We've used these in our home for two years. They are AMAZING. After dealing with very bad allergies and mold in the south, we found out HEPA filters do NOTHING because they start to grow things on the filter, recycling bad odors and such over and over. This little machine has NO filter, NO maintenance. You buy it, plug it in, and forget about it. People came into our apartment and were shocked at the fact that you couldn't smell that anyone lives here. lol I also love that it's attacking the V.O.C.s from the paint and new construction we're in.