Accumulair Diamond 14x30x1 (13.5x29.5) MERV 13 Air Filter/Furnace Filters (2 Pack) Nominal Size 14x30x1. Actual Size 13.5 x 29.5 x 0.75 MERV 13 Rating. Great for helping reduce airborne allergens such as bacteria, particles that carry viruses, pollen, mold spores, fine dust, and pet dander. Each filter lasts up to 3 months. Electrostatically charged filter media captures airborne allergens smaller than 1 micron! 2 Pack of Air Filters