# Damp Problem 1 Dehumidifiers



## emjaiuk (Jun 3, 2005)

Has anyone experience of using a dehumidifier in a MH? 

I've got a heavy duty EBAC deumidifier left over from the last floods, and since I thought the MH felt slightly musty after the recent cold snap I thought I'd try it in the MH. In 48 hours it has filled the internal container (approx 5 litres) twice. That seems a lot of water to me from a MH which has no history of damp and it's last annual dampcheck at Essanjay was in August and was clear. There is a problem with one of the locker doors which I'm posting about seperately, but not 10 litres plus (It's still on)

Any comments from experience?

Malcolm


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## Jimblob44 (Oct 26, 2013)

I may be wrong but a dehumidifier of the type you are using will pull lots of moisture from the air and unless you can block all air vents the water it's collecting could be from the outside air coming in through vents or windows.?


Jim


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## emjaiuk (Jun 3, 2005)

I did think of that, but all the roof vents and windows are shut. There may be fllor level vents, but I've never seen them. I was more wondering if the average MH had areasonably high moisture conten in it's internal structure from condensation/cooking etc which a heavy duty dehumidifier is pulling out. As long as the internal walls dont crumble to dust :lol: 


Malcolm


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## Zebedee (Oct 3, 2007)

Motorhomes are like colanders Malcolm - there are lots of floor vents and other deliberate (and unintentional :roll: ) orifices to ensure ventilation for the occupants in even the coldest weather with everything closed up.

Apart from anything else, I think you have just proved the futility of the exercise. If the container keeps on filling up it indicates that however much water you remove, more moist air will keep getting in. If it didn't, the container would collect a small amount of water (nowhere near 10 litres!) once, and no more after that.

A pointless exercise I fear.

Dave


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## 747 (Oct 2, 2009)

Buy a box of Table Salt and put 2 or 3 saucers around the van.

When it goes 'crusty' stick it on a radiator to dry off, mash it up and re-use.

If it goes crusty within 24 hours, you have a damp problem.  

That is all I have ever used.


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## stevegos (Jun 23, 2013)

I had a little water ingress issue in the summer and borrowed a dehumidifier (after resolving the ingress). It extracted about 4 liters every day. I made sure every vent and every hole I could find was sealed so minimal outside air could come in.

I got a little suspicious that after 2 weeks (and about 50 liters of water) the exact same amount of water was still coming out of the fabric of the van. I put the extractor in the house and it produced the same amount. Took it outside and about the same amount again!

Bearing in mind the walls are coated in a vinyl coating which is designed not to transfer water I wondered if the water in the wall was even making its way out!


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## Spacerunner (Mar 18, 2006)

I use dehumidifier in the van every winter whilst the van is not in use. And it does extract a vast amount of water.
The reason I use a dehumidifier is not to dry out the interior air of the van but to prevent moisture being absorbed by the soft furnishings and prevent mould from forming in out of sight nooks and crannies.
The alternative is to strip out every last bit of fabric and frequent minute inspections of every little hidey-hole throughout the van for traces of mould or moisture damage.
On a wet day curtains etc can absorb a lot of airborne water. All it then needs is a bit of sunshine through the windows to evaporate the water back into the van's interior where it settles later in the day as it gets cooler and could lead to mould and mustiness.


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## dovtrams (Aug 18, 2009)

Another one for salt!

Dave


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## emjaiuk (Jun 3, 2005)

This particular dehumidifier was used in a two bedroom bungalow with suspended wooden floors that had about an inch of water over them from outside flooding. Although it took some weeks, it did in the end stop extracting noticable amounts of water.

Malcolm


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## robbosps (Mar 10, 2014)

Im trying the Unibond Aero 360 this year.

My friend had a brand new van and plugged her de-humidifier in. It was alweays filling up.


Dishwasher salt will be next years cheaper alternative!


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## raynipper (Aug 4, 2008)

I use a small dhumidifyer in ours on a timer. Two days a week as Spacerunnersays to stop fabrics from getting moldy. 
It probably draws out 5L in two weeks but I feel it's much cheaper than a heater.

Beware of sucking too much moisture out of the van as this can crack wooden panels and cabinet doors.
In our Arizona storage we had to do the reverse and keep 12 buckets of water inside the RV to stop the doors from cracking.

Ray.


