Why can't I find the correct size furnace filter at my local home improvement store for my Trane Brand Equipment?

Filters for your Trane unit are made from higher-quality materials than those of the disposable filters found in retail stores. For that reason, replacement Trane filters can only be purchased through a Trane dealer. However, keep in mind that some Trane filters are reusable, and can be washed by hand in cold water.