and how much to run them

Portable air conditioner units

Portable units are the go-to choice for UK households.

They plug into a standard socket and usually come with a flexible hose to vent hot air out of a window or door.

Because they don't involve installation, they are a cheap option, although they do cost more to run than permanent fitted wall units.

Prices range from around £250 to £600 depending on power and features.

Cooling power is measured in BTU (British Thermal Units). For a typical UK double bedroom of 18m², experts recommend a unit of at least 7,000–9,000 BTU.

Larger living rooms might need 12,000 BTU or more. Many portable units now include extras such as dehumidifiers, remote controls and Wi-Fi connectivity for smartphone control.

The main downside is weight - many models weigh 20–30kg - but most come with wheels for easier movement.

Consumer reports show that during heatwaves, sales of portable AC units can rise by more than 200%, so buying early in the season avoids shortages and price spikes.

Mini air conditioner

These are compact devices often marketed as personal air coolers. They use water or ice to create a cooling effect, making them cheaper but less powerful than full AC units. They’re best for desks or small spaces rather than whole rooms.

Prices range from £30 to £100, making them accessible for households on a budget.

However, their cooling power is limited, usually dropping room temperatures by just 2–3°C in a small area, compared with 8–10°C from a standard AC. They also need regular refilling with water or ice packs, and in humid conditions they may add moisture rather than reduce it.

However, they can still act as a cost-effective relief for renters, students or home workers.

Air conditioner window kit

An air conditioner window kit is a cost-effective way to remove hot air from a room, without the need for intensive building works to install vents.

A well-fitted kit can improve efficiency by up to 30%, because it prevents cooled air from escaping. Without one, a portable AC will work much harder and cost more to run.

Window kits create a seal around the vent hose, stopping warm air from leaking back inside. DIY and universal options start from around £20.

Some kits use adjustable plastic panels, while others are fabric seals that can be cut to size. Tenants often prefer the fabric options as they don’t require drilling or permanent fixtures.

Wall hanging air conditioner units

Wall-mounted air conditioner units are more permanent than a portable model and give a sleeker finish. These are already common in offices and hotels, but are becoming more popular in homes.

They’re usually part of a split system and must be fitted by an engineer.

They offer the advantage of quiet operation and can also be positioned high on the wall to distribute air evenly, rather than blasting cold air at head height.

Modern designs are slimmer than older units, often just 20–25cm deep, making them more discreet. The main drawback is cost and the need for planning permission in listed buildings or flats, as the outdoor compressor has to be mounted on an external wall.

However, they are much cheaper to run than portable units, and generally have a longer lifespan, so may work out more cost-effective in the long run.

Repair air conditioning unit

Repairs for an air conditioning unit can be costly. Common issues include refrigerant leaks, broken fans or blocked filters. But suppliers suggest they should be serviced every year to prevent these problems or spot them early.

For portable units, it’s often cheaper to replace the model rather than repair.

Annual servicing usually costs between £100 and £150 for a split system and can help prevent bigger breakdowns.

Re-gassing (refilling refrigerant) can cost £150–£300, depending on the system. Portable units rarely justify repair, since spare parts are expensive and labour can exceed the original purchase price.

Regular maintenance such as cleaning filters and checking hoses for kinks helps prolong lifespan and efficiency. Most portable units last five to seven years with normal use, while a well-maintained wall unit can last 10 to 15 years.

Is it worth getting air conditioning in the UK?

Many people ask if it is worth getting air conditioning in the UK, especially when heatwaves are not a given every year.

It depends on your tolerance for heat, the type of property you live in and your budget. If you struggle with hot weather or have health conditions affected by high temperatures, air conditioning can make a big difference. For others, a combination of fans, blackout blinds and ventilation may be enough.

The UK used to have fewer than 5% of homes with air conditioning, but demand is rising sharply.

Sales of air conditioning units rose 2,420% at Sainsbury’s and Argos during the 2022 heatwave when temperatures hit 40C.

With summers becoming hotter and longer, air conditioning may become as standard as double glazing in new builds.

On the other hand, energy costs and environmental impact are major considerations. A single portable unit can add £30–£60 a month to summer electricity bills, depending on usage. For those worried about cost, hybrid solutions, such as using air conditioning only at night, could be a middle ground.

Do all portable air conditioners have to be vented out a window?

If you want proper cooling from your air conditioner, you will want to vent hot air out of a window.

Ventless portable units do exist, but these are really evaporative coolers, which only lower temperatures slightly. True portable air conditioners must push hot air outside, usually through a hose fitted into a window kit.

Without venting, the unit simply recirculates warm air and dehumidifies slightly.

Single-hose models are the most common, though dual-hose systems exist and tend to be more efficient as they draw in fresh air from outside. While venting through a window is easiest, some people use doors or wall vents.

The golden rule is that hot air must leave the room - otherwise, you’ll end up with a noisy, expensive fan.

How to cool a room without AC

If air conditioning isn’t for you, there are still ways to keep rooms comfortable:

Use blackout blinds or thermal curtains to block heat during the day.

Keep windows closed while it’s hotter outside than inside.

Use fans strategically, eg. point a fan outside a window to push hot air outside, or turn it inwards to draw in cooler air at night.

Place bowls of ice in front of fans for a DIY cooling effect.

Switch off electronics and lights that generate extra heat.

The Energy Saving Trust also recommends improving insulation - because not only does it stop the warmth escaping in winter, it stops the cooler air escaping during summer.

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