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## deefordog (Dec 31, 2013)

At this time of year and on EHU, we always use a dehumidifier (Meaco DDL8) and set to approx. 60%. This keeps condensation at bay, helps dry clothes out and keeps the moisture levels down when cooking. Mostly on overnight and not used in the day when the weather tends to be a tad warmer.


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## rotorywing (Jul 19, 2010)

How do the hundreds of vans survive on the showroom forecourts?. Probably because they stay at one constant ambient temperature !.

Martin


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## GEMMY (Jun 19, 2006)

Will people stop trying to dehumidify the planet,

Google how to use them, along with temps. required

tony


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## Pudsey_Bear (Sep 25, 2008)

It's trying to dehumidify the planet, perhaps not a good idea, but a possible answer to future water shortages, perhaps we could save weight and produce water as needed instead of having heavy fresh tanks, I wonder if it could dehumidify the wast tank and make it re-usable.


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## Spacerunner (Mar 18, 2006)

Kev_n_Liz said:


> It's trying to dehumidify the planet, perhaps not a good idea, but a possible answer to future water shortages, perhaps we could save weight and produce water as needed instead of having heavy fresh tanks, I wonder if it could dehumidify the wast tank and make it re-usable.


The extracted water makes ideal steam iron water. Not quite had the nerve to try it for topping up batteries yet!
And, of course, the other big advantage with powered dehumidifiers is that they will swish the air around the van's interior thereby avoiding pockets of stale air, mould's best friend.


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## Pudsey_Bear (Sep 25, 2008)

Yes, two good uses for the output I'd not considered, must be kept in a none metallic container I think though, including the lid/stopper/top.

I did wonder earlier if you could drink the water produced this way despite it's origins, I suppose some would be a bit iffy, but not sure so I

Googled it


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## deefordog (Dec 31, 2013)

rotorywing said:


> How do the hundreds of vans survive on the showroom forecourts?. Probably because they stay at one constant ambient temperature !.
> 
> Martin


No one's living of cooking in them?


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## GEMMY (Jun 19, 2006)

No-ones are living or cooking in them when they are 'laid up ' either :wink: 

tony


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## Spacerunner (Mar 18, 2006)

GEMMY said:


> No-ones are living or cooking in them when they are 'laid up ' either :wink:
> 
> tony


So........no one's getting damp or mould/mildew problems then? :?


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## GEMMY (Jun 19, 2006)

That's all down to LACK of ventilation :wink: 

tony


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## Al42 (Aug 4, 2011)

Big difference in using a de humidifier in a laid up van and one in use, especially in winter.

I would take issue with the supposed fact that they have no effect unless in a sealed space, they surely have some effect depending on the efficiency and the amount of fresh damp air entering, they do not suck air in but recirculate. Much the same way that a fan heater will warm a space that is not sealed depending on energy level.


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## Zebedee (Oct 3, 2007)

> Al42 said:- . . . they do not suck air in but recirculate.


So after the first day or two when all the moisture has been removed from the recirculating body of air, why does the container continue to fill up??

Where does the continuing supply of moisture come from if no air is being sucked in?

Methinks 'tis not air that's being sucked in! :lol: :lol:

Dave


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## 747 (Oct 2, 2009)

There is always water in the atmosphere, it is called Humidity.

When the water is removed from an enclosure, the dampness in the rest of the air outside travels (imagine an invisible wick) into the enclosure because it is not hermetically sealed.

A dehumidifier just creates a temporary imbalance between inside the van and the outside.

Put a couple of bowls of salt down and open the windows now and again to get a draught through the van.


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## Al42 (Aug 4, 2011)

Zebedee said:


> > Al42 said:- . . . they do not suck air in but recirculate.
> 
> 
> So after the first day or two when all the moisture has been removed from the recirculating body of air, why does the container continue to fill up??
> ...


Ha **** Ha Sm********se

[/B][/I]Normal_* ventilation would account for a *_normal_* introduction of damp air from the outside.
The de humidifier has little effect on the introduction of fresh air, we are talking about a ventilated space*_


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## Spacerunner (Mar 18, 2006)

Just checked.

Humidity outside = 92%

Humidity indoors = 70%

Humidity in Motorhome = 50%. _Dehumidifier been running for four hours_

So something seems to be working :wink:


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## Al42 (Aug 4, 2011)

747 said:


> A dehumidifier just creates a temporary imbalance between inside the van and the outside..


