Try the room from outside
A sheer curtain may feel private while you stand inside looking towards a bright street. That is not enough to establish what somebody outside can see. Its weave, colour, fullness and the difference in light between indoors and outdoors all affect the view.
Test the actual fabric if privacy matters. In a safe and accessible position outside your own home, ask another household member to look into the room while its usual lights are on. Do not rely on the daytime impression or a product photograph. If an outside check is not possible, ask the supplier about the intended privacy performance and consider a more opaque covering.
Check from the relevant angle. A ground-floor window facing the pavement has different sightlines from a high window overlooking a garden.
Give the sheer a defined job
A sheer can filter the appearance of daylight, soften a view and make a large window feel less bare. Those are useful roles even when another curtain handles evening privacy. Decide which task belongs to each layer rather than expecting one light fabric to do everything.
If adding a heavier curtain, make sure both layers can move without catching each other. The poles or tracks need enough space and must suit the weight of the coverings. Check the closed arrangement as well as the neatly drawn-back version shown in a shop.
Avoid assuming that extra fullness automatically produces reliable privacy. More folds change the view, but the actual fabric and lighting still need testing.
Keep the window usable
The combined coverings should leave access to handles and ventilation arrangements. Keep fabric clear of heaters according to their instructions, and ensure hems do not create a trip point beside doors or furniture.
Where a system uses cords or chains, use its safety devices and follow the manufacturer's installation guidance. A soft-looking window treatment can still contain hazardous operating parts.
Make the evening check part of the purchase decision, not a surprise after hanging. If the sheer is chosen for its texture and daylight appearance, pairing it with an appropriate opaque layer allows it to perform that role without making an unsupported promise about privacy.
