Ans - I would say that your chimney cleaner will be able to give you more of an accurate answer to that question. Filterless chimneys can have deposits built upon them, and filterless chimneys are unable to catch the most dangerous particles-mercury, soot, tar, heavy metals, or bacteria. It's much better to just get a system with filters. You'll sleep better at night knowing it is doing what it's supposed to do-protecting you and your family from these pollutants in the air. I hope this information helps! If you have any additional questions please feel free to ask and hopefully someone on