How much does window tinting cool down a room?

This one was a quick and dirty experiment.

A window film/tint was applied to a 100 sq ft room in my home that is south facing.

The specific product I used was the Gila Titanium Window Film product, which is applied on the interior side of the glass. The spec sheet says it blocks 72% of solar energy.

I did a quick data log of the temperatures the day before and after the tint was applied. The temperature datalogger (Kestrel 5200) was placed in the corner of the room away from direct sunlight. In order to get the most conservative values.

Result

During the hottest part of the day, it prevented the room from heating up by about 1 degree F.

General Thoughts

I'm happy that I did this. It makes the room more comfortable during the hottest part of the day, and there is a perceivable difference. Especially when standing in front of a tint vs non-tinted windows.

The only downside to this product is that it make the window a mirror at night. Meaning if someone is standing outside your window at night, and the room is lit. You will not see them.

It does not negatively affect the visibility when the sun is out, it is just slightly more dim.

Factors that affect the data

Keep in mind this is not a perfectly controlled experiment. Here are variables that could affect the final result.

• It was 2 different days, with variances with cloud cover and ambient temperatures
• Clear window data log was on Thursday, and tinted window datalog was on Saturday. Different room usage patterns.
• Room fan wasn't on. No air mixing to homogenize room air temperatures
• Temperature sensor was located in the corner of the room farthest from the window, and in shade. In order to get more conservative values.