# Black cars and summer heat **URL:** \ **Category:** Factual Questions\ **Created:** [May 31, 2016, 3:52pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169 "2016-05-31T15:52:23Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 31, 2016, 9:47pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/21 "2016-05-31T21:47:49Z")
And it sometimes helps to have a hatchback. If I spend a few minutes loading stuff into my car, it’s enough time for much of the heat to escape before I get in and drive. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [May 31, 2016, 11:21pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/22 "2016-05-31T23:21:59Z")
> [@panache45](#): > > And it sometimes helps to have a hatchback. If I spend a few minutes loading stuff into my car, it’s enough time for much of the heat to escape before I get in and drive. OTOH, the problem I had with having a hatch back is that from time to time I’d have (plastic) things melt in there that I never had a problem with in my trunk. Of course, the ultimate solution is to have a garage. Blazing heat or a foot of snow and your car is still ready to drive. ---
**Author:** ![JerrySTL](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@JerrySTL](https://boards.straightdope.com/u/JerrySTL)\ **Post date:** [June 1, 2016, 12:19am UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/23 "2016-06-01T00:19:00Z")
I put a reflective shade in the front window and try to point the car where the sun will be when I get back into it. It does make a difference especially when grabbing the black steering wheel. Ouch! I also have vent visors on the front door windows so that I can keep the windows down an inch or so and not have to worry about rain. The vent visors seem to work best if there’s a cross wind blowing through the windows. Of the two, the reflective shade works best. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [June 1, 2016, 12:58am UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/24 "2016-06-01T00:58:59Z")
> [@Joey\_P](#): > > This reminds me, if you have a Honda, many of the newer ones have a trick where if you hold down the unlock button on the key fob all the windows will go down. Really, really annoying, I wish there was a way to turn it off since holding down the lock button doesn’t roll them all back up. If you do it by accident you have to close each one, including the sun roof, if you have one. VW had a similar feature awhile back,[with a funny commercial](https://www.youtube.com/watch?v=CttdIFVusqg) where a nerdy guy reads about it in his new car’s owner manual and then eagerly shows it to his wife, who couldn’t care less… ---
**Author:** ![dougie\_monty](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dougie\_monty](https://boards.straightdope.com/u/dougie_monty)\ **Post date:** [June 2, 2016, 3:00pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/25 "2016-06-02T15:00:38Z")
…a cat rather than a car. Our cat Archie, of the Sixties, who was colored like the Clinton’s cat Socks or Sylvester of the cartoons, had fluffy fur. He probably disliked the heat of summer as much as we humans–although I don’t know how that works with cats, whose body temperature is three degrees higher than humans’. He seemed to know where all the shady spots were outside; he often stayed in a clump of bushes near our driveway that we called his “jungle.” 🙂 ---
**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\ **Post date:** [June 2, 2016, 4:36pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/26 "2016-06-02T16:36:52Z")
An anecdote that someone might be able to explain. When I was a paper-boy, the weekly collection for the paper delivery was 45c, and in those days, coins were made of silver. Some customers would just leave the 45c on the porch on collection day. Coins in direct sun for a few hours were too hot to touch. Why would the shiny silver surface absorb, rather than reflect, so much of the solar energy? ---
**Author:** ![troub](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troub/32/14802_2.png) [@troub](https://boards.straightdope.com/u/troub)\ **Post date:** [June 2, 2016, 5:20pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/27 "2016-06-02T17:20:12Z")
Shiny or not, if it’s in the sun it will eventually come to absorb enough to become hot. It may even simply reach the same temperature as the concrete (or wood, or whatever) of the porch, as well, though note that you may not feel _that_ surface is too hot to touch. Metal is generally a good conductor of heat, so it may feel hotter to you when you touch it as it more quickly transfers that heat to your hand. ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [June 2, 2016, 6:21pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/28 "2016-06-02T18:21:25Z")
