How efficient are Sun Screens vs. Window Film?

OUR WINDOW TREATMENT EXPERIMENT

Both bedrooms are similar in size, west facing, with the same window arrangements. On window #1 we installed an exterior sun screen, on window #2 we installed interior window film.

We turned off fans and lights in both bedrooms and placed a drinking glass in the light shining on the floor to measure both the temperature of the windows themselves and objects in the room. We measured the same panel of glass in each experiment and we measured identical panels in each room.

TIME	PLACE	ITEM	TEMPERATURE
2:40pm	Bedroom #1	Window Temperature Glass Temperature	93 83
	Bedroom #2	Window Temperature Glass Temperature	102 83
4:00pm	Bedroom #1	Window Temperature Glass Temperature	98 85
	Bedroom #2	Window Temperature Glass Temperature	113 85
4:50pm	Bedroom #1	Window Temperature Glass Temperature	99 85
	Bedroom #2	Window Temperature Glass Temperature	108 84

Conclusion: Window in bedroom #2 was substantially hotter to the touch but both treatments work well and offer relief from the sun. The way the light looks and feels with the window film is a softer, more diffused light, however the privacy of the screens and the fact that they cut more heat from entering the home may be a more attractive option for your investment.