Air conditioner

If you cool often or at night, take a split unit like the PortaSplit. It is quieter and uses less electricity because it releases the heat outside through the outdoor unit. If you only need cooling on a few hot days a year, a monoblock is enough. It is cheaper to buy and quick to set up. In return it is louder, and because it blows air from the room outside, warm air from outside flows back in. Stiftung Warentest sees it the same way. You can read why there's no monoblock here at the moment further down, in the question about how I chose the units.

Fixed split units are the quietest. According to the manufacturers, the indoor units of the test winners have only 19 decibels in their quietest mode. The PortaSplit is louder: according to the manufacturer it is 39 decibels in Silent mode, and in tests it was sometimes louder. Monoblocks are louder still, because everything stands in the room with them, including the compressor. Stiftung Warentest calls even the recommended monoblocks rather loud. The energy label shows the sound power: 59 decibels at the indoor unit of the PortaSplit, and 62 to 65 for the monoblocks that Stiftung Warentest recommends. For the bedroom, the sleep mode helps, or you cool it down before you go to bed.

That depends on how often and how long it runs. An example: if you cool for eight hours every day for a month, the PortaSplit uses about 100 to 140 kilowatt hours according to tests and the energy label. At 37 cents per kilowatt hour, the average in Germany, that is about €35 to €55. In the Que Choisir test, the monoblocks that Stiftung Warentest recommends used almost twice as much, so about €70 to €90 for the same month. In Austria and Switzerland electricity is somewhat cheaper. You only earn back the higher price of the PortaSplit through electricity after many years. In everyday life it matters more that it is quieter and does not pull warm air in from outside.

Yes, it works like a small heat pump and, according to the manufacturer, heats until it is minus 10 degrees outside. Stiftung Warentest only tested heating down to plus 2 degrees outside, though. So on cool days in spring and autumn you can warm single rooms with it.

They are the quietest and most economical and can help with heating in winter. At Stiftung Warentest (issue 6/2026) the Mitsubishi Electric MSZ-RZ25VU was test winner among the smaller units with 2.5 kilowatts, and the Samsung AR70F09CAAWN is the best-value tip. Among the larger ones with 3.5 kilowatts, the Daikin Perfera FTXM35A is ahead, tested in 2025. As a rough guide, Stiftung Warentest gives 2.5 kilowatts for about 25 square metres and 3.5 kilowatts for about 35. Only a certified specialist may install them, which is why you cannot order them here. It is best to get quotes early in the year, because once the first heatwave arrives the specialists are quickly booked up.

The PortaSplit here works with the refrigerant R32. Because of new EU rules it may no longer come onto the market new from 1 January 2027. But shops may keep selling units that are in the EU by the end of 2026. And if you have one, you may keep using it and have it repaired without restriction. Midea has announced a new PortaSplit with propane (R290) for 2027, which harms the climate much less.

You can usually just set up a monoblock, because you don't drill or change anything. For a fixed split unit, on the other hand, you need your landlord's consent, ideally in writing. That is because it needs a hole in the wall and an outdoor unit on the facade. With the PortaSplit it is not entirely clear: you don't drill anything, but the outdoor unit hangs outside. An expert from the German homeowners' association Haus & Grund thinks this is allowed in high summer even without consent, because it is not meant to be permanent. Still, it is best to ask your landlord beforehand. And be considerate of your neighbours, especially at night.

You may not simply put up a split unit with an outdoor unit; you first need a resolution of the owners' meeting. Since a ruling by the Federal Court of Justice in July 2026, however, owners are usually entitled to one. That applies as long as the unit doesn't disturb the others too much, for example with noise, and isn't an eyesore. For a monoblock you don't need a resolution, because you don't change anything. For the PortaSplit, it is best to ask the property management beforehand.

A portable unit is the easiest, because it only stands in your flat. If you want a fixed split unit, as a tenant you must notify your landlord beforehand. If they don't refuse within two months, under Austria's Tenancy Act that counts as consent. If they refuse, you rarely get further through the arbitration board or the courts. If you own a flat in a building with several owners, you need the consent of the others. Whether you also need a permit from the building authority depends on the unit, the noise and the location, for example in a protected zone. It is best to ask your municipality beforehand, in Vienna the building police. For portable units like the PortaSplit, according to the magazine profil, a permit is often not needed. But here too, ask your landlord first.

Portable units with a hose that you just plug in don't need a permit. In the canton of Zurich the cantonal government confirmed this explicitly. A fixed split unit, on the other hand, needs a building permit in most cantons, in Zurich usually for the outdoor unit. As a tenant you need the landlord's written consent for changes to the flat. For the PortaSplit I found no clear rule, because its outdoor unit only hangs on the window. So ask your property management beforehand and, if in doubt, the building office of your municipality. And one more thing: the units here have a plug that doesn't fit Swiss sockets. So I don't have a suitable offer for Switzerland right now, but I am looking for one.

For the split units I read the tests by Stiftung Warentest and also tests by home&smart, smarthomeassistent and mobiFlip. The PortaSplit was the only portable split unit in the Stiftung Warentest test, and I use it myself. Stiftung Warentest has not tested monoblocks itself for years. In 2026, however, it evaluated the big test by the French consumer magazine Que Choisir and recommended three units from it that are available in Germany. All three got the top mark for cooling there. On amazon.co.uk none of the three is available at the moment, which is why there is no monoblock here for now. I also compared the manufacturers' specifications and read tests by the British consumer magazine Which? and the Austrian consumer association VKI. None of these tests calls a monoblock really quiet, and I'd rather tell you that honestly.