First Winter Question

What I'm saying is any time the AC is running, ie: the system's chilling the air, you're getting a build up of moisture on the cooling fins of the AC system. Like beads of water on a cold glass. That's the nature of AC systems: they cool the air and extract humidity.

Now, if and when you turn the AC off, there'll be a dump, all that accumulated moisture starts evaporating back into the air. Then you'll get fogging, for maybe the next 15 minutes.

 

... and human respiration releases a significant amount of moisture, from lungs and skin.

... and don't forget that the front defroster also makes use of this AC system.

 

The manual says to NOT use the front defroster - - something about high humidity. I think this is a design problem and needs to be raised to Toyota.

 

I have NEVER had this happen, over many makes of cars and trucks. Fog, sure. Not ICE.

 

The manual states on page 244. Do not use the defogger during cool air operation in extremely humid weather. It does not tell you to not use the defroster.

 

Where i live, i have to plan on a few extra minutes in the morning in the winter time. Summer you can jump in and drive off for work. In the winter, it takes a few minutes to clear the windows of snow or ice that might have fallen the night before. This process is not a waste of time. Just the cost of living in a cold climate. Maybe a small waste of gas. I dont think so but i guess you do. I dont see how it is a waste of battery due to the fact that the car recharges the battery. I guess we just see things differently.

 

What is your approximate location?

When it gets cold enough outside, fog on the inside of the windows will turn into ice, regardless of who made the car. So if you have seen fogged windows inside in the past, but not ice, then that just means it didn't get cold enough to freeze then, but it did this time.

Under clear night skies, the shallow angle of the Prius windshield may induce it to freeze faster than the steeper angles of old fashioned cars. But again, this really has nothing to do with it being a Toyota, and plenty to do with local climate and the driver's management of interior moisture (though sometimes assisted by more intelligent climate control design in some cars).

 

It's been below 32F in Connecticut this week and I've had considerable moisture on the inside of the windshield twice. Some water remained on the driver's floor mat from wet shoes when I parked the car one morning. Most of the windshield was fogged and the interior was humid when I returned after work. Had to run the engine, fan and front defroster for several minutes before I could begin to drive. Happened again the next day - not as much but there was light frost due to the cold temperature. I use the front defroster to clear the windshield during engine warmup then turn it off - not recirculating cabin air. After a few minutes, windshield begins to fog and I have to turn it on again. Seems to me like the car is prone to moisture on the windshield. If there is moisture in the car, say on the floormats, it might be best to leave the vents open so that it dries out. I'm going to try that.

 

I have experienced this many times over the years with several different cars when I lived in Montreal. It is not frequent but not rare either. It depends on the air humidity in and out of the car as well as the temp variance between the inside and outside of the car. Just warm up the C like any other car using the AC with fresh air intake. It should clear up fast enough.

 

All the air vents on my Gen II and my PiP close when the car is powered down so there is no air circulation through the car to dry it out whilst parked.

I cleaned the upholstery once with too much water and the car was streaming in side the next day. May I suggest you drop the glovebox and remove the air filter cover. This allows air to circulate through the car whilst parked when there is air movement outside (there are flap covered vents hidden in the rear to let the wet air out) this solved my problem in a few hours and might be your answer.

 

That's an interesting suggestion. Cabin filters are a relatively recent concept: go back a decade or so, and the only filter was for engine air intake.

AC use in particular causes water droplets to accumulate in the system. I've found it takes hours, or overnight, for it to evaporate off. If the system's more open to air flow it's got to help.

 

I did not explain properly. The air distribution shutters are downstream of the filter and they close when the power is off.

But removing the filter cover (no need to remove the filter) allows the wind to just blow into the car from where the cover was and exit from the back of the car. Unfortunately the flaps on the exit louvres stop the wind from blowing the other way.

When you drive, or the car has dried out, simply replace the cover.

 

It is normal.
1. ice adheres to areas where the surface is not clean glass simply because it hass something to hold onto. I've heard that using glass cleaner or RainX will prevent this but never tried..
2. frost on the inside just means there was moisture ajacent to the inside of the windshield. Probably got there via the defroster vent. The inside of the glass is as cold as the outsde so sure water will freeze when contacting 17F surface.

 

When it got down to -10 F outside a few weeks back, there was ice inside all the windows of my car and it **stayed there** for a road trip...I waited for it to clear off the windshield at least before I got going.
Same happened with other model cars, day, night, didn't matter.
Just use the defroster, it blasts warm air (once the engine warms up) to the windshield.
Ice on the inner side of an extremely cold windshield sounds normal to me in the dead-cold of winter.
I'm not aware of "fog-proof" windows in the hybrids.

 

Alright so now that I've asked that, this may be sort of an obvious question but it's been near 0F for a week straight and my defroster's behavior has changed a bit. When I'm on the road at, say, 25 mph, my RPM would be say 1400, but when I have the defroster button on, my RPM goes up to 1880 and my fuel economy drops by 25%.

I know that using the defroster takes more energy but normally the RPMs wouldn't jump this much.

Also when I start the car in the morning, the RPMs jump to 1900 sometimes.

I'm not sure how "normal" this is since I had previously done cold starts--or if these two "problems" are related.

Advice?