A clean air filter is integral to a properly functioning HVAC system, but knowing how to get the right one isn't always easy. Not all filters or systems are created equal, so you can’t buy any filter, but you can check part numbers on the filter itself for the proper sizes. Once you have the size you need, consider what you want out of a filter. Air filters can affect the quality of air in your home, including allergens and particulates, and they can even help remove certain odors like cigarette smoke. A 3M air filter, for instance, can help fend off dust and smog coming in from outside. Next, consider the function that the air filter's supposed to serve. Regular flat fiberglass filters are designed to trap particles in the air, but that's all-- these filters are chiefly designed to protect an HVAC system’s internals from dust and debris building up. You'll want a filter with a relatively high minimum efficiency reporting value (MERV) rating, but filters with ratings over 14 are generally overkill for a regular home. Pleated filters tend to be the best choice if you need something for air quality, and carbon filters also help to trap and capture particulates. 3M Filtrete products have been recommended as a solution to allergy headaches, for instance, as they block the particles that cause the buildup of pressure. Indoor air is generally far more polluted than outdoor air, but good air filters can help. By ordering the right type of filters for your HVAC system, you can maintain the best possible air quality for yourself and your family. Your Filter Connection sells 3M furnace filters online, and ships to anywhere in the continental United States.