# Help - Condensation



## 96090 (Aug 22, 2005)

Could do with sharing this, and getting your thoughts.

We were away at the weekend in our 08 Autotrail 700SE for the first time.

We've had 2 motorhomes previously and used them year round without experiencing this though.

We were only away for Saturday just to check everything, as we've only had the van for just over a week.

However, on waking on Sunday morning, we discovered that the quilt cover that the kids had used in the overcab was wet and that the roof had lots of condensation in this area - so much that it had in fact dripped.

I don't believe this is rain water as we've had plenty of that since we got the van and everything in that area has been perfectly dry until we actually spent the night in there.

We've never experienced this with either of our previous vans and we did use them in far more extreme cold/wet conditions.

We were on an EHU and had run the electric side of the truma with the blown air unit on all night, but on setting 6 or so of the heating and 3 or 4 on the fan.

Never used the gas at all.

Please convince me this is condensation!

And if it is, how do I solve this problem until we find someone to install aircon in Scotland.

TIA

Scott


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## johng1974 (Jan 17, 2007)

hi Scott.. cant really help but maybe buy/borrow a dehumidifier?

maybe the atmosphere is damp and that part of the van is showing it?

John


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## UncleNorm (May 1, 2005)

Hi Scotty! Stop panicking! :roll: 

Condensation results from either warm air meeting cold surface or cold air meeting warm surface. It's not helped by the fact that we exhale warm water vapour as we sleep.

During the day, the warm air, full of moisture, has been rising into the luton area, keeping it warm, keeping the walls and ceiling area warm, so no condensation.

During the night, as the temperature subsides, the moisture content cools too against the cooling walls and ceiling area. Of course, there's extra moisture from the kiddies sleeping up there. There's some scientific explanation for all of this, but it is a fact that the cooling moisture will wet all the cool surfaces to such an extent that it will start to flow.

Now, I'll give a secret away here... I could never work out why I used to SWEAT in the winter while in bed. It was awful, the pillow would become saturated!!  But it seemed I only sweated OUTSIDE the blankets, not under them where it was very warm. I spent years trying to work the problem out! Then it occurred to me...

The dampness on my head and shoulders at night-time was not in fact sweat but CONDENSATION!! My warm body was causing the moisture in the cool air to condense ON ME! 

Solution... either I become equally as cold as the surrounding air by sleeping naked out of the blankets - not a pretty sight - OR I warm up the air that surrounds me. 

This last New Year, temperatures below zero, we left an oil-filled heater plugged into an electronic plug-in thermostat (Google ET05) and set at 15 degrees C. This kept the air in the MH warmer, I slept like a log and woke to a dry pillow!!

Your luton has to be kept warm. There has been a recent thread about this. Someone even suggested an electric blanket! Hey, why not? 
Someone suggested leaving rooflights open a little to allow some of the moisture content to escape from the MH.

One thing for certain, I can now understand why folk, especially men, wore hats, or nightcaps, in bed all those years ago! :wink: :lol:


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## MaxandPaddy (Mar 18, 2006)

Hi Scottch,
We use our Motorhome all year round in the UK and have had condensation so we bought a dehumidifier and that has solved the problem.
It is amazing how much water has accumalated over night!
In winter when it is too cold to leave your roof lights ajar to provide ventilation I am sure you will find a dehumidifier will cure the problem.
If it is very cold we also run a small oil filled heater on too,of course you need to be on EHU to run the above but I am sure you will notice a difference if you try the above.
Happy Motorhoming!
Val


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## Rapide561 (Oct 1, 2005)

*Condensation*

Hi

I rarely get an condensation in the van, and if/when I do, it is a tiny amount on the windows.

I sleep with two windows on the night catch though to allow a bit of air movement.

Does the Luton area have it's own blown air heating outlet?

Condensation forms when warm air lands on a a cold surface. Was the roof of the Luton all wet and full of condensation or just a small corner?

I think you need to leave the heating on in the van overnight, but with no people inside. In the morning, nip out and check. If there is no condensation there, then this suggests that the warm moist air that you are breathing out may be forming condensation. Next time you use the van with people in it, leave two or three windows on the night vent.

Russell


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## 96090 (Aug 22, 2005)

Thanks for all these extremely helpful replies, they're very very much appreciated.

To clarify, we had left the heating on all night, albeit at a lower setting that we had on in the evening.

Sadly, there isn't a heater outlet in the luton - again, this is a first for us, both previous vans had this feature.

Since all the heater outlets are low, what would be your thoughts about leaving the truma fan unit off, thus allowing the heat from the fire ti rise directly to roof level and hopefully redistribute itself to the luton as it is the highest part of the roofline.

