What is Split System and How it works
The most common type of air conditioners is a split-system. At the moment it is a standard of air conditioning all over the world, that is why the device, which is called “air conditioner” in the household, is called a split-system by specialists.
Those, who have not installed air conditioner in the house or office before, having heard this term, naturally ask a question: what is a split-system and why this type of air conditioner is the most common?
Split-system is a construction type of air-conditioner, which consists of two blocks: inside and outside. The split-system got its name from the English word split, which means to divide, to separate into parts. In split-system air-conditioner functions are divided between two blocks.
In order to understand correctly, what split-system is, let’s get acquainted with the principle of work of such appliance. Any air-conditioner works due to the property of liquids to change its state when the pressure is changing and to absorb or emit thermal energy at that.
Special liquid – refrigerant, circulating between internal and external blocks of split-system, is easily taking heat, turning into gas and giving it away efficiently by condensation process. By constantly circulating between the units of the split system, the refrigerant in this way transfers the heat from the apartment to the outside, while the external and internal fans help dissipate this heat with their respective units.
The process involves a compressor and a thermostatic expansion valve, which, working in tandem, change the pressure of the refrigerant as it passes between the units in order to ensure that heat is exchanged and the desired temperature inside is reached.
Thus, the outdoor unit is a compressor and condenser unit, where the heat extracted from the room by the indoor unit is released in cooling mode.
The indoor air conditioner unit is the so-called evaporator, where the refrigerant cooled in the outdoor unit enters, giving its cold inside the room. This cools the air inside, after which the heated refrigerant enters the outer unit again, where it is cooled.
The split system units are connected to each other by copper tubes through which the refrigerant circulates, and by electrical control cables. Modern split-systems can usually also work in heating mode, then the indoor and outdoor units swap functions.
The split system is the most versatile type of cooling system: it is widely used both in residential areas and in offices, shopping centers and other types of buildings.
Best 2kW split system air conditioner units
For the very small split system air conditioning units, the top two energy-efficient Mitsubishi Electric models are also the lowest in price. They are affordable and great value for money. The Daikin and Panasonic model is less energy efficient, but much higher in price. Fujitsu offers a great value cooling the only model for around half the price of the top Mitsubishi Electric models.
| Brand | Model No | Cool Stars | Cool Output (kW) | Heat Stars | Heat Output (kW) | Purchase Price |
| MitsubishiElectric | SRK20ZSXA-W | 7.0 | 2 | 7.0 | 2.70 | $445 |
| MitsubishiElectric | SRK20ZMXA-S | 6.0 | 2 | 5.5 | 2.5 | $457 |
| Fujitsu | ASTG07CMCA/AOTG07CMCA | 5.5 | 2.10 | $240 | ||
| MitsubishiElectric | DXK06ZSA-W | 5 | 2 | 5 | 2.7 | $554 |
| Daikin | FTXM20P/RXM20P | 5 | 2 | $234 | ||
| Panasonic | CS-Z7RKR/CU-Z7RKR | 5 | 2.05 | 5 | 2.7 | $548 |
| Daikin | FTXM20P/RXM20P | 5 | 2 | 5 | 2.70 | $571 |
Best 2 to 2.5 kW split system air conditioners
For small split systems, the Daikin model comes out on top. It has an amazing 7 star energy efficiency rating and a lower purchase price than all the other brands. The other brands offer their top models with less energy efficiency and a higher purchase price.
| Brand | Model No | Cool Stars | Cool output (kW) | Heat Stars | Heat Output (kW) | Purchase price |
| Daikin | US7 FTXZ25NV1B/RXZ25NV1B | 7 | 2.5 | 7 | 3.5 | $594 |
| Daikin | FFA25A2/RXS25L3 | 5.5 | 2.5 | 3 | 3.2 | $777 |
| Samsung | AR09KSWSWKN | 5 | 2.5 | 5 | 3.2 | $625 |
| Mitsubishi | MSZ-GL25VGD/MUZ-GL25VGD | 5.5 | 2.5 | 5 | 3.2 | $657 |
| Panasonic | CS-Z25TKR/CU-Z25TKR | 5 | 2.5 | 5.5 | 3.2 | $640 |
| Fujitsu | ASTG09KNCB/AOTG09KMCB | 5.0 | 2.5 | 5 | 3.2 | $662 |
Best 3.5 kW split system air conditioners
With the small/medium split system air conditioning units, Daikin again comes out on top for the best value for money. Its model holds an energy efficiency of 5.5 stars and a purchase price, similar to the other brands. The other brands however offer a lower energy efficiency rating score. Interestingly, the Samsung model was the least energy efficient with 3 stars and had the highest purchase price.
