I have forgotten what a frosted window is, let alone how to defrost it. We Texans stay home both days in a year when it might be a problem.
Anyway, I think there is a button on my dash that decides for me.
If you use hot air, then the frost will melt more quickly, clearing the windscreen in less time. On the other hand, if you use cold air, it.... won't. I am really not seeing the basis for a dispute here.
In fact, I think it's possible that blowing cold air over a frost-covered windscreen might make it defrost more slowly than if you just left it alone.
Defrost or defog? That is, are you talking about condensation or actual frozen water?
3: Yeah, whoops. I meant "defog". Post updating now...
In either case, hot air would work faster than cold air if blown at the same speed.
Also, is it on the inside or outside?
For defogging, hot air plus open windows.
Just to be on the safe side and use all your tools, turn the AC on, and set it to hot.
And then drop a nuclear bomb on it.
Actually it presumably primarily depends on the outside temperature.
7 gets it exactly right. A chamois leather doesn't hurt either.
We had plenty of window-fogging growing up in central Texas. I remember deciding that cold air (opening the windows) was more preventive, whereas hot air was better at treatment. But I haven't driven in years.
Hot air. The warmer the air, the more moisture it can hold without condensation forming.
11: that's why you combine the two; the hot, dehumidified air from the vents picks up the condensation, and the open windows equalize... things.
This comment is bad physics.
11 has a point. Your window fogs up when the window glass is colder than the warm air inside the car. You can either equalize the temperature inside and outside the car, or you can blow hot air on the glass so it's as warm as the air inside the car. But if you don't want to sit in a cold car, then you need hot air.
Doesn't this vary on the car? I found out the hard way that the only way to defog my car's windshield is having the a/c running, even if the air coming out is hot. I have no idea why this would be so, but it really is the only solution that works besides rolling all the windows down (which is impractical, as the only time the windows fog is during precipitation and who wants to be driving at 65 with rain in your face?).
Huh, I never thought of it like in 14. While we did often combine the two, I always felt that method didn't live up to our expectations of it.
In our old Chevette, we had no functional heater. It takes a very long time to defog a windshield using only open windows.
Both will work. Hot will work faster, but be less pleasant. Cold air will take longer but if it's foggy you probably want the ac on anyway, so sit there a while and let it work.
For frost, reverse everything.
Empirically, when my car windows fog up in winter turning on the A/C with cold air is the fastest way to defog them, even though it's unpleasant to make the car colder. As LB says, it seems like hot air should work too, but in practice it doesn't seem to work very well in my car. (Maybe the hot air doesn't get directed to the glass effectively enough?)
Somehow for me this problem seems to arise mostly in winter, not in summer.
Part of it depends on the car. I'm picturing a car (like our old one) that has a little 'defog' setting that blows hot air right on the windshield. If you're just warming up the car air generally by turning the heat on, rather than the windshield specifically by directing hot air on it, you might end up with the windshield remaining colder than the car, and so continuing to collect condensation.
Cold air. The A/C air is dry, and will absorb moisture from the window. If warm air is too moist, it could actually end up depositing condensation on the cold window, although this will cease to be a problem as soon as the window heats up.
20: Same here -- I never notice window-fogging on a hot day.
Also, in my car, hitting the defog button causes the A/C light to come on.
22: You can heat up the air that comes from the AC.
Turn the a/c on, but turn the heat up to high. This gives you hot, dry air. And probably wastes a ton of energy, but at least you can see.
25, 26: Now I'm wondering if I've fundamentally misunderstood the controls of every car I've been in lately (a genuine possibility, I find them puzzling.) Isn't there usually one temperature dial that you can turn from hot, to neutral, to cold, and a variety of fan settings? So if the temperature dial is turned to cold, the AC is on, and to hot the heat is on? I don't get how you'd turn them both on at once.
I keep having to remind myself that some people live in countries where you need air conditioning in your car.
27: There's usually a switch to turn the AC on or off. The temperature dial controls how much heat the air gets from the engine.
LB, the temperature dial just goes from unheated to heated in every car I've ever owned. To actually cool the air via freon, you need to hit the actual AC button.
30: Actually, in actual actuality.
My car has AC but it's never worked in the 18 months I've had it. I presume it needs re-gassed, but I've never gotten round to it. TBH, the normal fan + heat settings works fine except on those rare occasions you get stuck in traffic on hot days.
Also make sure the air isn't on recirc. Though Sifu's open windows approach would make that moot.
I'm beginning to think that LB might not drive all that much.
30: This is weird. Either the 94 Taurus had strange controls, and I've been generalizing from those to other cars without noticing they were different, or I somehow managed to turn the AC on in the Taurus for years without consciously noticing I was hitting a button as well as turning the dial. I really wish the latter wasn't an actual possibility, but it totally is.
34: This is true, I don't, but until the car died last summer, I drove someplace at least once a week for years, and did use the AC or heat depending on the weather.
