Dark vs light cars: which get hotter in sun?

[amitxjoshi]

Here's a question which has been puzzling me as I debate buying a new car: is it true that dark colored cars get hotter in the sun than do light colored cars?

[R. P. McMurphy]

Yes.

[A.R. Cane]

I don't think the difference is that dramatic, total glass area, window tinting, would probably have more effect than body color. Personally, I wouldn't choose a car's color just for that reason.

[don't ask]

When I bought my car the woman who is the quality control manager at the dealer made an interesting comment. She said I was smart getting the silver/grey paintwork because it keeps clean better. When i asked what she meant she explained that light colours and dark colours both look really dirty with any dirt on them at all however grey cars don't show it as much. I hadn't known but you only have to look closely at a few cars to see that she is right.

[SkeptiJess]

My husband has a dark gray Passat and it gets much hotter inside than my cream-colored PT Cruiser. However, my Cruiser has tinted windows and the Passat doesn't -- that may account for more of the difference than the color does.

[Princhester]

A friend of mine in High School did this as a science project. His father collected a particular sort of car (I can't remember what it was, now) and consequently had about six of them in various colours. He lined them up in a field (they lived on a semi rural property) all facing the same way and took measurements. Don't ask me to remember numbers (I'm talking more than 20 years ago) but I do remember that the difference in internal temp between black and white was huge.

[GuanoLad]

They investigated this in Mythbusters, and the results were that dark cars do get hotter - slowly to start with, but eventually to a very high temperature, compared to light coloured cars.

[CC]

Princhester, I think we'll assume that the darker cars were the ones with the higher temperatures, but in the interest of science, can you at least provide some data?

[FormerMarineGuy]

Exactly what you are looking for: Car Color Surface Temperature Data (http://enerjazz.com/data/cartempsurf/)

If you look at the chart, it says the roof of the cars is where the temperatures are taken. So now it probably depends on the insulation and thickness of the roof, and how much of that heat gets in, although it probably does not have a huge effect.

I work at a dealership in South Florida so it seems to me that all cars are hot. FROM EXPERIENCE, I think that the interior color of the car makes a bigger difference than the exterior. Although all of our cars are leather, cloth is also a little cooler, as it does not hold in the heat.

[kanicbird]

Just a side issue, if you are trying to decide on a color for a new car. I have noticed that some colors are, for some reason, harder to see. I had one light tan car that this was very evident with, to the point that I eventually drove with the headlights on all the time, which helped out.

[Rigamarole]

Anecdotal evidence: I have a light blue colored car, and it still gets frigging Oh-I-see-I-just-stepped-into-an-oven hot.

[Blaster Master]

Sorry, can't find a cite at the moment, but Mythbusters did test this on one of their shows. They had two identical cars except in exterior color. If I remember correctly, it was at least 20 degrees hotter in the black car than the white car.

[Mangetout]

Any car will be destroyed long before it reaches the sun, so, in practical terms, any colour of car you put in the sun will reach approximately the same temperature as any other colour.

Hope this helps.

[Cervaise]

Any car will be destroyed long before it reaches the sunSurely not this one (http://en.wikipedia.org/wiki/Pontiac_Sunfire).

[chowder]

Princhester, I think we'll assume that the darker cars were the ones with the higher temperatures, but in the interest of science, can you at least provide some data?
Not so much data but you have to remember that light colours will reflect more of the suns rays than will dark ones which will absorb them....

[CC]

Um, Chowder, excusing me for asking you to not to be speaking for Princhester, but please to not to be involving yourself in this particular conversation unless you are, on behalf of Princhester, speaking on his behalf, inasmuch as it was himself who I had asked for information, not yourself, as I am, and have been aware of the basics of the science attendant upon this particular question. Thanking you in advance, xo, C.

[Gary T]

Um, Chowder, excusing me for asking you to not to be speaking for Princhester, but please to not to be involving yourself in this particular conversation unless you are, on behalf of Princhester, speaking on his behalf, inasmuch as it was himself who I had asked for information, not yourself, as I am, and have been aware of the basics of the science attendant upon this particular question. Thanking you in advance, xo, C.
And please be noticing that Princhester is having already said "Don't ask me to remember numbers (I'm talking more than 20 years ago)," inasmuch as he ain't got no data. :D

[CC]

I'm noticing. And I'm still thinking that "huge" may mean 15 degrees, 40 degrees, 65 degrees or more. Maybe Princhester can remember that much without the specificity of the numbers. Maybe too much to ask, maybe not. But I'd be willing to see if he remembers a range. It's an interesting experiment. Ya mind?

