Most manufacturers recommend changing 1-inch thick air filters every one to two months at a minimum, depending on your home’s indoor environment. If you have pets, a big family or are a smoker, you probably should change it monthly. The thicker, three to five inch filters used by newer high-efficiency furnaces need to be checked every 6 months. Most homes need them to be changed at that time, but some can actually last up to 12 months.
Filters are inexpensive and easy for most homeowners to change themselves. There are many benefits to frequently changing the filter. First, it can save you lots of money in energy costs. A clogged filter makes your furnace work much harder to push air through the ducts. Second, a filter that’s plugged with hair, dander, dust, bacteria and other junk will allow smaller particles to get through and into your home, lowering your air quality.
Don’t forget to change the filter in the summer, too. If the AC is running, air is moving through the filter and it will get clogged. That will result in higher energy consumption and less effective air conditioning.