Should the coated side of coated glass face outward or inward?

The orientation of the coated surface on coated glass should be determined based on glass type, climate conditions, and usage requirements. Below are common scenarios:

Single-Pane Coated Glass:

Generally, the coated surface of single-pane coated glass should face indoors. This is because the coating layer is typically fragile. Facing inward protects it from direct exposure to external elements (such as rain, wind, sand, and UV rays), thereby extending the coating's lifespan.
Insulated Coated Glass:

Low-E Glass (Low-Emission Glass):
Northern Cold Regions: The coated surface is usually oriented toward the third surface of the insulated glass unit (i.e., the side closest to the interior). This reflects indoor heating radiation (far-infrared rays) back into the room, reducing heat loss and improving thermal insulation.
Hot Southern Regions: The coated surface generally faces the second pane of the insulated unit (the one closer to the outdoors). This effectively reflects outdoor solar heat radiation, reducing heat transfer into the room and providing heat insulation and sunshade.
Heat-reflective coated glass: Primarily used for heat insulation and sunshading, the coated surface usually faces outward. By reflecting infrared rays from sunlight, it reduces heat entering the interior, suitable for hot summer regions or orientations with strong direct sunlight.
In summary, the orientation of the coated surface on coated glass should be determined by comprehensively considering local climate, building functionality, and usage requirements. It is recommended to consult professionals or refer to product manuals before installation.