> [@jtur88](#): > > An anecdote that someone might be able to explain. When I was a paper-boy, the weekly collection for the paper delivery was 45c, and in those days, coins were made of silver. Some customers would just leave the 45c on the porch on collection day. Coins in direct sun for a few hours were too hot to touch. Why would the shiny silver surface absorb, rather than reflect, so much of the solar energy? The reason the coins felt too hot to touch may have had more to do with the coins’ thermal conductivity rather than their emissivity. I know Pre-1965 coins weren’t pure silver, but silver does have the highest thermal conductivity of any metal so it can transfer heat to your hand very effectively. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [June 2, 2016, 6:46pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/29 "2016-06-02T18:46:18Z")
> [@jtur88](#): > > An anecdote that someone might be able to explain. When I was a paper-boy, the weekly collection for the paper delivery was 45c, and in those days, coins were made of silver. Some customers would just leave the 45c on the porch on collection day. Coins in direct sun for a few hours were too hot to touch. Why would the shiny silver surface absorb, rather than reflect, so much of the solar energy? Metals have lowish **specific heat capacity** - they can’t “hold” much heat energy, so a small energy input/output corresponds to a large temperature change. Thus, for a given amount of sunlight absorbed (i.e. comparing two things the same color) a metal coin will heat up more quickly than (say) soil. > **[Heat capacity](https://en.wikipedia.org/wiki/Heat_capacity#Table_of_specific_heat_capacities)** > > Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K). > Heat capacity is an extensive property. The corresponding intensive property is the specific heat capacity, found by dividing the heat capacity of an object by its mass. Dividing the heat capacity by the amount of substance in moles yields its molar heat capacity. The v... Metals also have a very high **thermal conductivity** - heat “moves around” within metal easily. Thus, if you compare touching a hot metal to a hot [anything else] at the same temperature, the metal will give you a more severe burn. With [anything else], only the heat in the surface layer is conducted to your skin; with a metal, the heat from the entire object is rapidly transferred to your skin. > **[Solids, Liquids and Gases - Thermal Conductivities](https://www.engineeringtoolbox.com/thermal-conductivity-d_429.html)** > > Thermal conductivity coefficients for insulation materials, aluminum, asphalt, brass, copper, steel, gases and more. ---
**Author:** ![dougie\_monty](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dougie\_monty](https://boards.straightdope.com/u/dougie_monty)\ **Post date:** [June 2, 2016, 10:46pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/30 "2016-06-02T22:46:41Z")
> [@Surreal](#): > > The reason the coins felt too hot to touch may have had more to do with the coins’ thermal conductivity rather than their emissivity. I know Pre-1965 coins weren’t pure silver, but silver does have the highest thermal conductivity of any metal so it can transfer heat to your hand very effectively. They were 9 parts silver and one part copper. On a scale of 1 to 100, with silver being at 100 as the best conductor of heat, copper comes in second-best at 95. (Source: Isaac Asimov.) That would make for mighty warm coins, I’d say. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [June 2, 2016, 11:42pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/31 "2016-06-02T23:42:37Z")
A/C??? Seems to work well with my black car, white car, red car, tan car, blue car (which I never really had - but anyway), silver car. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [June 3, 2016, 12:42am UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/32 "2016-06-03T00:42:33Z")
I had to drive a black car with a black car for a year in the Sonora desert, and the parking lot at work had no place at all for shade. The _only_ thing that ever gave me relief was covering the steering wheel with a white towel during the day, otherwise I literally would be unable to grasp the steering wheel enough to drive safely. (We weren’t allowed to crack the windows on company-owned cars, unfortunately, due to high levels of property crimes in the area.) So much radiated heat would build up that the air conditioner took about 30 minutes to catch up. It was only a 25 minute drive home. I never did figure out who the hell thought it would be a good idea to order black cars in Sonora. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [June 3, 2016, 12:52am UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/33 "2016-06-03T00:52:52Z")
It surprises me when renting cars in desert areas that agents don’t understand immediately why somebody would want a light colored car. A couple of times I’ve had a car rental agent look at me askance when I’ve said I don’t want a black car. I’m pretty sure they thought I was a racist. But I can’t be, right? After all, some of my friends have black cars. ---
**Author:** ![dougie\_monty](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dougie\_monty](https://boards.straightdope.com/u/dougie_monty)\ **Post date:** [June 3, 2016, 4:01am UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/34 "2016-06-03T04:01:51Z")
> [@Riemann](#): > > It surprises me when renting cars in desert areas that agents don’t understand immediately why somebody would want a light colored car. A couple of times I’ve had a car rental agent look at me askance when I’ve said I don’t want a black car. I’m pretty sure they thought I was a racist. But I can’t be, right? After all, some of my friends have black cars. I wonder what color cars did the agents themselves drive. ---
