12x12x1 (11.7 x 11.7) Filtrete Ultimate Allergen Reduction 1900 Filter by 3M

I started using 1500 moved up to 1900 and I love both of them and recommend them to anyone who has allergies or a family member who does. Before my son could not rest well and sneezed constantly. I thought if I dusted and vacuumed everyday it would be ok. It wasn't until I started using Filtrete 1500 -1900 that he was able to stopped being so missable. It DOES make the difference. [This review was collected as part of a promotion.]

I've been using Filtrete air filters in my A/C since my house was built. First I started with the red filters (1000), but upgraded to the purple (1500) ones and now the blue (1900) version. The 1500 and 1900 versions have much more filter surface area to catch particles than the 1000 version so I use only those now. But frankly, I can't say whether the blue 1900 version is any better than the purple 1500 filter. I think it's more important to make sure you don't let your filters go too long between changes. My neighbor only changes his when they start looking like a fur coat. That's way too long and will overtax your HVAC. He's already had to replace his central A/C after only twelve years. Tip: write the date you installed the new filter all along its frame. That way you can see the date just by looking up at the air return without having to get a ladder and opening it up. [This review was collected as part of a promotion.]