I have a large domestic aircon/dehumdifier unit that I could stick in the van tonight. It has it's own condensation reservoir, I suppose I could leave it on for 24hrs and see how much moisture it draws from the air?

Again, thanks for the replies - I was beginning to get a bit panicky!


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## AberdeenAngus (Jul 26, 2008)

If it happens and it hasn't been raining, then its not rain.

Unclenorm
"My warm body was causing the moisture in the cool air to condense ON ME!"

I too suffer from sweating a lot at night. Believe me, it is sweat, not condensation.

Condensation forms on cold surfaces not warm.
In order for condensation to form on your skin, it would need to be cooler than the surrounding air !


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## maddie (Jan 4, 2006)

Hi hope this helps :lol: firstly you must eliminate all sources of moisture / steam etc, this means cooking, drying clothes/towels,showers etc. :lol: I don,t mean by not doing it but by opening windows/vents whilst doing any of the above.
Each person in the van breaths out about 1,1/2 to 2 pints of water per night (ladies the best time to get weighed is first thing in the morning after breathing out all this fluid :lol: ) so the more people the more moisture.To eliminate this you can either dry it out by turning heat up or vent it by cracking open a window or 2.The best thing is if sleeping in the front open the rear window or roof vent and if in the rear open the front cab windows a bit thus staying out of any drafts :lol: As to the poor kiddies in the Luton it is a case of blowing in more heat (fan heater?)or fitting a roof vent (not nice to sleep under if really cold)other than that the thing no one has mentioned is it needs more insulation 8O Since the makers did not do such a good job of insulating it in the first place. :lol: The hot air moisture will always rise to the highest point which in your case is the Luton hence the need to vent or insulate :wink: 
tery


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## pgjohnso (Jan 8, 2009)

*Condensation*

We have an 07 Sundance 590RS and we suffered a similar condensation problem last year. Condensation within the luton "void" was dripping through the speakers in the roof. After several inspections, the vehicle was returned to the Swift Factory to have the "pillars" on each side of the luton (behind the Cab) filled with insulation and "capped" on the top.
This winter we have had no re-occurance of that particular problem. 
We have experienced heavy condensation on the Cab windsreens and side windows but I believe fitting an external "silver" window cover can help rectify this.

Peter Graham-Johnson


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## sallytrafic (Jan 17, 2006)

Over the range of temperatures in your van the hotter the air the more moisture it will be able to carry. So when occupied heat alone will not solve condensation problems, the key and easiest option is always ventilation. 

Obviously the better insulated the van the less likely there will be suitable condensation surfaces. The other way of removing moisture is with a dehumidifier. I have a small Peltier effect one from B&Q around £30 it draws 20W and literally freezes the moisture from the air.


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## Rapide561 (Oct 1, 2005)

*Condensation*

Just a thought - could the Luton not be adequately insulated?


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## 96090 (Aug 22, 2005)

Autotrail say the 700SE has a class 2 rating for insulating properties.

It was a clear sky when we went to bed on Saturday night, so probably below freezing outside.

IIRC the class 2 rating is based on the vans ability to maintain 20'c in 0'c conditions over a set time scale?


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## Andysam (May 10, 2005)

I thought Class III was sub zero so that may be correct.


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## maddie (Jan 4, 2006)

scottch said:


> Autotrail say the 700SE has a class 2 rating for insulating properties.
> 
> It was a clear sky when we went to bed on Saturday night, so probably below freezing outside.
> 
> IIRC the class 2 rating is based on the vans ability to maintain 20'c in 0'c conditions over a set time scale?


If the van was at say 20c then that would not be hot enough to make the air dry-probably only make things worse,eg hot air, cold van side = condensation -- to dry it out with heat would make it uncomfortably hot,hence the vent bit :lol: 
terry


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## pneumatician (May 1, 2005)

*Condensation*

Our friend with an Autosleeper had this problem where his wife complained that the water was running down her back upon start up in the morning.
Autosleeper found it was definately condensation caused by an insulation gap in the overcab area.(missing polished irene).
If you put a dehumidifier in whilst you are in the van you will be surprised how much water it removes. We have one in the house, removes about 2 pints a day. Do not completeley seal the van !! 
Figures are available for how much we exhale during the night. Also ask someone who has slept in a modern Nylon Tent or Tunnel.

Steve


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## teensvan (May 9, 2005)

Hi.

We had a problem like yours but it was all in the overhead lockers and in the garage area. We lined out all the lockers and garage area with thin hessin backed carpet that you can get from most carpet stores. It can all be stuck in place with spray glue. We spent under £40 to do the lot. We may even do the overcab roof when we get back to the UK.

Hope this may help.

steve & ann. -------------- teensvan.


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