Black car vs. white car

Most cars and clothes in the Middle East are white, in spite of having to be washed more often than black. In some countries the religion dictates black, but these are very much in the minority.

More specifically, it may not be so much a question of which is hotter or cooler, but how black or white allows heat equilibrium. Black color better allows the transmission of heat: heat flowing from a location of higher to lower temperature for equilibrium; while white conversely, is more resistive to the flow of heat, thus promoting a difference in temperature. That is why a black potbelly stove seems to radiate heat so well; but if one were to make that stove white, the stove may be hotter inside and the metal of the stove may be hot, while it would not seem to be as hot because less heat is radiating, or, flowing away from the source. If that stove continued to get hotter however, it may be expected that the function of heat being forced out would tend to turn that stove black: resistance breaks down. On a cold night, the same amount of heat would keep the inside of the white car warmer, while when It is hotter outside the white car will resist warming. Black both absorbs and radiates heat well, transmits that is, so whether the interior is black or white is also a factor in heat coming in from the outside. Maybe that is the social intimate feeling derived when people are dressed in black: body heat would be more sensed when two people in close proximity are wearing black.

I once owned a 1987 Mazda RX7 and quickly ditched it for the sole reason that it was black. Not only was it noticably hotter, but the finish was much harder to maintain. Dust, hard water stains, pollen, fuzz, hair, belly button lint all show up more on a black car. Also, scratches and swirl marks are much more pronounced in a black finish than most other colors. Sure, it looks uber cool, but from a practicality standpoint, it’s requires the most care.

True that. I noticed that in Iraq, Qatar and Kuwait there were a lot of black cars. More in Qatar and Kuwait. I asked our interpreter why, in some of the hottest parts of the world, someone would even consider a black car. His answer was that it’s a status symbol. If you have a white car, then you’re practical, thus poor (‘Poor’ meaning that you only have ONE kajillion bazilion dollars in the bank). If you have a black car, then you have a cool garage, a servant to polish it and to cool it off before you get in. Keep pumping that gas, world. You’re paying for modern day footmen.

Absolutely the dark car would heat up quicker. I was stationed in Hawaii many years ago and had a white International Scout. After living on the North Shore for a couple of years, the car developed a lot of rust spots. I had it sanded down and repainted a dark green. Boy what a mistake that was! On hot day, which were many, the poor air conditioner could not keep up like it could when the Scout was white. Therefore I had the advantage of scientifically proving the point. Because all other factors remaind equal except the color. Plus I had the advantage of experiencing two years of seasonal change in a white vehicle and almost two in a dark green one.
Sure loved that Scout. It was a sad day when International quit making them. They were prone to rust though.

Buy one of those window shades you put in the front windshield and call it a day

Black cars heat up more. Black interiors compound the problem.

The color we see is the combination of the frequencies in the visual spectrum that are reflected rather than absorbed. Black means all of the energy in the visual spectum is absorbed. White means that it’s all reflected.

Realize that all “color” is is a combination of those frequencies in the electromagnetic spectrum that excite the cells in the retinas in our eyes. That range of frequencies is called the “visual spectrum”. If no frequencies in the visual spectrum are reflected back at our retinas, none of the cells are excited and we see “black”. If all the colors are reflected back at us, all out retinal cells are excited and we see “white”.

The more radiant energy (light is electomagnetic energy) is absorbed, the more the item heats up.

Black = electromagnetic energy in the visual spectrum all absorbed = heat
White = electromagnetic energy in te visual spectrum all reflected = less heat (other frequencies outside the visual spectrum are absorned, so heat will happen).

Some frequencies of electromagnetic anergy pass right through, such as radio waves.

There is a reason for the white roofs on school buses after all! I also recall in the older NASA missions half the rocket was white and half black, to either absorb or reflect heat, whichever was needed. C):slight_smile:

@Harough:

Almost everything in your post reading “More specifically… wearing black” is wrong.

@DfromSD:

Are you sure you actually recall that? Sounds bogus to me.

Don’t know whether this was actually the case, but I remember reading somewhere that the now-defunct Braniff airlines found their fuel consumption increased significantly when they painted their planes various bright colors as part of their “Flying Colors” campaign. More fuel was needed to run cooling fans when the planes were on the ground.

Although Mythbusters did one experiment, as with most of their shows, they hardly come to scientific certainty. The Margin of Error on one trial is probably huge! Also, nine degrees does not seem much better to me if the car is 126 degrees! In order to be more certain there is a statistically significant difference between the two, they need to do many trials. They should also test it with different models. I would be far more interested to see whether this considerably affects fuel consumption, if the difference in temps is significant, during normal use.

Absolutely! I just listened to this episode on podcast, and that was exactly what I was thinking. First of all, I live in South Florida, and I can tell you from personal experience a black car IS hotter. Sure, once you are driving for a while, the a/c will cool just like any car, but imo, it takes longer to cool the cabin b/c it is hotter to begin with. That’s not scientific, just my own experience.

But my other thought was about the maintenance. ESPECIALLY if you have owned a white car for 20 years, which shows relatively little dirt, you will be very (unhappily, I believe) surprised how a black finish shows every fingerprint, speck of dust, surface scratch, swirl mark, etc (swirls and scratches are especially bad if you do not wash your car by hand and use car washes). While you can stretch washing a white car for a couple weeks, a black car looks filthy again in only a couple of days. It is also difficult to keep shiny, and in South Florida sun & heat, the paint seems to oxidize faster on a dark than a light car.

oh my, clearly you do not live in Florida ; )

Windshield shades help. I’ve seen people put them in the rear window AND windshield. They also make some for the side windows, but they are just a hassle.

Window tinting is a necessity in Florida due to the heat. It helps a LOT.

Cracking the windows is not an option, as spontaneous thundershowers are a daily occurance.

Yeah, I wondered about that 9 degrees. They normally film in the Bay area. Let’s say it was 70 degrees out. Black car went to 135 F, white one to 126 F. So the black car heated up 65 F, the white car 56 F, only about 15% less. Most of the heat comes through the windows, not the roof or doors. I never notice the headliner being hot in my black car, in Dallas, in the summer.

The most practical application I made from this was advising an oil company in a hot Latin American country. They pumped up heavy, thick oil and proudly stored it in the field in beautiful WHITE tanks. We convinced them to paint the tanks flat black and lo and behold, the oil was thinnerr and easier to pump, resulting in considerable power savings.

Happy client and a win-win situation.

Pretty much a perfect solution - passive, nothing can break, and it doesn’t create operating costs - ?Excelente!

http://www.jcwhitney.com/side-window-deflectors-and-visors/c1570j1s17.jcwx
Go ahead and crack those windows.

Ingenious! And an excellent example proving the point that black asorbs more of the sun’s energy than white does.

It also illustrates the principle that much of the absorbed energy is then transferred through the base material to its contents. In your case, the oil. In the OP’s case, the cabin air.

He’s correct – see the rings of black and white paint squares at http://hubpages.com/hub/NASA-Project-Mercury-Launch-Vehicles. We used to measure the relative size of the squares to prove the contractor had done it correctly.