Quiet air conditioners: which portable units are really quiet
This article contains affiliate links (marked with *). If you buy through them, we earn a small commission at no extra cost to you. This does not influence our selection.
Contents
In short: Classic portable air conditioners (monoblock units) are never truly quiet, because the compressor and fan sit in the room with you. Even the quietest usually reach 50 to 60 dB in practice.
A portable split air conditioner such as the Midea PortaSplit is much quieter. Its compressor sits outside. Indoors, Midea states 39 dB(A) in silent mode, and a test measured around 50 dB. A permanently installed split system remains the quietest option.
What is the quietest air conditioner? The three types compared
| Type | Typical indoor noise | For a bedroom? | Notes |
|---|---|---|---|
| Monoblock (portable unit with exhaust hose) | Manufacturers: 45–55 dB in the quietest mode; often 55–65 dB in tests | only to a limited extent | affordable, no installation; warm air flows back in through the window gap |
| Portable split (e.g. Midea PortaSplit) | Manufacturer: 39 dB(A) in silent mode; test: approx. 50 dB | yes | outdoor unit on the window or balcony, no drilling, usually fine for renters |
| Split system (permanently installed) | good indoor units around 20–30 dB(A) in the quietest mode | yes, the best choice | needs a professional; renters need the landlord's consent |
Why dB figures for air conditioners are confusing
Two different figures are in circulation:
- Sound power level on the EU energy label: it describes how much sound the unit emits overall. For monoblock units it is usually around 63 to 65 dB(A).
- Sound pressure level in advertising: it describes what arrives at a distance of one metre, often in the lowest fan mode. That is why it is much lower, for example 43 or 50 dB.
Both figures are correct, but they cannot be compared. If a monoblock advertises “only 43 dB”, that almost always refers to the lowest setting. Cooling a room down on a hot day is noticeably louder. So always compare like with like: label with label, or measurement with measurement.
Our recommendation: Midea PortaSplit
The PortaSplit is a halfway solution. The indoor unit stands in the room, and the outdoor unit with the noisy compressor hangs on the window or stands on the balcony. A hose through a narrow window gap connects the two, with no drilling.
- Manufacturer figure indoors: 39 dB(A) in silent mode, 44 / 47 / 49 dB(A) on higher settings, measured at 1 m (Midea)
- Test measurement: about 50 dB in silent mode, just under 60 dB in boost (testsieger.de)
That is not whisper-quiet, but it is quieter than any monoblock and good enough for most people to sleep. Keep in mind that your neighbours can hear the outdoor unit. Use whisper mode at night, and consider a quick chat with them beforehand.
If it has to be a monoblock: what to look for
- Sleep or night mode: lowers the fan speed and adjusts the temperature gently. This matters more than any peak figure.
- Inverter compressor: runs steadily instead of constantly switching on and off. The repeated start-up is what disturbs most at night.
- Seal the exhaust hose: with a window seal the unit cools faster and spends less time on high.
- Pre-cool: cool the room on high in the evening while you are still awake, then only hold the temperature in sleep mode overnight.
- Distance and surface: do not place it right next to the bed. A rug or rubber mat underneath absorbs vibration.
Frequently asked questions
What is the quietest air conditioner for a bedroom?
A permanently installed split system. Without installation, a portable split unit such as the Midea PortaSplit is the quietest solution, because the compressor stays outside.
How loud can an air conditioner be at night?
For sleeping, most people find steady noise around 30 to 35 dB unobtrusive. Many also sleep well at 40 to 45 dB, especially with a steady sound without clicks and start-ups. Above that it gets difficult for light sleepers.
Are there quiet air conditioners without a hose?
Not for real cooling. Units without a hose are evaporative air coolers: they humidify the air and cool only slightly. They are quiet, but they do little against real heat in a top-floor flat.
Conclusion
If you want to sleep, get the noise out of the room, and only a unit with its compressor outside can do that. For renters, the Midea PortaSplit is currently the best quiet solution, while homeowners do best with a permanently installed split system. A monoblock remains the affordable stopgap: with sleep mode, well sealed and pre-cooled in the evening. The Amazon links lead to amazon.de.
Sources: Midea, testsieger.de, overview of typical monoblock values at temperaturheld.de. As of October 2026.
