You mentioned “…it will help delay the amount of time it takes for a parked car’s interior to heat up…”

I can accept your explanation if the duration the car is parked under the sun is short. Sometimes we park our car for just a few minutes to run an errand. I suppose in such a situation where the duration is too short to achieve thermal “equilibrium”, the interior air temperature of the car would be cooler compared to one without the film installed.

It has been a pleasure having this technical discussion with you. It did help to further convinced me that the few thousand dollars spent installing solar film in all my cars was definitely worth it. Nevertheless, I will still keep searching in the Internet for the elusive test data of the car parked under the sun for an extended duration. (my car is usually parked at my work place from morning till later afternoon under the blazing tropical sun)

So let’s say we were to set out to conduct an outdoor experiment. Could we duplicate all conditions? We would need 3 like model cars and we would have to test them all at the exact same time in the exact same orientation and in the exact same position to make all things “equal.” The first three criteria are doable but the last is impossible. So an outdoor experiment would be slightly skewed. Someone could take issue with that and probably would…

I understand your position but I really doubt it is marketing ploy as you suspect.

Just a minor clarification, when I mentioned cooler ambient temperature, I meant relative to a parked car without solar film.

Secondly, you went to some length trying to explain the benefit of the solar film while driving. Allow me to admit…I am a total believer of this already as my 3 previous cars and present one all had solar film installed but I am just very skeptical about the benefit of the solar film (again I stress any type of solar film) in moderating the air temperature of a car parked under the hot sun for a long duration unless an actual real world test shows otherwise. I have yet to locate any such test results on the Internet hence I can only conclude that such a real world parked car test if exist is deemed not a positive promotion of their products hence not published. By the way I live in the tropics.

Some disclosure is in order here. We did not conduct this test. Vision Quest Distributing is simply publishing the results on our blog of a test that was done by an independent lab. Personally, if it were me I would have suspended the data loggers in the air using something that is non-conductive. Setting them on the dash is kind of shooting themselves in the foot because you do get thermal bridging from the dash absorbing energy.

Even if you were to measure ambient temperature this way, what you will find is a warming trend at varying levels depending on the film’s ability to filter energy. It would be very similar to the graph we have just maybe the exact temps would differ slightly from the temps shown here but the spread from one test vehicle to the next would be very similar. A decrease in ambient temperature is really not possible. The reason being is that window film does not cool vehicles. Air conditioners are what cool or condition the air, the film just filters incoming energy from the sun that transmits through the glass and the glass only. Reduced solar transmission decreases the rate of heat gain and lowers the cooling demand thus the air conditioner will not have to work as hard to reach the desired set point.

There is another factor that is not taken into consideration in this experiment and that is reduced energy absorption. Incoming near infrared is absorbed by interiors and us and then is re-radiated as heat. Window films have the capability of filtering out near infrared so while we are driving we feel more comfortable behind a filmed window because the IR transmittance and resulting absorbance is greatly reduced. There is no substitute for real world park it out in the sun results, but in this case the lab becomes the equalizer between the control and test subjects and gives some numbers for those that ask. At the end of the day if you were to drive in a vehicle filmed with Huper Optik versus an unfilmed vehicle or even a vehicle with traditional window film, you would definitely be able to tell the difference.

You mentioned that you are measuring the ambient temperature but I could not quite agree on this. To measure ambient temperature, the probe should not see the heat lamps directly and away from a heat absorption surface such as the dash board.

In a real world, a car parked under the hot sun gets a lot of conducted heat into the interior from the metal roof/surfaces/windows in addition to radiant heat from the windows. Therefore, I wonder if a solar film (any type) actually helps in reducing the ambient air temperature in a stationary car much. Nevertheless I am a full believer of the benefit of solar film for a car on the move during a sunny day.

I was hoping someone could conduct a simple experiment and put to rest the “burning” question whether solar film can make the ambient temperature of a stationary car under the sun cooler. I suppose the experiment would just need two identical cars. One with window film and another without. A protruding temperature sensors in the middle of the car, sheltered from direct sun light would then measure the interior AIR temperature after achieving equilibrium, say after 2 hours.

The important thing to take note is the temperate spread as time goes on. Referring back to the article notice that; “The entire logging time for each cycle is 120 minutes. This is to allow sufficient time for the car to attain thermal equilibrium, ie the maximum temperature attained in order to stress the films to the maximum extent of filtering out the solar heat.”

Thank you for your comment.