Effective ways to reduce humidity inside the car

Messages
595
Location
Southern NY
Thread starter
2006 Sentra, blown AC unit. Do not intend to fix it due to the costs involved. Its been sub-zero for the last 2 days. Today morning, got into the car to drop the kid off to the school and noticed that both the windshield are frozen INSIDE. This happened for the first time so took me a moment to register. Sprayed the deicer and cleaned the windows. The windows fog all the time during rain or cold days (until the car warms up). I wonder what options do I have to keep the humidity low inside the car, other than leaving the windows cracked open. Googlefu tells me that I could use kitty litter gel crystals in a sock. I have never used these (no pets). Are these any different than the silica in silica packets? I ask because I would like to know if they will make a mess after absorbing moisture. Then I would leave such sock in some kind of flat container. Any other ideas? Thanks in advance.
 
Messages
16,712
Location
NH
Seen that before, not in a while though. In winter time I used to drive with a window cracked, until the engine warmed up and I had some heat. Still do on occasion, as I don't let it warm up before driving off. That won't work in summer when it's raining; might be out of luck there, short of running heat on a warm day. If you don't want to crack the window, maybe a remote starter? Or an engine block heater. I'm not sure of a better way. Humidity is going to get in and I know I would not want to be constantly carting kitty litter around.
 
Messages
15,091
Location
Upper Midwest
Yes, effective defrosting is almost a more important benefit from an A/C unit than cooling in the summer. The gel packs will do nothing for your needs. There is so much makeup air in the car and the gel will be so slow to remove moisture it will be useless. The only things you can do is either get the A/C fixed or add heat to the defrost air. When the coolant is cold there is nothing you can do that will help until the car warms up.
 
Messages
56
Location
WI
Back in the day you could find moisture absorbing packs that contain some beads. (Like these: https://www.amazon.com/Dri-Moisture-Absorber-Storage-pouches/dp/B00Q3H1K0S) I used a couple in an old '88 Jetta that constantly leaked water in through the passenger side dash/vent area. Little did I know at the time that my drain vents were somewhat clogged. Every time after the car sat in the rain I'd find a puddle on the floor that would slosh around for awhile. Those were the days... 17 years old and free to go anywhere! I'd revisit that A/C fix. Parts should be cheap, you could DIY it. Good luck
 

Kestas

Staff member
Messages
13,791
Location
The Motor City
One step to reduce humidity is to keep the floors dry in the car. Kick the snow off your shoes and use rubber floor mats where you can dump the water out. Other than that I manage cabin humidity in the winter by warming up the car for good defrost or rolling the windows down in tight situations. Outside air has a very low dew point in the winter. Yes, there have been a handful of times where I needed to scrape the inside of my windows.
 
Messages
856
Location
Under the Hood
If you park in a garage, open the window two inches after driving. Winter air is very dry and will evaporate any water. I've been doing that for years and it's very effective. If you park outside, how about leaving a sponge on the floor so it soaks up any water / when done driving, wring out the sponge.
 
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9,373
Location
Canuck living in California
I believe when the topic came up in the past someone said they left a small space heater inside the cabin and put it on a timer. They claimed it worked great. I don't see why it wouldn't, but it is also a potential fire hazard.
 
Messages
11,364
Location
Illinois
I did that. Don't know about humidity control as my A/C worked. But it does encourage one to keep their car clean. I'd have the timer kick on a couple of hours before I planned to leave the next day. I used high capacity extension cords, as short as I could get away with. If I was on-call, I'd have it run for an hour and then off for an hour all night long.
Originally Posted by KrisZ
I believe when the topic came up in the past someone said they left a small space heater inside the cabin and put it on a timer. They claimed it worked great. I don't see why it wouldn't, but it is also a potential fire hazard.
 
Messages
421
Location
Seattle, WA
I use a dehumidifier in my cars once a month or so to pull all the excess moisture out. If you don't want to buy a new one, there are always some on CL or offerUp that can be had for fairly cheap. They only work to about 45 degrees, so if it's cold overnight, I would run it right after you get home so that the car is warm enough to actually pull the moisture out of the air. I've also done the portable heater and fan combined with the dehumidifier, but that was a bit cumbersome and likely a fire hazard. Ultimately, you likely have a leak that is causing water to pool under the carpet. Check your sunroof (if you have one), the heater/condenser drain is clean, and make sure the cowl area under the wipers is free of leaves/dirt. Reach under the carpet in the drivers and passenger side front foot-well and touch the underside to make sure it's not soaking wet. Carpet has a vapor barrier on it, so it could be totally dry on top but moist underneath, causing the fogging.
 
Messages
6,856
Location
California
Originally Posted by gathermewool
Fix your A/C Why is your car not worth fixing the A/C?
System probably requires a total replacement. When a compressor gives out, metal shrapnel mixed with the Teflon or moly coatings on the compressor's parts creates black death. I'm not a fan nor advocate "fix-in-a-can" like AC Pro since it can and will contaminate R&R machines used to service AC systems. But if the car's last stop is a junkyard it might be a thing to try.
 
Messages
4,112
Location
WA
Originally Posted by CR94
Stop exhaling inside the car.
Only one thing I know of that could involve that much exhaling of humid air typically involves the back seat and the office secretary...js ...€ Edit: do those 12v heaters work? Never had one myself so dunno.. probably not, they seem small.
 
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Messages
1,186
Location
California
Keep out water, ice and general moisture as much as possible. Keep some towels in the car and rotate them out when they get damp or wet. Heat will melt the ice but can also fog the windows really bad.
 
Messages
15,091
Location
Upper Midwest
Originally Posted by DGXR
Heat will melt the ice but can also fog the windows really bad.
It shouldn't if the dew point of the warm air is above the temperature of the glass (which isn't hard to do in the winter).
 
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