The diference is "Black and White"...

[caseydog]

It is 105 degrees on my front porch right now.

I took my infrared thermometer out on my street, and measured the surface temperature of a black car and a white car.

The black car was 163.4 degrees on the surface.

The white car was 135.7 degrees on the surface.

That's a big difference, IMO. Definitely something to consider when choosing a color for the TD.

[Arne]

I 'went white' while on a motorcycle ride. My helmet was black, my g/f's was white. We were waiting for a ferry, and both helmets were out in the sun sitting on the cycle seat. I could barely touch mine it was so hot... her's was luke warm....

When I got home, I sanded my helmet and painted it white.... just like my teardrop. And my last 4 minivans.

[planovet]

I agree, BIG difference. When I was buying my current TV, I really liked the look of the dark blue color. But the interior was dark also and I figured I would go with a lighter color. I bought the pewter version with the khaki interior. I'm glad I did, especially on days like today.

[High Desert]

those are some interesting results CD. I've had light colored vehicles for years now, white, silver, tan, etc. To be honest though the main reason I choose the lighter colors is they don't show the dirt and scratches as bad. But cooler is better too.

a similar interior temp test would be interesting. I'd think it would yield similar results.

[Arne]

it's easy to test outside. when you are in a parking lot, feel the hood of a dark car and the hood of a light/white colored car.

Since there is little around the house or t/d inside that matches the heat of the sun, I doubt color makes any difference.

[Larwyn]

I have a pewter Silverado pick up with a black aluminum tool box. I took the IR thermometer out a few minutes ago and got the following results for surface temps in direct sunlight. All readings were taken at apox the same distance form the ground and on the same plane in relation to the horizon. Ambient temp was from a different instrument.

Ambient temp = 99.2
White painted wood = 132.6
Pewter painted steel = 157.1
Black painted aluminum= 185.7

[High Desert]

it's easy to test outside. when you are in a parking lot, feel the hood of a dark car and the hood of a light/white colored car.

Since there is little around the house or t/d inside that matches the heat of the sun, I doubt color makes any difference.

Quite true. They are fairly well shielded as a rule. I was just thinking more of the car interior temps.

[S. Heisley]

I know inside color on a car effects the temperature. Just touch various color steering wheels when the cars have been sitting in the sun. Black is impossible to touch on a hot day. Both beige and medium blue seem okay. Never had a problem with the white interior on the car I used to have but I had to cover the black seats on my silver car with gray material.

What I'd really like to see is how the outside color effects the inside temperature. After all, many of us carry precious cargo (kids and pets) that might be napping in the trailer during the day.

Buy the way, we're having a heat wave in No. Calif. It's 107 in the backyard right now and expected to get to 108 today. I'll bet it'll be at least 110 by 4:00 PM. Supposed to be triple digits all week.

[caseydog]

I have a pewter Silverado pick up with a black aluminum tool box. I took the IR thermometer out a few minutes ago and got the following results for surface temps in direct sunlight. All readings were taken at apox the same distance form the ground and on the same plane in relation to the horizon. Ambient temp was from a different instrument.

Ambient temp = 99.2
White painted wood = 132.6
Pewter painted steel = 157.1
Black painted aluminum= 185.7

The temperature of the wood surprises me. I wouldn't have guessed that it would be that hot.

You also got higher temperatures on metal than I did, even though the ambient temperature here was higher. I wonder why that happened.

I've never checked my IR Thermometer for accuracy. Maybe it's off. Or, perhaps how/where we measured was different.

CD

[Larwyn]

I have a pewter Silverado pick up with a black aluminum tool box. I took the IR thermometer out a few minutes ago and got the following results for surface temps in direct sunlight. All readings were taken at apox the same distance form the ground and on the same plane in relation to the horizon. Ambient temp was from a different instrument.

Ambient temp = 99.2
White painted wood = 132.6
Pewter painted steel = 157.1
Black painted aluminum= 185.7



The temperature of the wood surprises me. I wouldn't have guessed that it would be that hot.

You also got higher temperatures on metal than I did, even though the ambient temperature here was higher. I wonder why that happened.

I've never checked my IR Thermometer for accuracy. Maybe it's off. Or, perhaps how/where we measured was different.

CD

I see the temps as only relative as I do not know the actual accuracy of the the instruments which I used either. The IR is an Extech, and the ambient thermometer is a Fluke device which converts temp into mV readings. The temp converter was pluged into a Fluek 87 (a very accurate meter). The Fluke is probably more accurate than the Extech but they were used for different purposes. I know with the IR's you get more accurate readings if you you put black friction tape over the surface you are reading (reflectivity?). My readings were taken on bare surfaces, maybe I will try again tomorrow over taped surfaces just for grins. All my readings were taken from vertical surfaces, and close to the same distance from the ground. Unfortunately there is a black logo badge on the pewter surface within the very limited vertical surface of the tool box so the reading was taken a couple of inches higher from the ground than the box. The painted white wood surface was the Escape Pod which was between the sun and the truck but not casting a shadown on the truck. My test was for my information and reference only, no grantee of accuracy.

[Fenlason]

yes the emissivity of an object will affect the readings you get.

[Fenlason]

metal in the sun will feel hotter than wood, of the same temp, just because it is more efficient and transferring that heat to you.

[planovet]

emissivity

Word of the day

[angib]

Hey, it's that time of year again for me to repeat the little I know about this subject - we are having a 'heat wave' in Britain with temperatures as high as an unbearable 90 F, though thank goodness they're only hitting 80 F where I live.....

The pre-air-conditioning solution to this problem featured on Land Rovers intended for use in tropical regions and it's called the 'Safari Roof':



The normal roof of the Land Rover has a second cream (hey that was as white as they could get in the 1950s!) roof above it, so there is a constant airstream between the two that carries away the radiant heat and keeps the Landy's inner roof at ambient temperature. Naturally the near-vertical side windows and windscreen of this old design help with cutting solar gain - but that's one reason that body shape is still used today.

Of course it relies on the movement of the vehicle to work, but a similar system on a teardrop roof supported on pegs would probably work in all but windless days.

And the inexplicable bit is why did they go to all that bother with a safari roof and then put in those curved roof-edge windows for the sun to beat through?

Andrew