Symptoms
- New or worsening noise from the unit when running
- May be a rattle, buzz, hum, or grinding sound
- Cooling performance may or may not be affected
Likely causes
- CommonLoose mounting or unstable window installationA unit that isn't firmly and levelly mounted can rattle against the window frame.
- CommonLoose internal panel or screwsVibration over time can loosen screws holding the cabinet together.
- PossibleDebris in the fan bladeSomething small caught in the fan can cause a repetitive tapping or rattling sound.
- PossibleWorn fan motor bearingsAging bearings can produce a grinding or squealing sound as the motor spins.
What to do
- Unplug the unit and check that it's firmly and evenly seated in the window frame, adjusting the mounting brackets if loose.
- With the unit unplugged, remove the front cover per the manual and check for visible debris near the fan blade.
- Check external screws and panels for looseness and tighten as needed.
- Plug the unit back in and listen closely to identify whether the noise is a rattle (mounting/panel) or a grind/squeal (motor).
- If it's a rattle from mounting, re-securing the unit usually resolves it.
- If it's a grinding or squealing sound, this points to the fan motor and is often not worth repairing on an older unit.
Tools and parts
- Screwdriver
When to call a pro
A grinding or squealing motor is often not economical to repair on a window unit; replacement is usually the practical choice.
Safety
Use caution
Always unplug the unit before opening the cover or reaching near the fan blade.