Which way does an air filter go in a furnace? On your new filter, find the arrow that indicates the proper air flow direction. This tends to confuse everyone more than anything else. That arrow must always face toward the furnace and away from the return duct that carries the air in need of heating or cooling
How often do you change your furnace filter? A four inch filter will need to be changed every two months and a five inch filter every three months. If you only have one animal then you can change that and change the filters every two, four and six months depending on the size of your filter. No animals means you can change every three, six and twelve months.
What is the best MERV rating for furnace filters? The Minimum Efficiency Reporting Value, or MERV, is a universal standard used to compare one furnace filter’s efficiency to another’s. When a furnace filter states a MERV, it usually refers to the E3 portion of MERV, which reports a filter’s success in capturing larger particles between 3 and 10 microns.
How to choose air filter? Disposable fiberglass – The most economical type of filter; they usually have a MERV rating of 2 or 3. These mostly just protect the furnace and keep it clean and don’t provide much in the way of air filtration.