To change the filter on an in-wall air conditioner, a person needs to locate the air filter, take it out of the unit, and place a replacement in the unit. It is important to identify the filter type and size before purchasing a new filter.
The location of the air filter varies depending on the air conditioner unit. One common place to check is behind the main vent that blows cold air, which is often located near a thermostat. The air filter may be held in its housing with a set of fasteners, which need to be removed before the filter can be taken out. Some air conditioners may have an air filter in the furnace, which may be located behind a filter cap or a plastic or metal housing.
After removing the old filter, it is necessary to find an appropriate replacement. There are fiberglass, pleated and media filters. Fiberglass filters look similar to the screen in a window, but with a bigger frame. Pleated filters are roughly 1 inch wide and rectangular. Media filters are also rectangular and usually around 4 inches wide.
People who are not sure what kind of filter they have can bring it to a hardware or home goods store to compare it to new filters. This can be helpful to determine accurate sizing as well. The final step is to place the new filter where the old one used to be, paying careful attention to place it in facing the right way.