The most common problems with window and room air conditioners are: they don't cool sufficiently, they don't turn on at all, or they make noise.

These issues can be resolved by troubleshooting and repairing them. You might want to check out Buying the Best Window Air Conditioner or Room AC Unit if your window or room air conditioner is beyond repair.

The window air conditioner is not cooling

Room or Window AC not working may need to be recharged with refrigerant, but most likely they only need to be cleaned.

At least partially disassembling the air conditioner will be the first step in cleaning or repairing it. Partially or completely disassembling an item is shown in this video.

You can do this yourself or hire an air-conditioning or appliance repair professional. Consult your owner's manual before attempting the work and ensure you have the right skills and tools.

Using your air conditioner's make and model number, you can search for a manual online if you cannot find one.

A typical AC manual recommends the following:

1. Disconnect the unit from the wall or window and carefully remove it.  You should be able to remove the grille and the filter without uninstalling the air conditioner from the window if you only intend to clean the filter. There are many grilles that just pop off.
2. If you have to uninstall the unit to work on it, do so and put it on a sturdy work surface.
3. Remove the grille and filter and unscrew the metal cover (being careful not to damage the fins of the coil). The video above shows how to disassemble the air conditioner's cover completely.
4. Make sure the filter is thoroughly cleaned or replace it with a new one. You can easily replace an air conditioner filter online or at an appliance repair shop.
5. In this case, it's likely that the air conditioner's switch is faulty or that the thermostat needs to be cleaned or repaired.
6. For thermostat repair, refer to the owner's manual. This video shows a typical method of checking and clIf repairing the thermostat doesn’t solve the problem, unplug the unit and call an air conditioner repair person.eaning the air conditioner’s thermostat. 

Air Conditioner Makes Noise

An air conditioner that makes a lot of noise might have bad bearings, which is something an appliance repair person should handle.

Alternatively, you may be able to solve the problem with basic lubrication. For more information about oiling or replacing bearings,