| Brand | Model No | Cool Stars | Cool output (kW) | Heat Stars | Heat output (kW) | Purchase price |
| Daikin | FTXZ35N/RXZ35N | 5.5 | 3.5 | 5.5 | 5 | $954 |
| Panasonic | CS-RZ12RKR/CU-RZ12RKR | 4 | 3.5 | 5 | 3.7 | 891/457 |
| Panasonic | CS-Z35TKR/CU-Z35TKR | 4 | 3.5 | 3.5 | 4.3 | $994 |
| Mitsubishi | SRK35ZSA-W | 4 | 3.5 | 4.5 | 3.7 | $931 |
| Daikin | FTXM35P/RKM35P | 3.5 | 3.5 | 5 | 3.7 | $954 |
| Fujitsu | ASTG12KMCB/AOTG12KMCB | 3.5 | 3.5 | 4.5 | 3.7 | $954/491 |
| Mitsubishi | MSZ-FH35VE-A | 3.5 | 3.5 | 5 | 4.00 | $948 |
| Samsung | AR12KSFSAWKN/AR12KSFSAWKX | 3 | 3.5 | 3.5 | 4.00 | $1039 |
Best 5 kW split system air conditioners
In the medium split system unit range, Panasonic, Daikin and Mitsubishi Electric all had models with the same energy efficiency rating of 4 stars and a similar purchase price. Samsung again reflected the worst value for money, with two of its models having extremely low energy star ratings and high purchase prices.
| Brand | Model No | Cool Stars | Cool Output (kW) | Heat Stars | Heat Output (kW) | Purchase price |
| Panasonic | CS-RZ18RKR | 4 | 5 | 4. | 6 | 1456 |
| Daikin | FTXM50P/RXM50P | 4 | 5 | 4 | 6 | $1485 |
| MitsubishiElectric | MSZ-GL50VGD/MUZ-GL50VGD | 4 | 4.8 | 3.5 | 5.8 | $1450/714 |
| Fujitsu | ASTG18KMCA/AOTG18KMCA | 3.5 | 5 | 3.5 | 6 | $1507/697 |
| Samsung | AR18KSFSAWKN/AR18KSFAWKX | 2.5 | 5 | 3 | 6 | $1622 |
| Samsung | AR18KSFTAWQN/AR18KSFTAWQX | 2 | 5 | 2.5 | 6 | $1804 |
Best 7kW+ split system air conditioners
In the large air conditioner group, all of the five brands had a model with a 3 star energy efficiency rating. All also had a similar purchase price except for Samsung, which again had a much higher purchase price. Samsung also has another model with a 2 star rating, with the highest purchase price than all of the other models listed.
| Brand | Model No | Cool Stars | Cool Output (kW) | Heat Stars | Heat Output (kW) | Purchase price |
| Samsung | AC071KN4PEH/AC071KXAPEH | 3 | 7.1 | 3 | 8 | 2238 |
| Fujitsu | ASTG22KMCA | 3 | 6 | 3.5 | 7.2 | $1919 |
| Panasonic | CS-Z21RKR/CU-Z21RKR | 3 | 6 | 3.5 | 7.2 | $1919 |
| Daikin | FTXM60P/RKM60P | 3 | 6 | 3.5 | 7 | $1867 |
| Daikin | FTXM60P/RKM60P | 3 | 6 | $885 | ||
| MitsubishiElectric | MSZ-GL60VGD/MUZ-GL60VGD | 3 | 6 | 3.5 | 6.8 | $1861 |
| Fujitsu | ASTG24KMCA/AOTG24KMCA | 2.5 | 7.1 | 3 | 8 | $2358 |
| Daikin | FTKM71Q/RKM71Q | 2.5 | 7.10 | 3.5 | 8.1 | $2233 |
| Samsung | AR24KSFSAWKN/AR24KSFSAWKX | 2 | 7.1 | 2 | 8 | $2518 |
Best 9kW+ split system air conditioners
For extra large units, Panasonic has the highest energy efficiency rating with 3.5 stars and the lowest purchase price, offering value for money. Samsung again had one of the highest purchase prices, alongside Fujitsu.
| Brand | Model No | Cool Stars | Cool Output (kW) | Heat Stars | Heat Output (kW) | Purchase price |
| Panasonic | S-100PU2E5A/U-100PE1R5A | 3.5 | 10 | 4.5 | 11.20 | $2615 |
| Samsung | AC100KN4PEH/AC100KXAPEH | 3 | 10 | 3.5 | 11.20 | $3078 |
| Mitsubishi | SRK95ZRA-W/SRC95ZRA-W | 2.5 | 9.5kW | 3 stars | 10.3kW | $2895 |
| Fujitsu | AUTA36LCLU/AOTA36CTL | 2.0 | 10.00 | 2.5 | 11.20 | $3380 |