Frost on *inside* of Windshield

Tested it tonight. Took the spounge out still mist and put the sponge into my new Prius. No mist. So conclusion? What you said doesn't hold true. Because then it should be my prius that mist up now and not my frends car.

 

I just had some experience drying out a car (not the Prius) flooded by a leak. It took a week with a mixture of drying the floor mats in the house, sponging water out of the carpet, leaving the sunroof open in the middle of the day, and drying the inside windows each morning with a towel not kept in the car. Most nights were sufficiently cold to condense out significant moisture. But it is now dry enough that no frost formed inside on a clear night with the air at 24F (-4C). There was plenty of frost outside.

A single sponge movement for a single day is not likely to have a noticeable impact. Try it multiple days, and look for other stores of moisture, particularly damp carpets and seats.

And make sure that the ventilation system is NOT set to Recirculate.

 

Dude I had my Acural RL since 2005 and never once did it mist inside the car. So I still think the build quality of the car counts a lot regarding this issue. I don't see Lexus people complainng about this issue either.
Personally I havn't had mist in my Prius yet but I hope it doesn't get to that strage or I will be rather upset.

 

We got our first snow last night and voila- this morning, I had the same problem you had. I think my husband drove about 3 blocks before i couldn't stand it anymore and had to wipe it away with my glove. And in 3 blocks0 it only defrosted the very bottom. I came to see if anyone had the same problem . Thanks for posting it.

 

In Seattle's wet climate, 'build quality' alone cannot prevent window condensation. It is a matter of basic physics.

A car's climate control system can be designed to actively manage the moisture issue so the operator doesn't have too. But this is separate from build quality.

 

As of late, I have made a point of automatically hitting the front window defogger button immediately after start-up in the morning. This seems to prevent any fogging from taking a foot-hold and I don't have to battle with a obscured windshield for the first five minutes of driving or so.

As an aside, I don't dry my hair before I leave in the morning, so I'm sure that has something to do with the amount of moisture I deal with inside the vehicle in the morning.

 

The yellow, round, extension cord ends at the driver door.
The black, flat, 2 wire cable from the heater I put outside and close the door over it. I never use exactly the same spot twice, I just have to be careful about where the clip is.

The rubber gasket seal around the door holds the wire in place. It's quite thin, it's like a 14 gage wire.

I'd like to setup something better, but hey, it works. Dry and warm. The heater costs 20$, the extension 10$ and the outdoor timer 10$.

It's saved us from hacking the Prius with a remote starter, to simply have a warmed up car in the winter.

 

I park in a garage, maybe that's why I don't get frost on my windsceen

 

lol show off. Hopefully once I get my engine heater I won't have that problem. The moment into the car I will switch everything to max.

 

Seriously I know you want to win the argument. I don't. I just point out what I see and my EX car never used to Mist Dew or fog inside the glass. But my Friends car does!
Luckily Prius doesn't so far (cross my fingres) If it ever forst inside the car glass then I will seriosly contemplate on changing the car. Since I always felt the Prius especially 3rd gen are made very flimsy. Their whole excuse for making out of cheap material or light material is to save weight. Even the wheel arches on the front or back (can't remember) is made it ouf of cardboard!
I never had or used to have a car that has used that kind of material. Cardboard? Come on how long will Cardboard last? Usually it is has a layer of TAR. Only one set of wheel arches have TAR.

 

Yup, don't use recirc if you can avoid it. Yesterday I had lots of frost on the inside of the rear window after stopping for an hour or so. Nice thing is the rear defroster works faster on frost on the inside than on the outside.

Crispy critters!!!! It's a nice -36C this morning! That's officially COLD in my books! Just about time to "bring in the brass monkey"!

Pearl starts just fine in those temps, but I sit and shiver for quite a while, as she takes a long time to warm up in these temps. The EBH (or block heater in these parts) does -something-, but not a lot. Coolant temps were barely in the + range after leaving it plugged in all night (+10C or so). And Pearl is in an insulated but unheated garage (-15C in there).

