How much does the color of a car's interior contribute to its surface
temperature?  I care about the worst case scenario (several hours of
direct sunlight exposure on a 100 degree day).  How much temperature
difference is there between a black leather interior, versus a lighter
color like tan or grey?

---

Request for Question Clarification by crabcakes-ga on 11 Nov 2002 22:29 PST

Hello pk2200,

I was able to find information about car interior colors, but none on
leather interiors.
I have found some studies on colored interiors, as well as the effects
of the exterior colors. The studies used ambient temperatures of
80-100 degrees. Would this suffice? If so, I’ll post the answer.
Regards,
crabcakes

---

Clarification of Question by pk2200-ga on 11 Nov 2002 23:34 PST

Yes, that would suffice.  I care less about the leather and more about
the color comparison.  Thanks for the quick response.

Hello again pk2200,

One of the reasons your question interested me is that I live in
Arizona, where almost ANYTHING left in a car in the summer, will melt
in minutes-Dry heat or not!  Out here, they say, once it reaches 110
degrees, it is just plain unbearable...a rise in temperature of a few
more degrees is not detectable--we are already baked!!!

A few hot summers  ago, a local television station ran an uncontrolled
experiment at a car dealer on this very topic. I can find no data or
reference to the "study", but they determined that lighter interiors
were cooler after an hour, by up to 10 degrees than the dark
interiors.

I did find reference to Click and Clack "Car Talk" program's
discussion of this topic, but that was all it was, a reference. There
was no hard data to be found on their site.

What I DID find: 

According to the National Safe Kids Organization, if the ambient
temperature is 79 degrees F, car interiors can reach the following
temperatures!

 White Interior             135 degrees F
 Red   Interior             154 degrees F
 Blue/Green Interior        165 degrees F
 Black Interior             192 degrees F
http://www.kidsource.com/kidsource/content3/news3/temperatures.safety.all.html


In this 1995 study,  interior temperatures on vehicles of  dark blue
or light grey EXTERIORS were studied. The outside ambient temperature
was 93°F, and it was partly cloudy.  Within 20 minutes, the interior
temperature in both cars exceeded 125°F.
http://www.injuryprevention.org/states/la/hotcars/hotcars.htm


In this study, the cars studied had stabilized temperatures of 120
degrees in two hours. The lighter cars took a bit longer to reach the
120 degree mark, but by the end of the two hours, the temperatures in
all vehicles  were almost identical, and stable.( This is also
mentioned in unstable-ga’s  comment below)
http://ggweather.com/heat/


According to this CDC report, “cars parked in direct sunlight can
reach internal temperatures up to 131 F-172 F (55 C-78 C) when outside
temperatures are 80 F-100 F (27 C-38 C) (6,7).”
“In at least two incidents during the summer of 1998, deaths occurred
in dark cars, and the dark color”
http://www.cdc.gov/mmwr/preview/mmwrhtml/00055794.htm 


The Dangers of Interior Heat
http://www.canadiandriver.com/articles/jk/020522.htm

General heat absorption and cars. (This site has some broken links,
but the page has some interesting reading!)
http://www.madsci.org/posts/archives/oct98/904941057.Ph.r.html

Effects of heat on cars:
http://www.shedrives.com/scholar.asp?Loc=RS&scholar=0800

Hope this helps!

Regards,
crabcakes

Search Stategy:
car interior + heat
auto interior + temperature

This isn't hard data but I recall the Car Talk guys commenting on
exterior car colors and temperature and saying that they had studied
the matter (or read a study on it) and discovered that the exterior
color of a car made very little difference.

I suspect the same is true of the interior -- I doubt that you're
dealing with a large enough surface area for the color to make much
actual difference. It's entirely possible that there is a perception
of difference by a human occupant, however.

-Coach-

To add to coachschorr's comment, I note that u stated several hours of
exposure.
At such long time exposure, the colors is also not likely to
contribute to too much difference as heat trapped in the car would
accumulate up to a max and stabilize, i.e. it would not continually go
up and up, so if the time is long enough, the color would not make any
difference as all the cars would reach the same max (which is dictated
by a lot of other stuff i.e. amount of air volume inside your car, the
pressure on the particular day, the type of metal and interior
finishing material etc.)

What we do know is that black colored materials tend to gain and loose
heat fastest compared to other lighter colored materials (provided its
the same kind of material)