**Author:** ![rock\_party](https://avatars.discourse-cdn.com/v4/letter/r/e19b73/32.png) [@rock\_party](https://boards.straightdope.com/u/rock_party)\ **Post date:** [June 3, 2016, 8:21am UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/35 "2016-06-03T08:21:00Z")
There’s a huge opportunity for someone who figures out how to keep cars cooler in the summer. Kids and pets wouldn’t have to die anymore, and your hands and butt wouldn’t have to burn. I think maybe if the roof and hood were solar collectors there would be enough power to keep the interior below say 90 degrees, cool enough so you could take kids and pets without accidentally baking them. ---
**Author:** ![SpeedwayRyan](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@SpeedwayRyan](https://boards.straightdope.com/u/SpeedwayRyan)\ **Post date:** [June 3, 2016, 8:00pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/36 "2016-06-03T20:00:04Z")
> [@jjakucyk](#): > > Also about window tinting, does anyone know how much of a factor that is? I’m curious because while the tinting may block sun from heating up the objects that it hits inside (seats, dash, consoles, etc.), it also makes the glass itself hotter, acting sort of like a radiator. I’d rather get a low-e coating like they put on building windows since it’s designed specifically to reflect heat, and I’m not personally interested in tinting itself. Pretty substantial. The link below has some specifics, but 50%+ heat rejection is common. You can get clear tints that reject heat, BTW, if interested in keeping the interior cooler but not in the look of tinted glass. [http://w3.llumar.com/skinprotection/discover-cool.html](http://w3.llumar.com/skinprotection/discover-cool.html) ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [June 3, 2016, 8:10pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/37 "2016-06-03T20:10:24Z")
> [@kanicbird](#): > > A/C??? Seems to work well with my black car, white car, red car, tan car, blue car (which I never really had - but anyway), silver car. Running it 24/7 must play hell with your mpg. ---
**Author:** ![Hayden](https://avatars.discourse-cdn.com/v4/letter/h/91b2a8/32.png) [@Hayden](https://boards.straightdope.com/u/Hayden)\ **Post date:** [June 3, 2016, 8:43pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/38 "2016-06-03T20:43:01Z")
This. Tint is the best way to reduce interior heat and makes a big difference. A ceramic film generally provides the best heat rejection, but even a quality non-ceramic film will help a lot. > [@SpeedwayRyan](#): > > Pretty substantial. The link below has some specifics, but 50%+ heat rejection is common. You can get clear tints that reject heat, BTW, if interested in keeping the interior cooler but not in the look of tinted glass. > > [Películas arquitetônicas e automotivas para vidros e PPFs | LLumar](http://w3.llumar.com/skinprotection/discover-cool.html) Sent from my iPhone 6 using Tapatalk ---
**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\ **Post date:** [June 3, 2016, 10:05pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/39 "2016-06-03T22:05:11Z")
> [@Riemann](#): > > Metals have lowish **specific heat capacity** - they can’t “hold” much heat energy, so a small energy input/output corresponds to a large temperature change. Thus, for a given amount of sunlight absorbed (i.e. comparing two things the same color) a metal coin will heat up more quickly than (say) soil. > [Heat capacity - Wikipedia](https://en.wikipedia.org/wiki/Heat_capacity#Table_of_specific_heat_capacities) > > Metals also have a very high **thermal conductivity** - heat “moves around” within metal easily. Thus, if you compare touching a hot metal to a hot [anything else] at the same temperature, the metal will give you a more severe burn. With [anything else], only the heat in the surface layer is conducted to your skin; with a metal, the heat from the entire object is rapidly transferred to your skin. > [Solids, Liquids and Gases - Thermal Conductivities](http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html) So, applying this to the OP, would a metal car transmit exterior-sourced heat to its interior space more efficiently than, say, a plastic or fiberglass car, and therefore be hotter inside?? ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [June 3, 2016, 10:24pm UTC](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169/40 "2016-06-03T22:24:40Z")
> [@jtur88](#): > > So, applying this to the OP, would a metal car transmit exterior-sourced heat to its interior space more efficiently than, say, a plastic or fiberglass car, and therefore be hotter inside?? Other things being equal, yes. I don’t know much about cars - is there usually an insulation layer of some kind inside the panels? [Previous page](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169.md?page=1) [Next page](https://boards.straightdope.com/t/black-cars-and-summer-heat/756169.md?page=3)