They usually need to be changed every 30 days or less. Pleated air filters are more expensive at first, but they are also more efficient at trapping particles. A general rule for pleated air filters (such as those manufactured by FilterBuy) is to replace the filter every 90 days. As the filter captures more dirt, dust, and allergens from the air, its efficiency decreases. In general, most air filter manufacturers and HVAC companies suggest changing the air filter every 90 days or 3 months.
This can vary depending on the location of your home (e.g. dry and dusty climates), if you have pets, and how old your system and equipment are. If you have pets in the house, you should consider changing the filter every 60 days or 2 months, and for homes with multiple pets or people with allergies or respiratory conditions, we recommend changing the filter every 20 to 45 days. Vacation homes or vacant homes that don't get much use can wait to change the filters every 9 to 12 months. The consensus is that the more you use your home, the more you'll need to change the air filter.
Some air filters are designed to last up to six months, while others need to be changed monthly. The denser the air filter, the longer it should last. In general, you can examine the thickness of the filter rather than the brand. You should also take a look at the MERV rating. In general, you should check the air filter once a month to see how dirty it is.
That's really the only way to know if your filter really needs to be changed. And if you or a family member has a history of allergies or asthma, plan to change the filter once a month, based on recommendations from medical associations, including the American Academy of Allergy, Asthma, and Immunology. Using an air filter with a MERV rating higher than that recommended by the manufacturer of your oven or air conditioner may affect its performance. But what happens if you let that time go by for a while? Before we talk about WHEN you should change your air filter, let's start with the WHY. Any use will cause a certain amount of dirt to be trapped in the air filter; after all, that's its job. Unfortunately, all the recommendations I can find are for 3 months, but I can't seem to find any recommendations for one-hour intervals.
If you changed the filter every 3 months, each filter would have very little use. However, it will put unwanted pressure on your climate system, leading to poor air quality and poor air circulation. If you have an asthmatic or allergic person at home, change the filter every 6 weeks to ensure optimal indoor air quality. If you have small children in the house, it's a good idea to use high-quality pleated air filters and change them as often as two months. My car recommends changing the dust and pollen filter (cabin air filter, which is equivalent to a domestic oven filter) every 15,000 miles if you drive in dusty or polluted conditions, which will be equivalent to 300 hours at an average of 80 km/h. If you live in a big city, pollutants such as smoke, dust, and other debris will seep inside and clog up your air filter at a much faster rate.
I also really like my washable electrostatic filters since they allow me to clean them for pennies whenever I want instead of having to worry about when to buy a 26% disposable filter.
