Condensation in car - cat litter fix..?

born_again

Do you get inside your car hot while driving & then not vent that hot air out before parking up?
Do you have A/C in your car & not use it? A/C dries air out...

facade

Pingi work but are fabulously expensive.(Pingu is the little animated penguin that they are not cashing in on the fame of by printing colour changing penguins on the bags) 

They are just silica gel in a nice bag with a penguin on it. (don't over microwave them hoping to get the moisture down below 25g, they develop a hot spot and the bag melts- guess how I know)

The crystal cat litter is silica gel, and works just the same, but you have to dry it out before use as the packing isn't moisture proof. (You can bake it in a low oven in a dish, or figure out some way to get it in an air fryer, an old Actifry would be ideal, if it was completely degreased first)

Lidl sell cheap dehumidifer bags when they sell car stuff, these contain finely powdered clay, (probably the other sort of cat litter) which do work, but I find that they stay permanently puffed up when they are microwaved to dry them, and they leave fine brown dust behind on the dash top.

I've spent a fortune over the years acquiring bagged silica gel, and on forcibly drying it out, but it is a tiny fraction of the cost/trouble/health risk of letting damp get a hold on the upholstery/seatbelts/carpets!

I write the dry weight on the bags in sharpie the instant that I unpack them, and then I weigh them, and microwave when they are above 20% overweight  (a 485g one weighs more than 600g)  

They will eventually increase in mass by 40% but the adsorption slows down a lot after 20%.

Get 500g bags, anything smaller is a waste of time, they are 4 for about £18 on eBay, which is expensive compared to a bag of cat litter and a couple of ice cream tubs, or half an hour with the sewing machine and some old T shirts, but a lot less trouble!

I don't know why it is called silica gel as it is a hard solid, but I'm not a Chemist!

The brown clay is bentonite.

For the pedants, they both work by adsorption of water vapour into the micro pores on their surface. 

Bigwheels1111

Well today was the first very cold day, I forgot to put on my screen cover.

So screen was solid ice at 05.00AM.

A few squirts of Prestone de Icer and it melted away.

But, now water dripping down the screen.

So much better, With the 4 bags and 2 pots.

facade

It takes a few days for the silica gel to dry the inside of the car out.

The condensation on the inside of the windscreen is the tip of the iceberg

GDB2222

I’m betting that there’s a leak somewhere. 

twopenny

Every time you get in the car with wet shoes and coat you're making the mats wet.
When I worked I used to take the mats indoors and dry them. That sorted a lot out.

Now I swim a lot and the windows huff up so o drop them a tad with the heating on while driving. That sorts a lot out.

Icy mornings are a bind but I found tap hot, not boiling poured on the screen also stopped condensation inside.

I did have to resort to desiccant tubs but they didn't really help with the fugging up which is me huffing hot air towards cold glass.

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twopenny said:

 <snip>

I did have to resort to desiccant tubs but they didn't really help with the fugging up which is me huffing hot air towards cold glass.

Fugging up when going along is a separate issue, one cause is leaving the air con on auto climate.

To keep the windows clear you need to override the climate control and force air through the dash vents all the time.

Left to it's own devices the car just stops the air when the inside gets to the set point, unless you have a super posh one that actually controls the humidity as well- I think some BMWs will continue to circulate the cabin air through the chiller to dehumidify it- I don't know if they keep blowing dry air on the glass or just stir it round your feet.

My Citroen chills the cabin air to dehumidify them warms it up again, but it still fugs up in cold weather because it doesn't bother to keep blowing warm air on the glass so it cools down below the dewpoint, and I can only hold my breath for a few seconds.

I have to set the air vents to windscreen and keep the fans on manual, otherwise every time that I can't see I have to use the windscreen defrost button, which is very loud.