In general, most air filter manufacturers and HVAC companies recommend changing the air filter every 90 days or 3 months. This may vary depending on the location of your home, if you have pets, and the age of your system and equipment. Pleated air filters are more expensive initially, but they are also more effective at trapping particles and can last up to 90 days, depending on usage. 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 will last. You can examine the thickness of the filter instead of the brand, and also take a look at the MERV rating. The ideal is to change your air filter every three months, however, there are certain factors to consider when determining when to replace an old filter. The frequency with which the engine air filter will need to be replaced varies from vehicle to vehicle.
Maintenance schedules for different vehicle brands differ in how often the air filter needs to be changed. On most Chevrolet engines, for example, the recommended change interval is every 45,000 miles, but Ford says it should be done every 30,000 miles on many of its engines. Hyundai also says every 30,000 miles, but shortens it to 15,000 for “severe driving conditions” such as heavy traffic in hot climates and frequent driving on unpaved roads or dusty conditions. These rules will apply to other brands as well.
If you drive in such conditions, it will often be necessary to replace the air filter before. Air filters trap pet hair, dust, and other irritating particles so that the air conditioning system returns fresh, clean air to your home. If you live in a mild climate and only use your air conditioner or heater for a few hours a day, a filter could last the entire season or up to an entire year. Air filters should be changed regularly in your home to keep the system running smoothly and maintain optimal air quality.
If you live in a big city, pollutants such as smoke, dust and other debris will seep inside and clog the air filter at a much faster rate. However, many homeowners are unaware of how often air filters need to be replaced, leaving their system vulnerable to damage. If you're a pet owner, you'll want to change the air filter every 2 months, especially when winter turns to spring and summer to fall. As a general rule, a lower occupancy of the home extends the life of the air filter, while a higher occupancy of the home reduces it.
Let's say there's a filter called “Fantastic Filter” and it can filter up to 40 gallons before it goes to waste. Regardless of the HVAC system you have, each unit needs a properly tuned quality filter to keep your indoor air quality clean and your unit running at peak efficiency. However, all filters have to get wet at some point due to the process which only explains why “the filters on the shelf can last a long time but once they are used they start to lose their properties”. If you live in a “smaller house” your air conditioners and ovens need to pump less air for the same amount of temperature change which could mean fewer filter changes.
The MERV rating is a scale from 1-20 which evaluates how well an air filter can remove particles from the air. If there is no smoker or pets in your home and your filter is the 1 filter that is commonly sold with a MERV rating of 4 you should be able to wait up to 90 days before changing it. Fiberglass air filters are more affordable but less efficient at capturing dust and particles in the air.