When it comes to a healthy ducted HVAC system, your air filter is absolutely essential. Not only do they improve the lifespan of your system, there are other benefits, too. Contrary to what many believe, the primary function of the filter is not to purify the air. An air filter will act as a barrier that will capture allergens, dust, and tiny particles from getting into the air you breathe inside your home. Keep in mind, the things you don’t want in your indoor air will build up on these lightweight filters over time.