Is the 'temporary imbalance' not exactly what is aimed for, it is self evident that fresh damp air will always enter a ventilated space.

When your salt crystals have done their work then the humidity levels will revert back to the levels outside the van, same as switching off the dehumidifier.


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## Al42 (Aug 4, 2011)

Spacerunner said:


> Just checked.
> 
> Humidity outside = 92%
> 
> ...


You must have been 'sucked in' to believing as well then :lol: :lol:


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## 747 (Oct 2, 2009)

Al42 said:


> 747 said:
> 
> 
> > A dehumidifier just creates a temporary imbalance between inside the van and the outside..
> ...


Not exactly.

eg: Damp rainy weather followed by warmer sunny weather. The damp air in the van warms up and precipitation occurs when it cools again (in the evening), leaving damp surfaces. The hard ones can dry off quickly but not bedding, seating etc.

The timing of using a dehumidifier can be important to prevent this. The Salt is there 24/7.

I don't really know why I am involved with this thread, I have never had a problem with dampness/Mildew/Mould.


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## Al42 (Aug 4, 2011)

747 said:


> Al42 said:
> 
> 
> > 747 said:
> ...


Neither have I, use a dehumidifier when necessary when we are in the van and use moisture absorbing crystals (more efficient than salt apparently) when not.


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## 747 (Oct 2, 2009)

Aha, I have just noticed that you have an articulated conveyance and are therefore more dependant on Sites (or a generator) as your wildcamping is a bit more limited. We do ours au naturelle without the modern conveniences you have at your disposal (that reminds me, I must find where I put my hookup lead). There is a world of difference in usage, if you are fulltiming then you will get a build up of condensation and my comments were aimed at winter storage not usage.

I hope you and your dehumidifier have a pleasant winter period.


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## Al42 (Aug 4, 2011)

747 said:


> Aha, I have just noticed that you have an articulated conveyance and are therefore more dependant on Sites (or a generator) as your wildcamping is a bit more limited. We do ours au naturelle without the modern conveniences you have at your disposal (that reminds me, I must find where I put my hookup lead). There is a world of difference in usage, if you are fulltiming then you will get a build up of condensation and my comments were aimed at winter storage not usage.
> 
> I hope you and your dehumidifier have a pleasant winter period.


Thank you for your good wishes  . we are in Portugal at the moment and........it is raining!!. Might have to put the dehumidifier on tonight. :lol:

I did try to point out in an earlier post the difference between using them when in storage and when in use.

I have never used one when the van has been in storage(crystals) but I do know they are very effective when living in the van, despite some peoples versions of the thermodynamics/physics involved. :wink:


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## Pudsey_Bear (Sep 25, 2008)

I don't know about dehumidifiers, some needs to demystify this thread.

Good ventilation, open everything inside the van, wash as many covers as possible, wipe down all hard surfaces with baby wipes, and blinds half way open/closed.


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## raynipper (Aug 4, 2008)

When bought this house as a holiday home some years ago. One bedroom was damp and we tried the crystals. But they soon became saturated and no longer worked. At least the dehumidifier kept sucking out moisture over the winter when we were not in residence until we cured the roof leak.

Ray.


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## Zebedee (Oct 3, 2007)

> Kev_n_Liz said:- I don't know about dehumidifiers, some needs to demystify this thread.


Almost spot on Kev, but it's not the thread that's the problem.

They are trying to de*mist*ify the van! :lol: :lol:


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## 747 (Oct 2, 2009)

Well I think it is outrageous that some people use power hungry electrical devices to reduce a bit of humidity temporarily. it is a flagrant waste of the Planets resources and they should be horsewhipped. :roll: 

Just sayin' :wink:


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## Al42 (Aug 4, 2011)

747 said:


> Well I think it is outrageous that some people use power hungry electrical devices to reduce a bit of humidity temporarily. it is a flagrant waste of the Planets resources and they should be horsewhipped. :roll:
> 
> Just sayin' :wink:


How dare you accuse me of being a power hungry site using non freeloader :wink:


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## 747 (Oct 2, 2009)

"How dare you accuse me of being a power hungry site using non freeloader".

It would have been simpler to just say 'idiot'.


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## Mrplodd (Mar 4, 2008)

In all then years I have owned motorhomes I have NEVER had a problem with damp/mould/mildew.

