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We had this discussion over burgers with some friends yesterday. One of our friends admitted to having the a/c button "on" when they wanted hot air.

I always thought the a/c compressor and the heater core operated independently. You only use the a/c button when you want cold air.

They say it makes the heater work faster...and "conditions" the air, regardless of whether it's hot or cold.

No one in the group is a mechanic, so I thought I'd open it up to the board. Why should/shouldn't I have the a/c button on when I want heat?

Cheers,

-Lance
 

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By first cooling and then reheating the air you will in fact dry it or reduce its humidity.

I never do this. In fact I dont even use the climate control, but prefer to switch the aircon on and off as I need it.

I figure this saves me fuel and makes ever hp available for forward motion when I need it.
 

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By first cooling and then reheating the air you will in fact dry it or reduce its humidity.

I never do this. In fact I dont even use the climate control, but prefer to switch the aircon on and off as I need it.

I figure this saves me fuel and makes ever hp available for forward motion when I need it.

True. The air is dehumidified when it passes over the AC condenser. If you live in a humid area it is essential to control the humidity in the interior to extend the life of the interior and keep mold at bay.

Many will find that their windows will fog up very quickly if they turn off the AC when heating in a cold climate... especially if there is water in the cabin from wet/snowy shoes, etc. The warm air picks up the moisture but then condenses on the cold glass.
 

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I drive with my A/C on all the time (except when the moonroof is open, of course) ... just adjust the temp to my liking ... never a problem in over 68,000 miles. Sometimes I have to turn OFF the recirculating air (it is ALWAYS on Auto) due to moisture build up on the windshield.
 

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As mentioned, they are independent systems that can be used together.

While A/C is a cooling system, it is also a dehumidifier.

The heater core is exactly that - a heat exchanger to warm the air.

One note is that you definitely should turn your A/C on at least 1 time per month in the winter in order to keep you seals lubricated.

Like John I never turn mine off.

d-
 
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