@rains_hope @CorsIAQ The Filtrete brand 1" MERV 13 have very high pleat count (media surface area) and low pressure drop. They work well. For other brands, caveat emptor.
@rains_hope @CorsIAQ Filtrete 品牌 1" MERV 13 具有非常高的褶皱数（介质表面积）和低压降。它们运作良好。对于其他品牌，请自告奋勇。