I think some cars fog up naturally but if ianzin would give us the make , model & year of the car perhaps we could check what it may be, after all, its only three years old, thats too early for a heater core on a Toyota to be doing this, i would think.
Perhaps it depends upon the car. That’s certainly not always true, according to the car manual.
GaryT, I was meaning to ask about that… why would it be so bad to use recirc on heating functions? I’ve done it in my car for limited periods of time to get the temp up quicker. The windows do tend to fog pretty easily, which is why I always turn it off eventually.
The recirculate feature was designed to reproduce one feature of the old under-the-dash auto air conditioning units, which was that they drew inside air, which had already been cooled. Obviously, this results in colder output from the A/C than drawing outside air on a warm day.
Most American cars have a “Max A/C” feature which differs from the regular “A/C” in that it engages recirc. On these systems, recirc is not available in any other mode.
You don’t want recirc in “Vent” because the whole point is to get ventilation, i.e. outside air.
You don’t want recirc in “Defrost” or “Heat” because it works against defogging by keeping all the moisture in the car. No matter how humid it is outside, it will get still more humid inside because of the moisture from breath and perspiration. Recirc makes the fogging worse.
While automotive A/C has a struggle to get cold, and can use the help of recirc, a properly working auto heater has a large supply of engine heat to work with, and can roast you out of the car. There’s no need for recirc on heating functions.
Some owner’s manuals might not instruct you to limit recirc to A/C, I’d be very surprised if any specifically tell you to use it with venting or heating functions.
It may be that the inside will warm up a bit more quickly using recirc with the heat, and you may certainly choose to do it that way if it suits you. But most folks won’t notice the difference, and aren’t inclined to have one more control feature to mess with and think about, hence my recommendation to not use recirc with heat.
If the condensation on the window was due to a bad heater core, car would smell of coolant. Nowhere does OP mention an odd smell. Furthermore, there are potentially lots of chemicals in the interior of a car that could give the moisture an oily consistency.
I bet this problem is caused by either a leak, e.g., around the glass of the windshield, or a clogged body drain.
I would not recommend using a stop leak additive in such a new car for any reason.
Well, found this on the net too:
"When I switch on the fan and the heater to demist a slightly misted front window the hot air is obviously coming through very heavily moisture laden as first of all the windscreen becomes completely misted, pure “white out” so I have to stop driving.
Answer:
"To remove interior fog on the windshield.
1 Place temperature control lever to any position
2 Move the air intake control lever to the OUTSIDE AIR position
3 Move the air flow control lever to the WINDSHIELD position
4 Move the fan speed control lever anywhere EXCEPT the off position
5 Press in the air-conditioning on-off button
I find this works and as the engine warms the air-con. can be turned off and warm air introduced."
handy’s post illustrates that engaging the A/C compressor helps in defogging. This is because the A/C dehumidifies the air. On most American cars, the “Defrost” position automatically engages the A/C for just this reason. On cars with a separate pushbutton for the A/C, you have to do it yourself.
With a properly working heater, it should produce enough heat that you don’t need to turn the A/C off unless you want to.
my car fogs up from the inside, too.
i got some Fog B Gone cloths at the car shop and it works like a charm!
also, the seat feels a little wet sometimes (eww)
my car has problems.