Failure to replace HEPA Filters in air purifiers can cause dirty and moldy filters. This can result in harmful health effects including chronic illness, allergies, rashes, or other skin issues. This can also cause existing conditions to worsen. In order to maintain health benefits and purified air, it is important to keep up on regular HEPA Filter replacements. Fortunately, a HEPA Filter replacement in the Winix C535 Air Cleaner with PlasmaWave Technology is a simple process.