While there are certainly topics that require you to know more, the business of air purifiers and hepa air purifiers can be a bit confusing. If you have allergies, asthma or indoor odor problems and your air quality is at risk, getting buying a true hepa air purifier is probably a good idea. There are of course all kinds of different brands and models with different features and capabilities; I will suggest you look out for a few of the following things. Avoid units that are very cheap. This should go without saying, but you get what you pay for. Secondly, make sure that the unit is labeled as a true hepa air purifier and not some knock off that just uses the word “hepa” as a marketing trick. I would look for a hepa air purifier that can cover a large amount of square footage, also known as the “area” you are looking to purify. Look for units that can clean at least 300 square feet. A long filter life is also desirable as maintenance costs can add up a bit when having to replace hepa air filters often. Good luck on your search.