I have a newly installed Lennox HVAC system that uses one of those
several inch-thick -- HCF 20-16, to be precise. The filter that was
installed with it was a MERV 16. I see that these filters, which need
to be replaced roughly once every 6-12 months, cost about $100, while
the MERV 13 versions cost about a third of that.
So, OK, what's the value of MERV 16, compared to MERV 13? Allergens
are not an issue, and since the new system was installed with the
thick filters, replacing an old one with the thin filters, I really
don't see any less dust accumulation in the house. I would assume the
ducts are being kept similarly dust free. The ducts have actually
never needed cleaning.
So why should I pay $60 more for a MERV 16 filter? Yes, I understand
you get what you pay for, but I don't see me getting $60 of value.