As others have said, no, that’s not how it works. The liquid converts to gas by absorbing heat, not ‘at a certain temperature’. Absorbing heat makes the air colder, not warmer.
We’ve owned all Asian vehicles since the mid 80’s and not one turned the AC on when defrost was on. I’ve seen cars that do. But none that I’ve owned. Not sure what the percentage is.
I’m sure the Asian cars, if any, you own today do.
This is an air conditioner, not a heat pump. The compressor turns the gas to a liquid, making it very hot. It goes through the condenser, radiating some of that heat. Then it goes to the evaporator where it expands making it much colder and absorbs heat from the air passing through it. It does not get warmer than ambient.
I’ll take it a true medium-rare, pink with some red in the middle, baked potato, vegetable of the day, and a glass of shiraz after a bourbon aperitif.
Nah, most people don’t realize it. Many times when informing a customer of a needed AC repair when the weather warms up, they ask “Why would the AC not work after not being used all winter?” I explain that the compressor has been running all winter anytime the defroster or heat/def blend has been selected.
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It’s a 1998 Honda Civic. Are you saying it’s impossible to run the fan with the air blowing on the inside of your windshield without running the air conditioner? Your controls don’t have an A/C button?
At a basic level, an air conditioner is a heat pump. It pumps the heat out of the car. The refrigerant is the medium that carries the heat out of the car.
Whether it’s a car air conditioner or a home air conditioner, it uses the same basic principles. https://www.youtube.com/watch?v=JIy8SZwSqiI
I think you’re confused because you’re over-analyzing how the refrigerant behaves. When the refrigerant absorbs the heat in the evaporator, it turns from a liquid into a gas (which is why we call it the evaporator). When the refrigerant goes out to the condenser, it is re-compressed into a liquid, which releases the heat energy the refrigerant carried out of the car/house from the evaporator.
In pretty much every car I have ever driven or tested the heater air can be directed to the windshield. It uses the same icon as the defroster. Simply direct the air (with temp set to hot) to that location if you prefer that it not be coupled to AC. As many have said above, the AC is not doing you any harm in cold conditions, but I understand you want to avoid it. Until the car is warmed up a bit the air being directed to that location doesn’t do much. Once it is warm, you don’t need the AC much anyway since the warm air is very dry in cold conditions. You will find that most cars can also couple the air to the windshield and also to the footwells at the same time. This works well in cold and damp conditions because much of the moisture besides your breath is coming into the vehicle on your boots. When you buy your next vehicle look for one with the small grid of heating elements in the front glass. You will love it. That starts to defrost the glass immediately in cold conditions. Subaru and many premium brands often offer this. I will warn you to avoid the brands like Jag Land Rover that put that grid in the entire glass area. It is hard to see through at night. Just get the ones that have the defroster grid down low. Helps keep your wipers from freezing up in winter too.
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I’m hoping my AC lasts through the winter as I currently have a slow leak and I forgot that the defroster uses the AC. I’ve been told that the compressor won’t get damaged if the AC runs too low as the change in pressure should prevent the clutch from engaging. Although, I’m not sure if the loss of refrigerant which contains the lubricant for the system will possibly damage the compressor during the time the defroster is run. Perhaps I should get it recharged right away? Just not sure if in the process of discharging and recharging the system that if the machine they use determines it won’t hold the charge if they just leave it completely discharged until it’s fixed??
There is a low pressure switch which doesn’t allow the compressor to run below around 30 psi in the system. When you have it diagnosed in the spring, they will determine where the leak is. If it’s in the high side, or if a major component has failed, they may need to add oil. Make sure it’s a shop known for working on A/C systems.
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As long as you’re getting outside air (not recirculating), you probably won’t need the AC. My car hasn’t had AC for about a decade, and I live in Florida. The worst part is the downpours, which often lead to humidity build-up on the inside of my windshield. I’m usually left with the choice of rolling down the windows and getting wet or pulling over because I can’t see though the windshield. I’ve mitigated the problem by installing these, which allow me to open the windows a couple inches without getting water in the car.
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I still have ice on the windshield to contend with which I can overcome by just letting my car heat up, but that’s not always possible.
davies767 . . THAT is normal . .completely normal .
On my old '80 Bronco . . .
I put a toggle switch for the a/c clutch circuit to help a persistent stalling problem.
During the time lag till that was fixed . .
I was able to see the absolute first hand properties of needing the compressor running during defrosting.
– to reiterate . . . I discovered . . first hand . . that you DO IN FACT need the compressor running to defrost ! - -
With it off the defrosting warm air would CAUSE actual moisture ( not frost, . moisture, water, dripping, running down ) to form on the inside of the windshield !
Five minutes later . . turn the compressor ON while defrosting ?
voila ! moisture dries and all defrosting is as normal.
Five minutes later . . just to test the theory . . turn OFF compressor . . . .
. . . . .
moisture returns !
The de-humidifying properties of having the compressor running during defrosting. . .
have . .
NOTHING . . to do with cooling !
just turn to defrost mode and let the car do what it was designed to do !
Even with the system set to bring in fresh air, there’s a bunch of moisture in the car in the winter. The source? Your breath. Along with the melting snow on your boots. But your breath is there immediately, and continuously.
This is from a person who has access to actual facts. Listen to him and let the car do it’s thing.
Maybe you don’t need to worry about the A/C, but it might depend on you and your car.
My past experience living in the PNW (rainy about 8 months every year) with a car with no A/C showed that defrosting the front windshield works with heated air.
It will probably take longer, means more warm (or very warm) air blowing up against the inside of the windshield and then generally in the direction of your head, and is probably affected by the slope of the windshield on airflow.
And you’d be wrong.
Wife has 07 Lexus and I own a 14 Highlander. Neither one turns the AC on automatically when defrost is on. My Sons 11 Mazda 3 does though.
Correct. That’s exactly what I’m saying. Two of my cars have a separate AC button, two of them have rotary knobs. But that’s beside the point. When DEF is selected, the AC compressor runs, regardless of whether you have AC selected or not. Don’t believe me? Go turn on your DEF and see if the AC compressor cycles on and off.
@MikeInNH has the same experience. The AC indicator does not turn on when DEF is selected but the compressor is on. That’s directly from the factory service manual describing operation of a '14 Pathfinder.
NO…that is not what I’m saying.
First off - I don’t have a 14 Pathfinder. I have a 14 Highlander.
And I can turn the Defrost on without turning on the AC. The light is not on and the AC is not working. Verifiable. When I turn the AC there is a significant difference between the AC being on and when the AC isn’t on.
The Highlander owners manual states that you should switch on the A/C for more effective defogging when using the defroster. The A/C operation is automatic with the defroster on with the ES350 as stated in the owners manual, I went outside and tested one.