When it comes to air filters, size matters. The difference between a 20x20x4 air filter and a 20x25x4 air filter is the thickness of the filter. The 20x25x4 air filter is thicker than other air filters, with a thickness of four inches. This offers greater surface area to capture more particles and germs from the airflow, making it more effective and longer-lasting than other disposable air filters.
Using a 4-inch-thick air filter for a system that's made for a 1-inch-thick filter will actually reduce efficiency. Washable filters should be rinsed with a garden hose once a month, air-dried and put back in place. The table below shows standard size 1, 2, and 4 inch deep air conditioning filters for your air conditioner, furnace, HVAC, and atomic filters. The 4-inch thick air filter has an advantage over the 1-inch filter in terms of longevity, airflow, and maximum filtering potential. To enjoy the benefits of using 20x25x4 air filters, the heating and air conditioning must work regularly.
Most HVAC technicians recommend changing 1-inch air filters every 30 days, while 4-inch filters can be changed every 3 to 6 months. The MERV (minimum efficiency report value) is a rating that indicates how well an air filter can collect particulates from your home air. If improving air quality is a priority for you, filter depth doesn't matter as much as MERV. Compared to the cheapest basic filters available, medium-efficiency MERV filters can significantly reduce airborne dust, mold spores, pollen, and even smoke. A 20x25x4 air filter captures at least 65 percent of particles between 1.0 and 3.0 microns in size. The thickness of the air filter ranges from 1 to 5 inches deep; some options are more common than others and the oven can determine the thickness you can use.