I recommend the merv 11 filters, before we used merv 8 and I would wake up in the morning with a throat full of phlegm and a scratchy voice. Really seems like the merv 11 traps more particals. I would buy them again.
I needed a really good filter for dust, dander and all the rest of the stuff I am allergic to, and my apartments heat pump has a really odd size filter. These guys come through every time!!