Advantages to Tinted Windows and Sunscreens
Both tinted windows and sunscreens can reduce heat from the sun by reducing the light (and thus heat) that enters through the glass as well as the heat absorbed by the glass and transmitted into the house. This last effect is measured as "solar heat gain co-efficient."
Advantages and Disadvantages of Tinted Windows
Tinted windows only limit sunlight when the window is shut. With this method, you can enjoy either shade or air circulation, but not both. This limitation may not be an issue for some windows, such as a decorative foyer window that doesn't open. The tinted pane itself can absorb solar heat and transmit it into the home. This process is especially important when tinting existing windows with a film. Solar heat that isn't reflected or transmitted can be trapped between the pane and an improperly applied film, creating temperatures that stress the pane and affect the windows' warranty.
Advantages and Disadvantages of Sunscreens
Sunscreens can reduce visibility from the outside more than tint. Unlike tinting, sunscreens allow solar heat to circulate away before being absorbed by the panes and transmitted into the home. According to the Efficient Windows Collaborative, this circulation can reduce a window's solar heat gain co-efficient by 30 to 70 percent. Sunscreens also give homeowners the flexibility of opening windows to increase air circulation and removing the panes in winter to allow more solar heat, which reduces heating bills.