I never remove any of the furnishings or bedding, never put a heater or de-humidifier inside but I DO make sure its well ventilated.

It is very often unused for many weeks at a time.


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## Al42 (Aug 4, 2011)

Well I HAVE when using it and guess what, the dehumidifier actually helps.  

Single glazed glass windows, cold and wet outside, hot and steamy inside, even with ventilation, produces a lot of moisture in the air which condenses on the cold windows.Dehum mostly stops this.


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## 747 (Oct 2, 2009)

Al42 said:


> Well I HAVE when using it and guess what, the dehumidifier actually helps.
> 
> Single glazed glass windows, cold and wet outside, hot and steamy inside, even with ventilation, produces a lot of moisture in the air which condenses on the cold windows.Dehum mostly stops this.


We have looked at 5th Wheels but I never noticed they were single glazed. 

It must make quite a difference in cooler weather. :?


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## Al42 (Aug 4, 2011)

747 said:


> Al42 said:
> 
> 
> > Well I HAVE when using it and guess what, the dehumidifier actually helps.
> ...


They are not all single glazed it depends on the spec when ordering. We were in a bit of a rush when we sold the house and bought an ex demonstrator mainly because the lead time on a new one was about 3 months and we had to take what we could get regards specification.

I think a lot of the older RV's are also single glazed.

Fortunately the fiver is sited in Portugal now so the cold isn't as bad but still gets hot and humid some times.

We spent part of two winters in the UK when we first got it in 2008, site water froze, waste water manifold froze but I managed to thaw that, fortunately the electricity was OK for the dehumidifier :lol: :lol: more importantly for the heating though the furnace warmed things up quick but gobbled up gas( and chucked out loads of moisture  )


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## Zebedee (Oct 3, 2007)

Stone me Al, it must be pretty bloody boring in Portugal if all you have to do is try to convert us lot into dehumidifying! :lol: :lol: 

I've met Jehovah's Witnesses with less tenacity! 8O 

Dave :wink:


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## daffodil (Aug 7, 2014)

You are all so so wet banging on about this steamy topic :lol: :lol: :lol:


Where is the prophet in it (see wot I did there) :wink:


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## Zebedee (Oct 3, 2007)

He's in his own country - and there he can stay! :lol: :lol:


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## Al42 (Aug 4, 2011)

Zebedee said:


> Stone me Al, it must be pretty bloody boring in Portugal if all you have to do is try to convert us lot into dehumidifying! :lol: :lol:
> 
> I've met Jehovah's Witnesses with less tenacity! 8O
> 
> Dave :wink:


Persistence is my middle name, like a dog with a bone :lol:

Been back in Portugal a week now and I have a project!! trying to adapt an Omnistore safari room to fit under the fiver awning, almost done now just some bespoke decking(pallets) to finish off, slightly delayed by mini flood last night.

Jousting on forums brings some light relief (mainly to my back)


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## daffodil (Aug 7, 2014)

Zebedee said:


> He's in his own country - and there he can stay! :lol: :lol:


So that will be Portugal then :wink:


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## Al42 (Aug 4, 2011)

daffodil said:


> Zebedee said:
> 
> 
> > He's in his own country - and there he can stay! :lol: :lol:
> ...


Never been called a prophet before 8O :wink:


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## Zebedee (Oct 3, 2007)

Glad to see that you are not persist off with your life over there! :lol: :lol: 

We love Northern Portugal. Never been to the south and don't really fancy it if it's too touristy. It might be full of shops selling dehumidifiers!! 8O 8O 

Dave


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## Al42 (Aug 4, 2011)

Zebedee said:


> Glad to see that you are not persist off with your life over there! :lol: :lol:
> 
> We love Northern Portugal. Never been to the south and don't really fancy it if it's too touristy. It might be full of shops selling dehumidifiers!! 8O 8O
> 
> Dave


The Eastern end of the Algarve around Tavira is, believe it or not, not too touristy. We are here so there are some tourists but that's what keeps the economy going, plenty of 'Portuguese' stuff without having to look, a nice mixture for us.

The Alentejo is varied and large, by Portuguese standards, and the coast South from Vila Nova de Milfontes, Costa Vicentina is spectacular.

https://www.visitportugal.com/en/NR/exeres/40048323-D0A9-4FAC-B8A6-FEFFC9B4267F

Not seen any dehumidifiers down here :lol: :lol: ( but we bring ours)


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