Moisture on inside of front windscreen

[soulstyledevon]

I had a this last year. I first got loads of heat through the van by keeping the diesel heater on and the windows slightly a jar.
Then bought one of those moisture catchers from Halfords, which actually works.
Finally read an article suggesting Aircon should be used all the time through winter. I never used to use AC over the winter months.
Anyway, this winter I have had no condensation problems. So something has done the trick.

 

[Teejay]

I had a this last year. I first got loads of heat through the van by keeping the diesel heater on and the windows slightly a jar.
Then bought one of those moisture catchers from Halfords, which actually works.
Finally read an article suggesting Aircon should be used all the time through winter. I never used to use AC over the winter months.
Anyway, this winter I have had no condensation problems. So something has done the trick.

I use the Air Con all the time, as I understand it, the seals dry out if you don't use it for long periods of time and is costly to fix.

...me...

 

[MattBW]

The tip above about closing vents when parked has made a big difference to me, give it a go Combined with the rechargeable dehumidifiers I dont get much issue now.

 

[Cwoods1405]

Glad it worked for you too!

 

[Jabberwocky]

This moisture thing seems to be quite an issue - it got me thinking! There must be some science that can help us understand this matter.
When people are asleep they loose moisture to the atmosphere, increasing the relative humidity, by breathing and to the bed mattress / bed clothes by sweating. This loss of moisture can be anywhere between one and one and a half litres per person. So if you are two (I guess that will be most of us), that is up to three litres per night. That is quite a lot of moisture in a small Cali airspace. A rough calculation is about 9.5 cubic metres air space. How much water can that amount of air hold?

So as you can see the majority of the 2-3 litres of water will condense (the air in the Cali will only hold approx 100g at bedroom temperature leaving 1.9-2.9 litres to condense).
This condensation will be on any service that is colder than the air temperature - including the fabric of the van.

You get condensation when warm air that is 100% moisture laden comes into contact with a colder surface. This condensation takes place at what is called the dew point.

So ventilation, ventilation, ventilation is key both during the night and at other times when you are using your Cali for sleepovers/holidays etc. Don't be fooled when the windscreen is clear of condensation that the rest of your pride and joy is also condensation free - it will not be. @Teejay1 you are on the absolute right track - use your A/C when ever you can. Oh, and always air your bedding/mattress when ever you can - there's a lot of moisture in there!!
I hope the above helps everyone understand the nature and size of this issue. JW

 

[T6 CFO]

Thanks. Glad I got the air safe and wind deflectors. Back open, windows open and heater on for me.


Mike

 

[WelshGas]

This moisture thing seems to be quite an issue - it got me thinking! There must be some science that can help us understand this matter.
When people are asleep they loose moisture to the atmosphere, increasing the relative humidity, by breathing and to the bed mattress / bed clothes by sweating. This loss of moisture can be anywhere between one and one and a half litres per person. So if you are two (I guess that will be most of us), that is up to three litres per night. That is quite a lot of moisture in a small Cali airspace. A rough calculation is about 9.5 cubic metres air space. How much water can that amount of air hold?
View attachment 18896
So as you can see the majority of the 2-3 litres of water will condense (the air in the Cali will only hold approx 100g at bedroom temperature leaving 1.9-2.9 litres to condense).
This condensation will be on any service that is colder than the air temperature - including the fabric of the van.

You get condensation when warm air that is 100% moisture laden comes into contact with a colder surface. This condensation takes place at what is called the dew point.

So ventilation, ventilation, ventilation is key both during the night and at other times when you are using your Cali for sleepovers/holidays etc. Don't be fooled when the windscreen is clear of condensation that the rest of your pride and joy is also condensation free - it will not be. @Teejay1 you are on the absolute right track - use your A/C when ever you can. Oh, and always air your bedding/mattress when ever you can - there's a lot of moisture in there!!
I hope the above helps everyone understand the nature and size of this issue. JW

And you only based your calculations on sleeping passengers for approx 8hrs out of 24. When travelling or sitting in the vehicle outside these hours the same thing is happening.
Ventilation is the most important think to decrease condensation.

In fact the more double glazing there is then the more likely the condensation may develope on other surfaces other than the windscreen.
I ventilate a lot and have 2 x Disposable humidifiers which between them remove at least 1000mls of water every 6-8 weeks, especially during winter.

 

[Andy]

My condensation occurs during the day without use in carpal at work. I accept condensation when sleeping in it if no ventilation.

Sent from my SM-G900F using Tapatalk

 

[Jabberwocky]

And you only based your calculations on sleeping passengers for approx 8hrs out of 24. When travelling or sitting in the vehicle outside these hours the same thing is happening.
Ventilation is the most important think to decrease condensation.

