Regularly changing your furnace air filter can improve the air quality within your home and improve your HVAC system’s efficiency. It is recommended that you change your air filter at least every three months. However, if you have pets if you smoke or if you have allergies filters should be changed more frequently. Before you purchase your replacement air filter you need to determine its location, the type, and the size replacement filter. You will need the most common location for air filters is between the furnace air handler and the return air vent. Some furnaces have filters inside the air handler and the least common location is at return air vents. The size measurement should be on the existing filter if they are not using a measuring tape to get the length width and depth of the filter. Be sure to write these down to make buying a new filter easy there are several different types of filters. The most popular is the 1-inch disposable filter either in lightweight or high efficiency for an even better quality filter. There are filters with hepa filtration and allergy reduction technologies these filters come in one inch as well as thicker two to four-inch versions less common types are electrostatic filters and reusable washable filters. When you’re ready to change your filter turn your thermostat to the off setting, remove the old air filter and be careful not to knock the dust off before inserting the new filter. Write the date on it for quick reference in the future insert the new air filter and make sure the arrows on the side of the filter are pointing in the direction that the air flows through the system. Make sure the filter is secured and then turn your thermostat back on.