I remember this test from a German automobile club:
Temperaturen von 60 Grad im Auto sind im Sommer keine Seltenheit. Doch was kann man dagegen tun? Sonnenschutz-Zubehör im ADAC Check.
www.adac.de
Here is the translation from deepl.com. You might have a look on the grafics in the link. One very intersting pint you find in the last sentence!
The interior of parked cars can heat up very quickly in sunny locations. Temperatures of 60 degrees in the vehicle are then not uncommon. But what really helps against the heating? The ADAC technology experts have found out.
-Sun protection films and "half garages" reduce temperature well
-Cars with light-colored paintwork heat up less strongly
-Surfaces in the vehicle can become red-hot without protection
In any case, sun protection accessories for cars promise relief from hot, summer temperatures and help reduce the amount of heat generated inside the vehicle. In a study, engineers at the ADAC Technical Center in Landsberg am Lech, Germany, tested what helps best against heat buildup. To do this, seven vehicles were equipped with appropriate sunshade accessories, parked in the sun and the temperature development in the midday heat was recorded.
Why sun protection for cars helps in the heat
The ADAC check included: a tarpaulin for the windows all around (a so-called half-garage), a reflective sun protection film for the outside, a white fabric cloth to place on the dashboard and a reflective sun protection screen for the interior. In addition, a vehicle with tinted side and rear windows was examined. But which sun protection accessory brings the most?
As the graph shows, the reference vehicle heated up to 53 degrees in midsummer weather without any other measures. The tarpaulin (half-garage) showed the best effect. With its help, it only got to 43 degrees inside the test car. The sun protection film applied on the outside provided a satisfactory solution (45 degrees). Applied inside, the sunshade (49 degrees) and the white cloth on the dashboard (50 degrees) had the least effect.
"Half-garage" protects best
The best sun protection for a car parked in the sun is offered by the tarpaulin or so-called half-garage, as the vehicle interior is protected all around from the sun's rays and thus cannot heat up as much. In the ADAC measurements, the temperature in the vehicle under a half-garage was a considerable 10 degrees lower than in the car without sun protection measures.
Sun protection film on the outside makes sense
By applying a sun protection film on the outside of the windshield, the sun's rays are reflected. This effectively prevents the seat covers and also the dashboards from heating up. After all, the air temperature inside the vehicle is eight degrees lower than without sunscreen. It is therefore the second-best protection against heat in the car.
Interior sunshade: Better than nothing
A sun visor that can be fitted inside the car also reduces the amount of heat generated in the car. However, only by four degrees compared to the reference vehicle without a sun visor. Moreover, the sun visor only offers an effect against heat if it corresponds exactly to the size of the interior window. This is often not the case and the effect is therefore even smaller.
Tinting film: Surfaces stay cooler
The situation is similar with window tinting - an optional extra for the window surfaces from the B-pillar onward. Tinted windows reduce heating in the interior by only two degrees, but the surface temperatures on the rear seat bench show a clear effect. Without window tinting the temperature is 57 degrees, with tinting it is only 48 degrees. This is a noticeable difference, especially for children and infants - even during a longer trip.
Why light-colored cars heat up less
In a test scenario, ADAC engineers also specifically checked the paint temperature of a white and a black car. The result: The color of the car's paint makes a small but definitely noticeable difference to the temperature inside the vehicle. The surface of the black car heated up to a paint temperature of 65 degrees in the midday heat with the sun high in the sky, while that of the white car was only 44 degrees.
Although the external paint temperature is transferred much less to the vehicle interior, the temperature difference is noticeable to the body. Specifically, the temperature inside the white car was five degrees cooler than in the black car.
What is the reason for this? The more radiation an object can absorb, the more energy it can absorb. This energy can then be converted into other forms of energy, such as heat. A black car therefore absorbs much more radiation and thus stores much more energy than a white car. So, all things being equal, a black car will be warmer than a white car. The measured interior temperature of 53 degrees for the black car represents a tangible difference from the measured 48 degrees for the white car.
By the way: Heated dark surfaces in the interior in particular contribute significantly to the heating - more than the vehicle paintwork itself.
Translated with
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