Air conditioner buying guide

A home air conditioning unit is a cooling appliance that removes warm air from inside your home and replaces it with cooler, filtered air. It helps regulate temperature, reduce humidity, and improve indoor comfort, especially during heatwaves that are becoming more common across the UK.

There are two main types of air conditioning units, inbuilt and portable. Inbuilt systems are installed on walls or ceilings by professionals, whereas portable air cons can be easily moved where you are in the house as they have castors.

A portable air conditioning unit cools a room by pulling in warm air, removing the heat, and sending that heat outside through an exhaust hose. That’s why these units usually need to sit close to a window or another spot where the hose can vent outdoors. Many models also offer fan‑only and dehumidifier settings, which come in handy when the weather is muggy rather than hot.

Because the unit sits on wheels, you can simply move it to whichever room needs cooling the most. It’s a practical option for homes that only want to cool one space at a time without committing to a full air‑conditioning installation.

• Room size and BTU - When you’re comparing portable air conditioners, BTU (British Thermal Units) is one of the key things to look at. It tells you how much cooling power the unit has. Smaller rooms or bedrooms usually need around 7,000–9,000 BTU. Larger living areas or open‑plan spaces often benefit from 12,000 BTU or more. Choosing the right BTU rating helps the unit cool the room efficiently without wasting energy.
• Ventilation requirements - Portable air conditioners usually need external ventilation. Before buying, check where the hose will go and whether the room layout makes setup practical.
• Noise level - If you plan to use your air conditioning unit in a bedroom, noise level can make a difference, so it is worth checking the product details if quiet running is a priority for sleep or working from home.
• Fan-only mode - This setting circulates air without cooling, ideal for mild days. It’s a handy way to stay comfortable while saving energy.
• Heating mode - Some units can double as heaters during cooler months. This adds year‑round value if you want one appliance for multiple seasons.
• Dehumidifying mode - This mode is great for reducing moisture in damp or muggy rooms. It also helps improve comfort and prevents that sticky, humid feeling.
• Timer settings - Timers let you schedule when the unit turns on or off. Perfect for cooling before bedtime or saving energy during the day.
• Smart features - Some models connect to apps or voice assistants for easy control. They’re ideal if you like adjusting settings from your phone.
• Remote control - A remote lets you change temperature or mode from across the room. It’s a simple convenience that makes everyday use easier.
• Castors for moving between rooms - Wheels make it easy to roll the unit wherever you need cooling. Perfect for homes that only need to cool one room at a time.
• Where you will store it - Portable units can be moved when you need them, but they still need floor space and somewhere sensible to store the hose and window kit when not in use.

Getting the right BTU for your room size is important: too small and it'll work overtime without cooling properly; too large and you can end up with poor results and unnecessary energy use.

Use this as a simple starting guide: 

Rooms with big windows, south‑facing sunlight, or old/poor insulation often need a bit more cooling power. Spaces like conservatories and loft rooms heat up especially quickly, so choose a slightly higher BTU rating for those areas.

You’ll see the BTU rating listed clearly on each product page at Argos, making it easy to match the right unit to the size and layout of your room.

The main difference between the two really comes down to installation. A portable air conditioner is a simple, plug‑and‑play cooling appliance. Just unbox it, connect the exhaust hose to a window, and you’re ready to cool the room. A split air conditioning system is a more permanent setup, with an indoor unit mounted on the wall and pipework running to an outdoor condenser unit.

Here’s a quick comparison to help you weigh up the options and choose the best home air conditioning system for your space.

If you want flexibility and a lower upfront cost, go portable. If you're after quieter, more efficient cooling you'll use year-round, a split system could be a better investment over time.

Take a look at these useful tips to keep your air con running smoothly for years to come.

• Clean the air filters: Rinse the filters every couple of weeks to remove dust and keep the airflow strong. Make sure they’re fully dry before putting them back in.
• Empty the water tank: Most units collect moisture while cooling the space they're in, so emptying the tank regularly prevents shut‑offs and keeps the air fresh.
• Check the exhaust hose: Keep the hose straight and free from kinks so hot air can escape properly and the unit doesn’t have to work harder.
• Seal the window kit properly: Make sure there are no gaps around the window kit to stop warm air sneaking back into the room.
• Wipe down the exterior: Dust around the vents can build up, so a quick wipe with a soft cloth helps the unit pull in air more easily.
• Store it correctly in winter: Drain leftover water, clean the air filters, and coil the hose loosely before storing everything in a dry cupboard until next summer.

When you’re trying to stay comfortable in warm weather, you’ll usually come across air conditioners, air coolers, and fans. They all help you feel cooler, but they work in very different ways and the results vary a lot too.