Gentle mockery aside, there are definitely (luxury) cars where you just set the temperature, and it figures out the mix of systems.
A mid-90's Taurus control panel looks like this. The dial on the right has Max AC, AC, plus a variety of non-AC air directions.
37: Not actually an explanation with potential for applying to a Ford Taurus.
The A/C button pushed in, dial turned to HOT and - contrary to Jimmy Pongo - recirculated air - is the only guaranteed defogger with my ancient Camry. (I know I pretty much already said this, but I feel like repeating myself.)
38: Huh -- that's my dashboard. I think I spent ten years in that car without consciously noticing the letters AC on the right-hand dial -- I had that dial mentally filed under "controls where the fan's blowing" exclusively. I need to save this comment thread for when I'm seventy and afraid of encroaching senility, to remind me that I've always been like this.
If you can remember where you saved the thread. Maybe you should print it out and put it in a photo album.
Tattooing is always a possibility, if I can think of a body part that's still reliably going to be flat enough to be legible at 70.
I suppose the recirc would get it hot faster, but it would also trap the moisture you're respirating inside the car. But of course, do whatever works for your particular beastie.
37 describes my current car -- a 2005 (newest vehicle I've ever owned). It took me quite a while to figure out how the temperature control system works, and to bypass it when it wasn't doing what I wanted it to do.
Its default mode is automatic, and you turn the dial to set your desired temperature, like setting a thermostat. If the outside temperature is colder than that, the heat kicks in; if it's warmer, the A/C does. Sadly, there are times when you don't particularly want the A/C or the heat: say, if it's a mild and pleasant 65 degrees F outside, and you have the windows down. How do I shut this overly sophisticated thing off?? (You turn off the "automatic" mode, and manually manipulate the Vent and Fan buttons. Oh.)
Given the choice between non-AC cold air and warm air, I guess its better to go with the warm air because it will heat up your windshield and increase evaporation. But if the cold air is AC, better to go with that. And warm AC would be the best. So, apparently, its complicated.
I keep having to remind myself that some people live in countries where you need air conditioning in your car.
I have to remind myself that some people live in climates where having the heat on in your car doesn't make you pass out most of the year. I've already started turning on the AC this year on my way home.
I've definitely had my windows fog in the summer, or at least when it was too hot for the heat, but that was the only thing that seemed to work.
My car has state-of-the-art luxury of 1994: separate temperature control for driver and passenger. So when my window fogs up, sometimes I set one side to hot and one side to cold, until I can tell which will work for that day's chemistry.
The worst window fogging I've ever seen was (on multiple occasions) in south Florida with the AC on.
Tattooing is always a possibility, if I can think of a body part that's still reliably going to be flat enough to be legible at 70.
Your butt?
47.last: That happens when your windows are cooler than the environment, so you get fog on the outside and thus need to heat them up.
Lower back, maybe, for a really mystifying tramp-stamp? Considering that it would have to be mirror-imaged so I could read it.
I've been trying to think of a non-cliche place for a substantial tattoo that will still look decent when I am old, and I think I'm going to go for my left side. I think it will hurt tremendously, but I will meditate.
52: Surely, you could have it written normally and find someone to dictate it to you.
I press the AC button and turn on the heat.
This apparently works for a nonintuitive reason:
http://wiki.answers.com/Q/Does_warm_or_cool_air_defrost_car_windows_faster_and_why
Actually, come to think, for the small of my back I'd need two mirrors. So forward works fine.
53: What are you planning on for an image?
53: Between your shoulder blades, or is that too small an area? I didn't find it that painful.
I need to save this comment thread for when I'm seventy and afraid of encroaching senility, to remind me that I've always been like this.
I believe this is what your kids are for.
I've been happy with the one on my ankle. That skin has managed to remain fairly taught.
That skin has managed to remain fairly taught.
No punitive favoring of the skin on other ankle when it comes to quiz questions and so forth.
60: if you lose the foot to gangrene following diabetes-induced circulatory problems, though, you lose the tattoo as well.
Your nose continues to grow as you age and yet retains it's basic shape, making it an ideal location for those with failing eyesight.
This is the image. It's the visual representation of a flourish Corporal Trim makes with his cane in order to remind Captain Toby Shandy that, while one is not yet married, there is freedom, which Toby interprets to mean the peacefulness of celibacy.
Oh shoot. This is the image.
Maybe between the shoulder blades would work, but then I'd never get to look at it.
Remember, AWB: this old chestnut is still available.
Ooooo, that's lovely, AWB. Pretty curves, very tied tied to your identity, supported by a whole lot of thought. Everything I'd hope for in a tattoo.
Considering how pretty it is, if it were on me, I'd want to see it too. Front of thigh? Back of calf?
53: Oh, the pain becomes a pleasant high after a while. Bonus!
Ugh. Reminds me of Mickey Avalon's that ugly tattoo of "THANK YOU" over his cock.
You know, palm of hand might be good. Easy to see for you, fairly discreet, close to your writing, involved in sexytimes...
