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Two tips for a faster cool down

No one is particularly patient when it comes to passenger compartment cool down in hot weather. We’re all impatient in today’s society. We want it now!  So, when the inside of our car is hot we are also cranky. You know how it goes, you start the engine, hit Max A/C and turn the blower up to High expecting to get hit with a blast of icy-cold air. Lots of luck! In most cases, the blast will be something out of a Sahara storm, and it will continue until all the hot air is blown out of the HVAC case.
A few cars have Automatic Temperature Control (ATC) systems that clear the case by directing airflow to the foot registers for a half minute or so, and that helps. But that’s very few cars and doesn’t even include some of the most expensive ones. And what would be even more helpful is if these ATC systems would put the system into a low blower speed as they switch airflow to the A/C registers until the duct air really is cold enough to justify a high-airflow blast. But that doesn’t happen either.
Improving cool down is not as simple for the manufacturer as just putting in a big compressor, bigger or more efficient heat exchangers, etc. Sorry, but there are limits, set by budget issues, space available, and power available to run the system. And duct shape also is an important contributor to cool down, particularly for rear-seat passengers.
If you’re experiencing a hot summer, you may complain about how slow-to-cool, your car A/C system is.
Here are two  tips to get the cooling job done a little more efficiently:

  1. If the vehicle has been in a hot soak, for example, run the system in Manual/Floor mode first to clear the HVAC case of hot air. Do this with the windows open so the hot air exits the passenger compartment. Then switch to Max A/C, but with the blower on low speed. The amount of airflow may be modest, but it will be at a lot lower temperature.


  1.  If the car can be parked in a safe area, leaving the windows partly open and sunroof ajar can reduce the heat buildup in the cabin. If that’s not feasible, and hot soak is a real problem, ask your service professional about the installation of a solar-powered vent fan, which should purge the hot air sufficiently.

When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.  
You can E-mail us at or visit to find a Mobile Air Conditioning Society repair shop in your area. Visit to find out more about your car’s mobile A/C and engine cooling system.

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