Heat protection has suction cups for window darkening. The window sunshade protects living rooms, bedrooms and offices from direct sunlight in summer and thus serves as an ideal glare shield. At the same time, excessive heating of the room is prevented by the darkening effect. Thanks to several suction cups, the universal blackout can be flexibly attached to skylights as well as in cars, trains or mobile homes. Dirty blackout blinds can be cleaned at 30 degrees in the washing machine.