In fact the more double glazing there is then the more likely the condensation may develope on other surfaces other than the windscreen.
I ventilate a lot and have 2 x Disposable humidifiers which between them remove at least 1000mls of water every 6-8 weeks, especially during winter.

I concentrated on sleeping time because in my investigation I discovered that we all loose about half of that during the day and with normal use air circulation is much easier to deal with as a result of much greater air movement. But as you, I and one other said VENTILATION - this should include a/c use if fitted, particularly if raining and general humidity is high.

(Edit: Sorry, make more sense now!!)

 

[Jabberwocky]

My condensation occurs during the day without use in carpal at work. I accept condensation when sleeping in it if no ventilation.

Sent from my SM-G900F using Tapatalk

My condensation occurs during the day without use in carpal at work. I accept condensation when sleeping in it if no ventilation.

Sent from my SM-G900F using Tapatalk

Have you had the Cali since new? Or only started happening recently?

 

[jts46]

Never ever had this problem, we do use a silverscreen (outside), always sleep up top and always have window blinds unzipped.

 

[Jabberwocky]

Never ever had this problem, we do use a silverscreen (outside), always sleep up top and always have window blinds unzipped.

I'm sure your habits help. The canvas of the roof breaths and your have the window blinds unzipped - lots of ventilation - excellent!

 

[jts46]

I'm sure your habits help. The canvas of the roof breaths and your have the window blinds unzipped - lots of ventilation - excellent!

Also the bellows are proper canvas

 

[Cwoods1405]

When I'm in it condensation is not an issue. It's when it's on the drive! Sunny day followed by cold night the worst!

 

[WelshGas]

When I'm in it condensation is not an issue. It's when it's on the drive! Sunny day followed by cold night the worst!

Humid air inside. I would suggest trying some Disposable DeHumidifiers - B&Q or eBay

 

[Andy]

Humid air inside. I would suggest trying some Disposable DeHumidifiers - B&Q or eBay

I had a 240v dehumidifier in my van for at least a week, pulled a lot of water out. Two days later got condensation on inside of windscreen = made no difference.

Sent from my SM-G900F using Tapatalk

 

[WelshGas]

I had a 240v dehumidifier in my van for at least a week, pulled a lot of water out. Two days later got condensation on inside of windscreen = made no difference.

Sent from my SM-G900F using Tapatalk

Well the cause is still humid air inside condensing on a cold surface, so either you need to run the Dehumidifier for longer or you have a leak and some trapped water. Have you checked under the carpets in the footwells and between the front seats?
Did you run the Dehumidifier until it stopped collecting water?
Did it rain at all during the period running the Dehumidifier?

 

[Jabberwocky]

When I'm in it condensation is not an issue. It's when it's on the drive! Sunny day followed by cold night the worst!

I think that's easy to explain. The air in the Cali warms up with the sun increasing evaporation of more moisture (already in the van) and when it starts to cool down as the sun's power reduces the water vapour in the air condenses on the outer cooler surfaces. This will continue until the Cali is fully dried out or the source of the moisture is found and eliminated.

 

[The Merle]

Hi Andy

Maybe you gave the same problem as me, vw found drivers door seal had gone and water was getting in. They believe this was causing moisture/frost on the inside of windscreen, fingers crossed its fixed. Will have to wait for another cold snap.
This problem was only happening when van was being used as a daily drive andair con was always used.
Will update once the freeze comes again.
Thanks for everyone's help

 

[Andy]

Well the cause is still humid air inside condensing on a cold surface, so either you need to run the Dehumidifier for longer or you have a leak and some trapped water. Have you checked under the carpets in the footwells and between the front seats?
Did you run the Dehumidifier until it stopped collecting water?
Did it rain at all during the period running the Dehumidifier?

Yes the carpets were up. Don't remember if run till no more water collected. Don't remember if it rained whilst doing it.

Sent from my SM-G900F using Tapatalk

 

[Blubus]

This morning my Ocean was frozen in the inside of the front screen. I use the AC all the time and drive it everyday. Yesterday the sun was out at the temperature dropped overnight so condensation formed. I don't believe there is a leak just warm air condensing on a large piece of glass.

 

[WelshGas]

Disposable Dehumidifiers would help by drying the air inside on the warm days.

 

[The Merle]

Update

Finally woke up to a thick frost this morning, the good news it was only on the outside of the windscreen!
So fingers crossed breeze in totton have resolved the problem, which was the drivers door seal leaking.
I even had a very wet and smelly woof in van yesterday

 

[soulstyledevon]

Woke up yesterday and today to the inside of the van screen frozen.
I’ve decided to give the van a good drying out...

 

[Hotel California]

Woke up yesterday and today to the inside of the van screen frozen.
I’ve decided to give the van a good drying out...

View attachment 54342

When sleeping in cali we put on the aircon when leaving in the morning (when driving off) it takes away the moist air ....