How loud is an air conditioner? Values for split and portable units

The noise level of an air conditioner is stated in the data sheet in decibels, or dB(A) for short. Two figures are usually given there, and they cannot be directly compared: sound pressure and sound power. Anyone comparing appliances should therefore always compare the same figure side by side, and for indoor units, also the same fan speed.

• Sound pressure level: the level reaching a measuring point at a specific distance from the device, i.e. roughly what you hear in the room. It depends on the distance: the further away you are from the device, the lower it is.
• Sound power level: the total amount of sound emitted by the appliance, regardless of distance. This value is shown on the EU energy label for air conditioners, separately for the indoor and outdoor units.

The sound power level is higher than the sound pressure level of the same unit. According to the data sheet, for the TCL VoxIN indoor unit with 9,000 BTU, the sound power level is 9 to 10 dB(A) higher than the sound pressure level for each fan speed; at the highest speed, this is 54 dB(A) compared to 44 dB(A). Two values that appear different can therefore describe the same unit.

Decibels are a logarithmic quantity. As a rule of thumb, the ear perceives 10 dB(A) more as roughly twice as loud. Small differences of 2 or 3 dB(A) are hardly noticeable in everyday life.

Data sheets specify one value per fan speed for indoor units. The online shop lists the sound pressure level of the quietest speed, which manufacturers often refer to as ‘Mute mode’. For the wall-mounted units in the range, this results in:

All sets are listed under split air conditioners. The two columns do not describe the same situation: the sound pressure level applies to the quietest fan speed and provides the best indication of how quiet a unit can be. The sound power level on the energy label for the TCL VoxIN corresponds to the highest fan speed according to the data sheet, not the quietest; it is suitable for comparing units with one another. Data as at: ACTEC product range, October 2026, wall-mounted units from the Hantech and TCL series; units for which the catalogue only specifies a value without a fan speed (up to 39 dB(A)) are not included. The values for individual units can be found on their respective product pages.

At full power, the same unit is significantly louder. The TCL VoxIN data sheet specifies 19 dB(A) in mute mode and 44 dB(A) at the highest setting for the 9,000 BTU indoor unit. The unit primarily requires this setting when cooling down a warm room; once the desired temperature has been reached, an inverter unit reduces its output and runs more quietly.

The outdoor unit houses the compressor and fan. It is therefore noisier than the indoor unit, but is located outside:

Information current as at: ACTEC product range, October 2026, outdoor units of split sets.

How loud the outdoor unit sounds at your bedroom window or on the neighbour’s property depends primarily on its installation location: the distance, walls that reflect sound, and the mounting. The relevant authority will inform you of the noise limits applicable at the property boundary and at neighbours’ windows; a specialist contractor can assist with planning the installation location. You can find out how to request certification from the specialist firm under ‘Professional installation of your air conditioner’.

In the case of a portable air conditioner with an exhaust hose, the compressor and fan are located in the room. According to the data sheet, the units in the range produce a sound pressure level of 51 to 54 dB(A) and a sound power level of 64 to 65 dB(A) – roughly the same as the outdoor unit of a split-system air conditioner, only inside the room.

Hantech’s mobile split units are quieter: with these, the compressor is housed in an outdoor unit outside the window; inside the room, the data sheets quote noise levels from 39 dB(A) on the quietest setting. For studies and living spaces where a fixed split unit is not feasible, this can be a good compromise. For details on what else distinguishes the two types of design, see ‘Monoblock or split air conditioner’.

• Compare like with like: sound pressure only with sound pressure, sound power only with sound power.
• Compare the same fan speed setting: the lowest value applies to the quietest setting. If you are cooling at full power even during the day, look at the highest value in the data sheet.
• Choose the right size: A unit that is suited to the room will reach the desired temperature and then reduce the output. One that is too small will run at high power for a long time. You can find out how to select the right capacity under ‘Which air conditioner for which room size?’.
• Bedroom: At night, the indoor unit operates on a quiet setting; a night mode further reduces the fan speed and temperature, provided the unit has this feature. What else matters there, from the right size to where the outdoor unit goes, is explained in Air conditioner in the bedroom.
• Multiple rooms: In a multi-split system, one outdoor unit supplies several indoor units; there is therefore one unit outside rather than several. These systems are listed under ‘Multi-split air conditioners’.

Dehumidifiers are also available. The products in the range specify a noise level of 46 to 53 dB(A) on their product pages; the largest unit, with a capacity of 30 litres per day, is the noisiest. They are listed under ‘Dehumidifiers’. Information on which unit is suitable for which room can be found under ‘Dehumidifiers for basements, flats and bedrooms’.