A louver assembly for placement in an opening for regulating the inlet of air, comprising a first blade stack and second blade stack arranged in tandem, and a sill for supporting the first and second blade stack. The first and second blade stacks have a plurality of blades arranged in a horizontally-spaced and vertically-extending configuration defining a plurality of horizontally-spaced and vertical extending air passageways for the passage of air therethrough. The sill has a generally planar first portion for supporting the first blade stack and a sloped second portion for supporting the second blade stack, wherein the sloped portion and the second blade stack define therebetween a void for equalizing pressure within the assembly to facilitate the draining of water therefrom.