Reflective window film (one-way mirror)
Reflective window film, also called one-way mirror film or one-way reflective film, carries a metallised or ceramic layer that bounces light back off the brighter side of the glass. During daylight hours the outside is brighter, so the window reads as a mirror from the street while you look out normally from inside. Because it is working on light rather than opacity, it is the only privacy option that preserves your view, which is why it belongs on living rooms, home offices and any window with an outlook worth keeping.
Reflective films also reject a serious amount of solar heat, so a west-facing lounge that gets privacy also gets a cooler afternoon. The trade-off is the night-time reversal: once your interior lights are the brighter source, the mirror flips and you become visible. Plan for a sheer or blind on rooms you use after dark, or step up to frosted film if 24-hour privacy matters more than the view.
Related: residential window tinting, 3M window tinting and All-Season window insulation film if winter warmth is your main goal. Also read Window Film vs Curtains and Blinds: Which Is Better? to compare film with curtains, blinds and shutters for privacy, glare and blackout.

