20x25x4 MERV 8, AC Furnace Air Filter, 3 PACK (CF100A1025-3PKAM) (Actual Dimensions: 19.94 x 24.87 x 4.38 in.)

Our new furnace requires an exact side even though it says one size. The three package is a good value and I change mine 3 times a year to get the best performance out of the furnace and a/c.

Besides the size, one of the most important things you need to pay attention to when it comes to air filters like this is the MERV rating. MERV stands for Minimum Efficiency Rating Value. This is an industry standard rating system that allows you to compare filters made by different manufacturers. A MERV rating is a numerical value ranging from 1 (lowest efficiency) to 20 (highest efficiency) and tells the consumer how well the filter captures and holds dirt and dust of a specified size range.This one is MERV 8. MERV 1-4 are typical of window unit air conditioners and capture only the largest partices. MERV 7-13 are very effective at removing most allergens. MERV 13 and above are hospital grade. The higher the MERV the more expensive it is to buy and operate because filters that capture smaller particles are denser which also reduces the amount of air flow through the filter and increases the workload on the furnace or device it is used in. In some cases using a filter with a MERV rating that is too high can damage the device it is used in. I use this MERV 8 filter in my home in Albuquerque where it gets very dusty, my vents are dust free and the AC/Furnace works efficiently so I guess it's doing its job well, I change it out annually and it is always fairly dirty on the intake side and relatively clean on the other side so I assume it's catching most of the dust/dirt/particles it encounters. I wouldn't mind spending a little more for a filter with a higher MERV rating if I felt this one wasn't cutting it but this filter is in fact doing a great job and I don't want to risk damaging or decreasing the life of my furnace/AC.

These are a must have for homes with big air vents. Installation was beyond easy. They’re sturdy and will last for months. I recommend writing the date on the top so you’ll know how long you’ve had it installed. There’s arrows that show which is the correct side to insert towards the vent. Based on the measurements it fit perfectly in the air vent. Highly recommend them.

There are lower-priced competitors, but scrimp on this. I have tried other brands and they performed poorly. When it comes to air filters, you need it to do its job well, and I will only trust Honeywell from now on. It fits perfectly. That's hugely important for protecting the life of my HVAC system.

Do the job btw they last a year didn’t know that.

they work as expected.

Our very pressure sensitive system works with these until they are coated up with dust. My system fan runs continuously and I change the filter every three months.

Honeywell media filters are made very well and work well too.