• Window film is available in a variety of colours and densities to reduce glare
• Window film doesn't obstruct your view
• Window film doesn't feel dark from inside because it is transparent

A simple definition of glare is light in the wrong direction.

In an office environment most work surfaces are horizontal. This means that light coming from windows and traveling across the room is likely to cause glare. Glare forms a veil of luminance, reducing visibility or causing visual discomfort.

In many instances, the greatest benefit of a window is the ability to see out, rather than the illumination provided by the light coming in. Window film can reduce the light coming in, thereby reducing glare. It is also transparent so it does not obstruct your view like many internal shades do. Although a window can often provide useful light, particularly if the light is bouncing off the ceiling, glare can be a problem both at home and at work.

For windows, I find it most useful to classify glare into two categories; direct glare and indirect glare.

Indirect glare

Indirect glare is where the sun is illuminating an object in the field of view. This might be a building across the street or cars parked outside a shop front.

There are a large number of film products available to solve indirect glare problems.

The film can be from medium to dark depending on the severity of the problem. Very dark film is not usually required for indirect glare problems.

• Medium film has a light transmission around 35%
• Dark film has a light transmission around 20% to 15%
• Very dark film has a light transmission between 15% and 5%

Direct glare

Direct glare is where the sun is shining directly into your eyes or onto what you are trying to see. An example of the former is where a high window in a bedroom allows morning sun to shine directly into someone's eyes. An example of the latter is where the setting sun shines onto a checkout display so that it can't be read.

Direct glare often requires either a dark or very dark film in conjunction with some type of blind. This is because the sun's brightness is so intense that not even glass as black as welders' goggles can make it tolerable to look at directly. Therefore, at the worst times of day the blind may need to be closed.

The table below shows films for Glare Reduction. The heat figures are Total Solar Energy Rejected on 6mm clear glass.

Here are some photos from the inside looking out through various films.

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• Reflective film
• Overview - Selection
• Performance Table