Split air conditioners have many advantages over normal air conditioners (so-called monoblocks). They are energy efficient, very quiet and can do more than just cool rooms. High-quality models can also heat or dehumidify an apartment or room.

By Sven Wernicke

Important: You should leave the installation of a split air conditioning system to a professional. Because the installation is very complex – especially when retrofitting. In the event of improper installation, climate-damaging refrigerant can escape. That being said, getting started in the world of split air conditioning is not complicated, nor is it very expensive.

What are split air conditioners and how do they work?

Split air conditioners such as the Bomann CL 6044 CB and the Kältebringer KB51 consist of two components: an indoor unit and an outdoor unit. They are connected to one or more hoses.

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The indoor unit is in the room you want to cool. This is the so-called heat exchanger. It draws in the warm room air and gives it to the refrigerant that circulates inside the unit. When the refrigerant heats up, it changes its physical state from liquid to gas.

The gas reaches the outdoor unit, which is located outside the building, for example on a terrace, a balcony or on the roof or on the house wall, via a refrigerant line. Here the gas is routed to the compressor. This cools the heated gas and the refrigerant liquefies again. The heat is conducted outside and the refrigerant flows back into the indoor unit, allowing the cycle to start over.

This means: A split air conditioning system does not cool the room air, but gradually extracts the heat from it. If a split air conditioner is to heat instead of cool, the entire process is reversed. The concept is comparable to that of a heat pump.

Recommended split air conditioners

Below are some recommended split air conditioners. As the technology becomes more sophisticated, the devices are no longer as expensive as they were a few years ago. And they now offer all sorts of comfort functions. Combination systems for cooling, heating and dehumidification are particularly popular.

Tip: Are you looking for a mobile split air conditioner? Unfortunately, there isn't. In this case, you should use a regular air conditioner.

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Bomann CL 6044 CB: Split air conditioner for smaller rooms

The recommended room size for the CL 6044 CB is 25 square meters. With the 4-in-1 air conditioning system, you can ensure a pleasant room climate in your living room, for example. Bomann promises an average noise level of 22 decibels in the interior – equivalent to a whisper.

The supplied infrared multifunction remote control is practical. The installation material for the specialist is included, as is a five-meter long refrigeration line for connecting the indoor and outdoor units.

The most important data :

• Split air conditioner for cooling, heating, ventilation and dehumidification
• Refrigerant: R32
• Cooling capacity: 9,000 BTU/hr
• Self-cleaning function, activated carbon filter for air purification
• Wall mount only

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Cold bringer KB34WH: With connection to the smart home

The name of the manufacturer says it all: the KB34WH from Kaltebringer cools rooms up to 55 square meters. If you attach great importance to a quiet split air conditioning system, you've come to the right place: In sleep mode, the cold bringer model reaches just 19 decibels.

A Wi-Fi module is already integrated for connection to the smart home and control via app. The device also supports the Alexa voice assistant and is compatible with Google Home. Mounting material, connection cable and a five-meter-long cooling line are included in the scope of delivery.

The most important data:

• Split air conditioner for cooling, heating and dehumidification
• Refrigerant: R32
• Cooling capacity: 12,000 BTU/hr
• Self-cleaning function, activated carbon filter for air purification
• Optionally with wall bracket or floor console

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Cold bringer KB51: Ideal for large rooms

With the KB51 you can cool large rooms up to almost 100 square meters. The dehumidification performance (1.5 liters per hour) is also impressive. The aforementioned KB34 model cannot keep up. Just like its sister model, the KB51 offers the particularly quiet sleep mode with 19 decibels.

The KB51 also supports WLAN for app control as well as Google Home and Alexa. A remote control is also included. Here, too, you will receive the necessary assembly and connection material for the specialist.

The most important data:

• Split air conditioner for cooling, dehumidification and heating
• Refrigerant: R32
• Cooling capacity: 18,000 BTU/hr
• Self-cleaning function, activated carbon filter for air purification
• Optionally with wall bracket or floor console

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Advantages of modern split air conditioners

Compared to traditional monobloc air conditioners, split air conditioners have many advantages:

• Significantly quieter as only the outdoor units produce noise
• Indoor units take up less space thanks to wall or ceiling mounting
• Much more efficient , thanks to intelligent cooling processes
• Less expensive to run because the higher efficiency saves electricity and therefore money
• Easier maintenance , for example when changing self-cleaning filters
• Optimal cooling and full control over the desired temperatures thanks to modern technology (sensors, smart home control)

What refrigerant do split air conditioners use?

The cooling gas R32 (difluoromethane), which is known for its good efficiency values, is now the most widespread. Other refrigerants are becoming less important, including the refrigerant gas R410A: It is more harmful to the climate than R32, but is still used in some systems. R410A could be banned in the coming years.

The climate-friendly refrigerant R290 (propane) is likely to gain in importance. Until then, R32 is the recommendation if you're thinking about buying a split air conditioner.

Coolants are a matter for professionals

The refrigerant in split air conditioning systems can severely pollute the climate if it escapes. That's why only experts are allowed to install split air conditioning systems and refill refrigerant. Certified specialist companies will also help you to choose a suitable location for a split air conditioner.

You should consider this when buying a split air conditioner

• Installation of the air conditioner: indoor and outdoor units of the split air conditioner usually have to be mounted on the wall, ceiling or floor. Check whether the installation is even possible for you. If you live for rent, you also need the permission of your landlord.
• Professional installation: When you buy a split air conditioning system, you have to prove that you have professional installation and maintenance carried out.
• Cooling capacity: how big is the room you want to cool? What performance is required for this? You should plan roughly 200 to 350 BTU/h per square meter to be cooled. Split air conditioning systems that are too powerful consume an unnecessary amount of energy, while those that are too weak are unable to cool a room properly. If in doubt, the specialist will also help to precisely calculate the necessary cooling capacity.
• Noise level: Even good split devices reach a certain noise level under full load, which is audible indoors. You should expect up to 55 decibels. This corresponds to the volume of rain or a soft conversation. If you are sensitive to noise, the values specified by the manufacturer should not be (significantly) higher.
• Other features: Many air conditioners offer intelligent control options via app or a connection to the smart home. This can be very useful. Almost all air conditioners have a timer and extensive temperature setting options. A quiet night mode may be useful – depending on where you operate the air conditioner.