Poor car!

 

I do the opposite. For both air quality and moisture control reasons, my climate control is always set for fresh air unless a brief batch of extra-bad outside air is encountered, or the car is warming from a very cold start. I live along the I-5 corridor, which has essentially the same climate as your I-405 location.

Unless a car is sealed with a source of clean air, I don't see how the inside air can be cleaner than the average outside air. Like most buildings, it is normally worse. As a kid living along a gravel road, when parents had the car's ventilation turned off, I often watched thick dust pour in through gaps in the door gaskets. The interior had a slight negative pressure, from air being sucked out through gaps at window level. This drew in dust and exhaust from our own car, through other gaps below. Cars of that era emitted considerable CO. I recall the newspaper reporting back seat CO poisoning deaths, usually sleeping children, nearly every year until the late 1980s. This probably was a cause of my own frequent childhood car sickness.

Because I keep cars a long time, some gaskets will deteriorate and cause gaps.

The fresh air intake is ahead of the engine and wheels, so it 'breaths' only the very diluted dust and exhaust from vehicles ahead, not the concentrated stuff generated under your own car. If the fan is turned on to create a slight positive pressure, then dust and exhaust don't get sucked in through the gaps and holes. Instead, interior air flows out those openings.

Normal human respiration emits considerable moisture, from both lungs and skin. If the car is sealed, interior humidity rises. When warm humid air hits a surface colder than its dew point, it must condense. It doesn't matter if this cold surface is auto glass, a home window frame, the inside of a GoreTex rain shell, or a sleeping bag cover, it gets wet. The best solution is to push the moisture outside.

I'm a bit surprised that you get enough benefit by just leaving the recirculation off when parked overnight. This suggests that your initial humidity was only barely over the dew point, so not much water had to be let out. I often have multiple people getting into the car, after hours of soaking-wet hiking or skiing. This brings in huge amounts of water, which takes several days of active ventilation to fully clear.

As for other cars that never fog inside, it is possible to make a climate control system to handle this automatically. But none of my cars (before Prius, the most recent was bought 13 years ago) has had such a feature.

 

Hello all inside frost people. I'm a Gen II (2005) owner and have read and tried all the solutions on both boards to no avail. One exception is I have not tried an anti-frost spray inside. Not sure those chemicals are a good idea inside.It does not fog or frost up inside in my garage. Both happen while parked in a lot at work. I'm in Stuttgart, Germany. Sometimes it will frost only on the inside. It is not a frost that will dissipate by defrost alone. I had to scrape inside again. I'm inclined to believe it is just a design flaw. Hey maybe we can get them re-called. I've been driving Toyotas for 40 years in Ohio (Coronas, Celica and now Prius, and did not have this problem before. BTW, I put over 220K on the Celica. There are just too many people who post on here for this to be a simple "operator error" solution.

 

I used to have this problem but I figured out that you should *NEVER* run the defroster using recirculated air. Since then I've never had the issue again.

 

I'm another Seattle area member who's had ice inside of every car and truck I've owned. It seems like the more it sits outside, the more dampness it has. It's particularly bad if it sits for a few days and the sun comes out along with freezing temps. I think its a kin to having a cold beer can sweat on a hot day, except it's the other way around.
I also figured out early on that with the dampness we have, I can't use recirc to defrost.
I'm curious though, on most cars the AC kicks in when defrost is activated but I have not noticed that on my car. Does the prius do that too?

 

Yes, the Prius will run the A/C to dehumidify, unless the A/C compressor is disabled or it is too cold. It's harder to tell when the A/C is in use with the Prius. The Prius A/C compressor is a variable speed direct drive electrically powered unit, so it will run as needed and only as much as needed.

Tom

 

Thanks Tom, that explains why I can't feel it "clunk" on like normal cars AC do.