Yeah, I'd go with calf or thigh. Possibly forearm.
(Also, it really is a pretty image.)
I should also mention that I haven't gotten a tattoo yet because my mother, whose religious ideas are somewhat informed by growing up around voodoo culture, believes that tattoos are the mark of the Beast. So although I will have to come clean about it, I'd rather not put it somewhere where she can stare at it and cry all the time.
Palm of the hand fades really quickly, requiring lots of touchups down the line.
if you lose the foot to gangrene following diabetes-induced circulatory problems, though, you lose the tattoo as well.
I have a large jar of formaldehyde awaiting just this contingency.
When I got a slight scar on my forehead, it took years for her to stop staring at it instead of looking me in the eye. I think the mark of the Beast thing is really just an excuse for her obsession with me looking as physically similar to myself at age 4 as possible.
Oh. I didn't know that about tattoos on the palm of the hand.
LB, my guess is you just unknowingly had the AC turned on in your car all the time for years. The heat will still work. And then your middle temp. control (plus the separate fan speed control) would have been all you'd ever need to touch. Sort of a bitch for your gas mileage, though, I would think.
80: I was certainly moving the right-hand dial all winter, for, e.g., defogging and such. And between around 45 and 75 outside, I tend to drive with the window open and everything else off. So the AC wasn't on for ten years. (It's the sort of thing that I could easily have done, but in practice, I'm fairly sure I didn't.)
I too thought it was standard until recently for A/C to be basically the extreme left on the cold->hot dial.
No one is going to made snide double-entendres about why Stanley's car is so fogged up? don't you guys know the main cause of fogged car windows?--making out! what kind of unfogged comment thread is this?
78, 83: La la la la, I can't hear you.
80 is my guess, too. AC on, heat up, defroster button pushed. My current 2008 GM car has by far the best system I've ever seen; just set the button to defrost and watch it magically go away in an instant while enjoying seat heat. God bless that car.
AWB, that is a lovely tattoo, and I think scrolling down your side it would look great. Go for it and take a photo and post the photo to the flickr page (please).
78: Damn, it looks like my city might just be in the color band that couldn't even be seen in Japan. Guess I'd better mainline iodine.
I can't seem to load that piece in 78. Anyone have an alternate link?
You can't access the New Scientist site?
Well, the summary, basically, is that the levels of the lighter radioactive elements coming out of Fukushima and which have been detected by the apparatus used to monitor the various nuclear test ban treaties are of the same order of magnitude as those coming out of Chernobyl when that happened. Overall levels of toxic/radioactive byproducts, because Chernobyl was producing a lot of shit other than just caesium-137 and iodine-131, but levels of those coming out of Fukushima are broadly similar.
Also, fun fact, Fukushima has 10 times as much fuel on-site as Chernobyl did.*
* much of which is, presumably, safe and in no danger of being dispersed.
re: 91
That should have read 'overall levels of ... are lower because ...'
The article very studiously avoids affirmatively stating that anyone has concluded that anything coming out of Fukushima poses an actual health risk to anyone, though, so I'm going to not worry about it.
The trickier things is when your car fogs up on the inside. I'm itching to try this fog clear stuff
I want to put it on the mirror in my bathroom.
It sounds like it might be bad to be a baby drinking milk from cows living on the pacific ocean off the coast of Japan though.
94: Good move! I read somewhere that the most dangerous thing about radiation is the anxiety caused by worrying about it.
[M]y mother, whose religious ideas are somewhat informed by growing up around voodoo culture, believes that tattoos are the mark of the Beast.
Wow. That is a Dagwood sandwich of syncretic eccentricity.
91: maybe he works at Old Scientist
99: That reminds me of an amusing spoof magazine released one April Fool's Day at my alma mater: Unpopular Science.
Things I've done - wiping down the inside of the windscreen in front of the driver on the M25, basically every trip. Going from a 1984 Peugeot 205 to a 1995 Ford Fiesta was a small revelation, but only in that depressing "oh, it's possible to fix my problems with more money" way.
Anyway, which Lonfogged members are marching, and what are your plans?
There are questions outstanding for you in the NMM thread, Alex.
Thought about marching although did already have plans anwyay. But everything is up in the air at the moment as C's grandfather is dying - C has been at the hospital in South Wales since Wednesday - so not going far from home. (And have cancelled my other plans, which was a tour of the Diamond Light Source and am feeling pretty miserable about that too.)
Anyway, which Lonfogged members are marching, and what are your plans?
I had planned to, but had some pathetic domestic commitment I couldn't get out of. I spent the morning trying to get things done so I could get into town, but no joy. Hope it's going well, though.
These AC/heater/fan approaches only attack the symptoms. Breathe through a respirator hung out the window, and there's no excess moisture in the car to fog up.
106: What if you sweat? Or pee your pants? I think we're going to need more tubes.
Me, I just glow. Always happy for an excuse for more tubes, though.
