What is the difference between a vertical and horizontal night cover?

A vertical night cover (or night blind or night curtain) is a cover that is installed on an open refrigerated display case to create a thermal barrier, trapping cold air inside the display case, to keep products cool (think the dairy case in your grocery store). It is often installed on the canopy of the case and is pulled down vertically (similar to pulling down a window shade) to cover the case opening.

A horizontal night cover serves the same purpose. The difference is that it is deployed horizontally on horizontal cases (like the open tubs or freezer cases in the middle aisles of the frozen section).

These covers keep products cool while reflecting ambient store heat and light away from the case. They save energy and reduce product loss for grocery retailers. The most effective material for a night cover is perforated woven aluminum as it has the highest reflectivity and lowest emissivity values.