Window blinds

Air conditioners moved to the category of familiar options, and this is good. But when the car stands for hours in the open summer sun, some parts of the body and, most importantly, the interior, can heat up to eighty degrees, or even more! The hand involuntarily pulls away from the red-hot surface, and the head begins to think: how to help the condition cope with the heat? The easiest solution is solar screens.
Varieties of such screens can not be counted - we easily acquired five products that cover the windshield. Everyone has a similar design: two reflective surfaces made on an aluminum base are separated by a foam core - a heat insulator. The approximate price is 150-200 rubles, the pedigree is eastern, the differences are in size, surface design and methods of attachment: suction cups, ties, etc. However, no instructions were found where, in fact, to fix the screen - outside or inside?
The question is not commonplace. In the vast majority of parked cars, the screens are hidden inside, and the reason for this is understandable. But from the point of view of physics, external placement is much preferable: reflected heat is better to dissipate in fresh air than to walk inside the cabin. Therefore, one part of the products has a cutout for the rear view mirror, while the other dispenses with it.
Such screens prevent the burnout of panels and upholstery. But manufacturers do not declare a specific decrease in temperature. We decided to fill the gap on our own, for which we used a pyrometer (non-contact temperature meter). Subjects became our Hyundai Getz and Solaris.
We waited for sunny weather when in the shade the thermometer showed + 25 ºС. By noon, the seatbacks, which were not exposed to the sun, warmed up to 48º, the dashboard to 70º, and the visors of the instrument cluster (they are almost perpendicular to the direction of the rays) - right up to 80º ! Well, we take two curtains, one shiny on two sides, the other with a pattern, and we put it on the windshields, and outside! Now it’s not a sin to dine - the thermal processes are inertial, so you need to wait an hour, or even another.
There is an effect! The sun warms even more, but in Solaris, covered with a curtain (shiny surface to the outside), the dash cooled to 46º, the visor to 47º, and the seat to 41º. This is no longer fatal and no longer looks like a sauna. Getz, which got the curtain with a picture, also cooled down, but a little less: 50, 51 and 43 ºС, respectively.
Journalistic fantasy immediately suggested a way to cool the interior more: you need to buy a couple more of the same curtains and put them … on the roof. It will be especially effective for black Getz. How to make the curtains stay there all day, another question. But our parking is guarded!
Is it worth it to cool the interior in this way? We think it's worth it. This is especially necessary for electronic devices that are stored in the glove compartment or, God forbid! - stand on the dashboard. We mean navigators, speakerphones, radar detectors, etc. In addition, it is much easier for the air conditioner (if it is, of course) to cope with the heat and bring the interior temperature to normal. And this, in turn, will save some fuel.