[Speaker for the Dead]

I'm noticing. And I'm still thinking that "huge" may mean 15 degrees, 40 degrees, 65 degrees or more. Maybe Princhester can remember that much without the specificity of the numbers. Maybe too much to ask, maybe not. But I'd be willing to see if he remembers a range. It's an interesting experiment. Ya mind?
I'm not quite sure if this is what you're looking for, but I think someone had a bit of data earlier (http://boards.straightdope.com/sdmb/showpost.php?p=7657319&postcount=9). I don't mean to speak on FormerMarineGuy's behalf, but I'm trying to save him the effort of repeating himself.

[kanicbird]

Could you generate power from the tempeture difference between a black and white car?

[Princhester]

Sheesh, sorry, way to leave out a vital point, Princhester :)

Ahem. The dark cars were hotter.

As to a range. Hmmm. I'm surmising as much as remembering, here, but I do recall thinking the difference was huge, and I suspect that means 2 digits or at least close to that. So maybe about 10 degrees celsius might be about right. Take this with a great degree of skepticism though.

[amitxjoshi]

Hey GuanoLad and MasterBlaster: thanks for the tip, I searched Wikipedia for the Mythbuster's experiment, and found this from their third season:

"A fan wrote in and asked a follow up question: "Does the color of a car affect the way it heats up?". The MythBusters used two identical cars, one black the other white and left them both out in the summer heat with thermometers in both. By mid-afternoon the black car had heated up to a temperature of 135°F while the white car topped off at 126°F, almost 10° cooler."

Excellent! This is much less extreme than the graphs at http://enerjazz.com/data/cartempsurf/ would suggest, probably because they were measuring temperature a little differently (just under the roof, as against some sort of average measure in the interior, I would guess).

[enipla]

Another thing to consider is what color you pick for the inside of the car. And the strength of the sun. I don’t live in a hot area, but I do live at altitude and I do get down to Denver enough that made me chose a tan interior over black.

[scr4]

Could you generate power from the tempeture difference between a black and white car?
In theory, yes. White paint is actually a decent radiator, even when it's sitting in direct sunlight. It absorbs very little visible light, but emits infrared just fine. Just put a thermocouple between a black metal plate and a white plate, and you get electricity.

But it would be even more efficient if you put the radiator in the shade. And even then it won't be as efficient as a photovoltaic cell (regular solar panel).

[Balthisar]

Some anecdotal evidence -- last year I lived in Sonora, Mexico -- the Sonoran Desert. It gets to 120 in the summer. It sucks. My company car was a black car with a black interior. Who the hell in their right mind bought this thing? None of the locals ran around in black cars. If I didn't park in the shade or throw a towel over the steering wheel, I couldn't grip the thing. The residual radiant heat from the interior was such that the air conditioner wouldn't do a thing to make the cabin comfortable in the 25 minutes between work and my house. It sucked, and it sucked big. At the same time, I had a personal vehicle there -- different make, but I'd bought it in Arizona, which is also in the Sonoran Desert. Grey exterior, grey interior, and perfectly tolerable after being parked in the sun all day.

On on the road again, and now my loaned car is black with a tan interior (happens to be the same car that I was in Sonora for in the first place). Ontario had a major heat wave last week, and despite being black on the outside, it was just as comfortable as my own personal car with a tan interior and a maroon exterior. (All the same, the company loaner has air conditioned seats! Man, I've got to think about replacing my aging personal car!)

[Contrapuntal]

What is it about cars that make them special? Don't most dark things absorb more heat than most white things? Especially when other factors are the same?

[scr4]

What is it about cars that make them special? Don't most dark things absorb more heat than most white things? Especially when other factors are the same?
In general, yes. But there are exceptions. For example, black clothing can keep you cooler than white clothing (http://www.straightdope.com/mailbag/mblackcool.html) under certain conditions. Since a car is a fairly complex system, it's perfectly reasonable to ask if a black car is really hotter, and if so, whether the difference is significant or not.