Window Air Conditioners and Noise:

An often overlooked part of selecting a window air conditioner is noise.  Many window air conditioners are put into commonly inhabited room like a living room or bedroom.  Having a noisy unit while trying to watch tv or sleep can be quite annoying.

Most window air conditioners range in noise level from 47-63 dB.  The chart below compares the levels of window ac noise to some more common sources of noise for reference.  For ease of comparison the noise levels were broken into 3 ranges (low, med, and high).  These ranges are intended to represent the three airflow ranges that are selectable on most common window air conditioners.  These ranges are generalized, when making comparison about specific window air conditioners the manufacturer data should be reviewed.

The discussion below will help to properly understand sound levels in dB.  Decibels (dB) are not a linear unit.  The decibel is a logarithmic unit and thus the sound pressure scales up quite quickly for small changes in dB.  Generally, for sound pressure data a distance needs to be given as this has an effect.  Typically, this data is not provided with the sound pressure numbers on the manufacturer data sheet.  One can assume that all data is given at the distance of a couple meters.

The dB is a calculation of the ratio of sound pressure levels between a source P1 and a reference source P0.

When the sound pressure of the source P1 is twice as powerful as the reference P0 the dB difference is equal to 3 dB.  So, a 3dB difference on the above chart represents a doubling of sound pressure.

When the sound pressure of the source P1 is ten times as powerful as the reference P0 the dB difference is equal to 10 dB.  So, a 10 dB difference on the above chart represents a ten times level of sound pressure.

This is why it is very important to buy a quiet window air conditioning unit.  A 47 dB window ac unit is much quieter than a 63 dB window ac unit.  The sound levels that the manufacturer's produce for data sheets are certainly under optimal conditions.  Improper installation and other factors can lead to a window ac unit being much louder than it needs to be.  Below are some tips for achieving quiet operation from an air conditioning unit.

Tips for Reducing Window Air Conditioner Noise:

Vibration from installation:

Place your hand on several areas on the window air conditioner and window while the unit is operating.  If hand placement attenuates the noise the installation may be suffering from vibration noise.  Re-install the foam between the window pane and the window unit or try some other methods to relieve the vibration.

Front Panel:

Sometimes, the front panel will not be securely fastened or not capable of securing well enough to rid vibration.  Make sure that the front access panel is not vibrating and causing noise.  Adding gasketing or tape to keep the panel secure can get rid of this source of noise.

Air Filter:

Keep the air filter clean.  The extra pressure drop due to a dirty clogged air filter can lead to extra noise as the air passes through the filter.  The filter will make the least amount of noise when it is clean and provides the least amount of pressure drop.  This will also make the unit run more efficiently and provide more cooling.

Fan Blades:

Bent fan blades can lead to vibration.  When a fan blade is out of balance it causes vibration as it rotates.  Only try this type of repair if you are very comfortable working on mechanical/electrical components safely.  If you suspect this is a problem unplug the unit and gain access to the fans.  Spin the fan with your hand and visually see if it is spinning properly.  If it appears out of balance or bent bend and try again.