Living in Sunny So Cal, we are concerned about color choices because of the heat they generate. At first our choice was the Pepper White, but just as we were about to order the new color, Moonwalk Grey appeared. We like the color, but be aware.....
Moonwalk Grey is as hot as the Black.
I measured surface temp today at the dealer.
The reds, charcoals and dark colors are hot. but the grey is deceptively HOT.
NOTE. the White Silver is very cOOl .
The cOOlest is the bright white on the Countryman.
Fried eggs anyone?

 

How did you measure the surface temperature? IR thermometer? Can you post up some numbers? I have a hard time believing there is that much difference in actual temperature between the colors.

 

In Doubt?
In direct sun:
Put your hand flat on the hood of various colors and experience the phenomenon.
You can manage this simple experiment in any parking lot.
The Mini dealers lot sampling will be definitive however.

 

IR HandPalm
It's the latest trend
You can get the adapter off eBay
If I remember correctly, it's a China thing! 😎

 

Why? Color is created by reflecting some wavelengths and absorbing all the rest. Black absorbs almost everything. Dark colors absorb most light, which is why we call them "dark".

Sunlight imparts about 15 watts per square foot of energy to any surface (average). My clubman is 155" by 66", or 71 square feet. Of course the corners are rounded, so let's take off ~10% and call it 63 ft^2. So, 945 watts of energy are hitting that car all the time.

If watts aren't your speed, BTUs (the units by which space heaters and air conditioners are rated) may be useful. The sun imparts 433 BTU/hr per square foot. So, the sun is a 27,279 BTU heater on my Clubman.

Now, when it comes to paint, nothing is perfect. The blackest black reflects about 5% of light (that's why you can see a black thing's shape and contours), while white paints max out around 85% reflection. (Oddly, some yellow paints can get into the 90's.)

Some cars are going to reflect lots of light, others far less. Which is going to build up more heat?

Basic physics. Not to mention anyone who has lived in the south knows the difference a white car vs a black one makes. :-)


If numbers aren't convincing, perhaps an appeal to authority? http://www.straightdope.com/columns/...oler-in-summer is relevant.

Or better yet, here is a guy who actually did measurements: http://tom-morrow-land.com/tests/cartemp/index.htm
He found that the average difference of surface temperature between black and white Toyotas was about 56°F. I know which I'd rather lean against on a hot, sunny day!

 

WOW! Fantastic post, thank you.

The reason I asked is because this topic comes up all the time on the motorcycle forum (black vs. white helmet). I've never seen any empirical data like you posted, so I'll pass the link(s) along.

What's interesting is that his test showed that the interior of the black car was only marginally hotter than the white car, even though the outside paint temperature was considerably higher.

 

In most of Canada our cars come with block heaters.

They used to have interior car warmers and remote car starters that would come on when the temperature was below some level.

The dealer refused to install an interior car warmer in my 2006 MINI, and you couldn't add a car starter without a modification to bury a key in the firewall.

Why did plug-in car coolers never happen?

 

There are plug in(12v) coolers, they suck "lotsa" Amps!

 

Actually I was hoping that ventilated seats would be more popular. Down here in southern TX any car can be like an oven in the summer. Ventilated seats are only recently coming on cars and even then only as a high priced option. I'm not sure of any German mainstream car that has ventilated seats.

 

I'm a former MSF instructor. I forget the details because it's been so long ago but there was a study done and for the motorcyclist it doesn't matter whether the helmet is black or white. The reason is because of the thick foam that lines the shell. It is similar to the insulation used in refrigerators and the heat felt by the rider is no worse in the black helmet than it is wearing the white helmet.

 

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You're welcome! (I apologize that the tone was a little more acerbic than I should have been.)

I agree that the interior temps bit is quite interesting.

There's second way that the hotter dark colors makes sense — not only do they reflect less heat, but their emissivity is considerably higher than light colors, so they will release more of that heat back into the environment more quickly. A matte black will radiate IR the most quickly (all else being equal). From what I've read, metal flakes in the paint, such as are used in the metallic colors MINI offers, lowers emissivity. I'm not entirely clear on why that is, but it might be because the metal reflects some of the heat back into the deeper layers of the paint?

I did turn up a table of emissivity of various paints which is quite interesting:
http://energyexperts.org/EnergySolut...l.aspx?id=4757

I should really grab my IR thermometer gun and go to a car lot and check some temps and get some of my own data.

 

Does the temperature of the paint have anything to do with the air temp inside the car? If you touch the headliner inside a car with a black roof, is it hotter than with a white roof? I have a feeling that exterior paint color has practically no bearing on interior air temperature.

 

All this talk of heat, outside and inside. Let's consider that as hot as the outside and inside get, the A/C cools the interior extremely fast. Likely due, in part, to the small size of the car. Much quicker to cool than my old '11 Buick LaCrosse. Today it was about 92 outside and very humid. I have a dark interior. Got into a somewhat hot MCS, put on the A/C and within a few blocks it was nice and cool.

 

Did I read somewhere that the Minis have an automatic venting system that would suck the
hot air out of the car if it reached a certain temp?

I'm talking about when it's parked in the sun with windows up.
I'm sure I saw that on NAM somewhere. Anyone know about that? If so, is that true of the F56?

 

Sounds like the Parked Car Ventilation System. I believe you need the auto climate system (standard on 2015s). Its covered in the manual on page 132. Has to be turned on and if so will attempt to vent for the next 24 hours.