Private or Public? Discussing the science behind one-way mirror window film.

Today we will be discussing one of the most common question asked by my customers – is there a window film that allows me to look out clearly, but at the same time cannot be viewed in from outside? In other words, do you have a one-way mirror window film?

Before I give my answer to the question above, i have to stress that there is no complete solution to achieve one-way vision privacy regardless in the day or night.

All films function under this same and simple theory – whichever area is brighter, the person viewing in will not be able to see. Thus achieving this total privacy during the day is possible as it will be brighter outside than inside the house. The owner can enjoy the clear view from inside, while everyone will not be able to look in.

Switching this to night time, where the inside of the house is brighter than the outside, the opposite happens. The owner will not be able to view outside (only seeing his/her own reflection) while everyone outside will be able to look in clearly.

Shining a powerful light onto the outside surface of the window is a way to maintain privacy at night, but of course this is not feasible. Therefore before plunging in to choose the darkest and most reflective window film available and thinking no one can see into your house, think again. This is only applicable in the day, and not in the night. Moreover, there are rules in Singapore where buildings are not allowed to install films with light reflectivity over 20%.

Quoting from BCA: The use of building materials with daylight reflectance exceeding 20% on all external surfaces is currently prohibited under the Sixth Schedule (“Prohibited Construction Materials”) of the BC Regulations.

To achieve total privacy and heat rejection, i would suggest installing both window film and curtains/blinds. Curtains/blinds are there to give you the privacy you need at night, while our window film can help to reject those nasty heat in the day.

Still confused and want to find out more?

Contact us anytime and we are happy to explain.