My car is black and I live in Australia. When I go to buy groceries it gets unbearably hot inside the car (especially in summer).

Black Car

Is there a quick way to cool down my car so that I don't have to blast the air-con or wait for 10-15 minutes?

  • 1
    @ajaxkevi questions are similar but not duplicate because my air con does work, i want alternatives that cool down my car instead of blasting the air-conditioning.
    – Darren
    May 4, 2015 at 8:41
  • the question does provide details about not having aircondition
    – Kevin
    May 4, 2015 at 8:55
  • Leaving the windows open, if just a little bit, will keep the car from getting as hot in the first place. If opened just a little bit, it will not be easily detected but still function quite well.
    – holroy
    May 5, 2015 at 23:42

5 Answers 5


There are two hot things to deal with: SURFACES and AIR

AIR has pretty much one best solution, exchange the air. Opening one door can take a long time if you're just waiting passively for the air to covect out. You can actually see the hot air if you look on a hot day for the air shimmer or (even cooler) watch the shadow of the door you've opened. If you have passengers opening the passenger side the smart thing to do is coordinate opening your door before they get in and leave it open as they enter, this gives air time to enter from the windward size and exit from the leeward. You can turnover the air in a car in a few seconds with even slight wind this way and if you're sly about it the passenger may never know. I do this a lot. If it's just you getting into the car it's a little tricky to open opposing doors. One possibility is to have a door and sunroof open to get crossflow but if it's a power sunroof opening it can take too long and put strain on your battery. If you are alone and have no convenient sunroof then you may have to resort to the old "swing around a magazine" approach or some other inelegant way to move the air although since you're alone in this case nobody should see :)

SURFACES are harder to cool because they have both more thermal mass and lower thermal dissipation (air is an insulator but convection actually exchanges the air which increases cooling speed by factors of 100). My usual solution for surfaces is to pick a couple important ones and change the surface into something that doesn't gather or convey heat to the user as well. This is a good reason for wood steering wheels or certain types of steering wheel and seat covers. Choices all depend on your preferred looks and textures as well as which surfaces get hot enough to be worth fixing.

There are a lot of fine variations here (like maybe a small battery fan to move the air). I look forward to useful additions in the comments.

  • Related suggestion for moving the air out: open the driver's door, then walk around and open-close-open-close-open-close the passenger's door. Make your own wind! May 4, 2015 at 18:52

I have some Ways that you May Like...

1. Most Efficient: Slamming Car Doors from One Side

Open all the doors on both the sides.
Keep the window up. Now grab both car doors on one side and get ready.

Now slam and close the doors as fast you can.

All the hot air will gush out in that action.

Works at once. But repeat for better results.

2. Avoid Heating Up using Sun Screens

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3. solar-powered car exhaust system

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4. Best way is to Find shaded parking


There are solar powered fans that will circulate air through your car without draining the battery. Not sure how well they work.

You should also be using one of those reflective screens inside the windshield - they're a bit of a hassle to put in and take out each time you park, but worthwhile just in keeping your car interior from deteriorating prematurely.

You could also try to park in the shade, or go in the evening.

As far as cooling the car down quickly, simply rolling the windows down and driving for a few minutes is probably the most efficient way to do it. The car will get a lot hotter than the air outside, even on a hot day.


Carry a spray bottle of water. Before getting into the car, spray all the surfaces, especially the ones you'll touch, with water and let it evaporate. Repeat until the surface is cool. And while driving, you can occasionally spray yourself...

And next time, buy a white car.


Use a magazine or (better) sheet of still board held at angle in air stream as an air deflector - 45 degrees or so from forward facing with leading edge into wind while driving works wonders (This may or may not violate Oz regulations :-) ).

In the days of "quarterlights" the same effect was achieved by rotating them about 135 degrees from closed so the blunt front edges protruded into the air flow.
And it makes YOU cool immediately while the car interior follows. |

Small solar powered window fans do not have enough airflow in hot sun - even in NZ. Ask me how I know. Something I haven't tried but intend to is to enable either the airconditioning fan or a suitably larger in-window unit to get useful air changes. Battery life needs watching.

Leaving all windows somewhat down works quite well. This adds a security hazard. I've seen lock-in grills that provide substantial open spze and which slot over window glass and into top of frame. Wind down - insert-wind up to lock in place. Probably very effective.

Tasteful foil covered whole of windscreen fold out sheets have their place. try this: Stand somewhere say 1 floor up as close to vertically above car as possible. Look down onto car. Be amazed what % of total projected looking-up area is in glass. I'd guess at over 50% in the car you show above. Effectively reducing that area with window screens is going is going to help.

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