I have a 2004 Santa Fe LX 4WD 3.5 L.
When it is cool outside (say 55 to 65 degrees F), and my vehicle has been
sitting in the sun, I like to be able to just have cool outside air coming
in to cool the car off while I drive. Of course, I can open one or more
windows to let cool air in but I would rather have cool air coming in
through the vents -- it's much quieter that way. What I do is set the
temperature to "lo", set it for outside air, set the mode for dashboard
vents only, and turn on the fan.
But, no matter what I do, the air coming in through the vents is not cool
like the outside air that comes in through an open window. It's not hot,
just vaguely luke warm at most, but definitely not cool and not the same
temperature as the cool outside air. Am I doing something wrong or
expecting it to do something that it cannot do?
Of course, I could turn on the AC but I don't want to do that since the
outside air is already cool.
The last half dozen car I've owned (various makes) were like that. The vents
travel through areas that seem to be warm and the vent air is never the same
as the straight outside air. I just use the AC as it does not affect fuel
mileage very much these days like 25 years ago.
That depends a lot on the particular car in question. The A/C cost me at
least 3 mpg on the highway in my Elantra. On one of the Elantra sites,
someone did dyno runs with and without A/C. The A/C cost him 17
horsepower! Judging by the way the car reacts when I turn it on, that
seems entirely plausible. It makes sense that it's less of an issue with
cars that have more powerful engines and get lower mpg to begin with,
but it still costs you.
As for the windows down vs. A/C debate, it all depends on the particular
vehicle in question. Some may do better with the A/C on, but my Elantra
does better with the windows open.
BTW, I've found a method that works very well for cooling the car,
without excessive noise or drag. I tilt the sunroof open, open the rear
passenger's window 1/3-1/2, then open the front passenger's window
2"-3". This creates a swirl in the car's interior that cools very
effectively, even at modest speeds. The windows can be opened or closed
to regulate the amount of airflow. I can still listen to the radio
comfortably, as I don't have the noise from having the driver's
I don't have a sunroof, but if I did I wouldn't want to have to open the
sunroof or anything else just to get cool outside air into the car. I have
a hunch that even at the lowest temperature setting there is still some hot
water going through the heater core and partially heating the incoming air.
Why not, that's what it's for. I didn't say that it was mandatory
(obviously you wouldn't use it if it was raining), but it does increase
airflow through the car when using the vents, since it gives the
incoming air an easier exit point. It also lets out the warm air near
No, there isn't. The issue is heat from the engine compartment and sheet
It is my understanding that the fuel savingis speed dependent. At low
speeds drag is les than the air conditioner uses. At speed somewhere
above 30 MPH the air drag drom the open windows uses more fuel than
the air conditioner. As they say, YMMV.
Does it get cooler after a few minutes? All cars I've owned have acted
this way after sitting in the sun. Basically, the car gets heat soaked
in the dash and cowl area where the air intake and ductwork is located.
When you first start out these warm components preheat the incoming
cool air. However, most of my cars will being to deliver air closer to
ambient temperatures after a few miles of driving, but it certainly
takes a little while to cool things off. I generally use the AC for a
few minutes to cool down the ductwork and then switch to outside air.
I also usualy leave the ac on for a few minutes & if it was real stuffy
just tilt the sunroof for a while too. I want to ask something slightly
related though a bit off track>
I have read here that it is best to not use the recirculate feature
with the ac to prevent the forming of mold or something which ends up
causing a stink... However quite a few people I have traveled with tell
me it is best to use recirulate rather than breathe the polluted
outside air? I guess it may be true for cities though won't we
breathing the same air we breathe out???
Exactly. You have a choice between interior pollution and exterior
pollution. The interior air filter will remove most particulate matter
(the Elantra doesn't come stock with this filter, you have to install
it), but it won't remove chemical pollution. You could make your own
filter element using filter media with carbon in it, but it's debatable
how effective it would be.
No, but I know what you mean. I keep expecting that it will get cooler but
it never does. I have a feeling that something in the system isn't allowing
the heat function to completely turn off. If I had a manual control, I
would move the heat control all the way to the coolest position. In every
car I've ever owned, when I did that only cool or cold air would come out.
This seems to be functioning the way it would if a manual control wasn't
turned all the way to the coolest position.
It's possible that you car is malfunctioning. There should only be a few
degrees difference between inside and outside air temps when the heat is
off. It sounds like you need to take the car to the dealer.
Ahah! I just figured it out today!
To do what I want, I set the temperature to "Lo", which is one click below
the lowest actual temperature option of "63 degrees". That automatically
turns ON the AC, which I do not want, and the "recirculate inside air"
option, which I also do not want. Then I turn OFF the AC, and I switch from
the "recirculate air" setting to "outside air". That lets outside air -- at
whatever temperature the outside air is -- come in through the vents without
ANY preheating. That's what I wanted. And I don't have to open any windows
or sunroof to get non-preheated outside air in, which is also what I wanted.
If I click the temperature setting up just one click, from "Lo" to 63
degrees, I can immediately feel that the incoming air is being preheated. I
think it does that because, if the outside air is say 55 degrees, and it
thinks I want 63 degrees inside the vehicle, it naturally starts to preheat
the outside air to help bring the inside vehicle temperature up. But, by
selecting "Lo", it is not governed by any specific temperature setting, so
it COMPLETELY turns off the preheating of the air that is coming in. It
seems to work in the same way that a manual heater system does when moving
the temperature setting "off".
That makes sense. It would be interesting to see what the actual
temperatures are and if it does rise anyway on the path through the ducts.
Even on cars with no automatic AC, or even no AC, it always seems to have a
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