Help settle this argument - Hot A/C

[theblackkeys]

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If you have the knob turned all the way over to the hottest setting, and you hit the "AC" button, the air does not get colder, and will not get colder, until the knob is turned to the cooler side.

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I would be shocked to find a car that does not fit the above.

AC dehumidifies the air (anytime you are using the defogger your AC is activated), it won't change the temperature. In my Toyota the AC light comes on whenever the defog is on and I get so annoyed when ppl say "Why in the world do you have the AC on? LOLZ"

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serious question: why does the air get colder when you are on the cold setting + AC? Clearly the air is not very cold if you just set it to the coldest setting without AC (air just comes straight in from the outside basically)

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? I'm not really sure where you're trying to go with these questions. Refrigerants make the air cooler. I imagine the AC system doesn't use the refrigerants when the temp setting is on high, and just uses engine heat to warm the air. Of course, I have no idea what I'm talking about, just pulling this out of my ass.

[ImAKing]

the A/C means nothing to the temprature of the air blowing out. A.C is jsut if the air more dry. Temp to hot and A/C on= temp still hott

[dknightx]

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the A/C means nothing to the temprature of the air blowing out. A.C is jsut if the air more dry. Temp to hot and A/C on= temp still hott

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the problem with this is that unless you turn on the "A/C", the coldest setting will only be as cold as the air outside ... drying the air outside does not make it cold.

[Osprey]

I would guess there's a compressor element to the car A/C along with a refrigerant/heat exchanger element. When you need dry hot air, you probably just compress it and pump it into the cabin. When you need cold, dry air, you probably compress it, and also pass it over some kind of heat exchanger/refrigerated core. I think that's the difference.

[d10]

AC dehumidifies air by making it colder. Everyone saying their AC does have dehumidifying effects no matter what the heater is set to must agree that at some point the air coming into the cabin is made colder than the ambient temperature.

If you believe the temperature coming out of your vents remains the same with AC on or off, the argument must be that the air is heated back up again before it gets there. The only heating element after the AC's evaporator (the component which cools/dehumidifies the air) is the heater core.

In every car I'm familiar with, the heater temp control will regulate a specific amount of coolant flowing into the heater core. It doesn't care what the outside temperature is or whether the AC is on. In that case there's no way the heater can heat colder, air conditioned air to the same temperature as warmer ambient air.

I don't know how these newer cars work. It's possible that there is some kind of system in place these days that will force the heater core to heat air to a specific temperature before passing it through the vents.

[GuyOnTilt]

I keep the A/C on all the time in my car. It definitely does not decrease the temp when you have your heat on, just dries out the air so your windows won't ever fog at all on the inside.

[d10]

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I would guess there's a compressor element to the car A/C along with a refrigerant/heat exchanger element. When you need dry hot air, you probably just compress it and pump it into the cabin. When you need cold, dry air, you probably compress it, and also pass it over some kind of heat exchanger/refrigerated core. I think that's the difference.

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AC doesn't compress air.

[Osprey]

Well then, what does the A/C compressor do? I am just guessing, but I assume it compresses air, and compressed air doesn't hold moistore as well as less dense air. And cold, ldenser air really doesn't hold moisture as well as hot, uncompressed air.

[d10]

The compressor compresses freon to make it hot, allowing the ambient air to cool it when it passes through a condenser. Then the compressed/cooled freon is allowed to expand, making it colder than it was before it was compressed and it passes through the evaporator. AC makes cold air by passing through the evaporator. The dehumidifying effect of AC is a byproduct of cooling the air, since cold air can't hold as much water.

[Osprey]

That seems.... quite plausible. Food for thought...