Condensation - I didn't expect that would happen (1 Viewer)

[DavidG58]

Motorhome parked up at home, still plucking up courage to take for decent test drive before limping to France later this month, on hook up with Alde set to electric 1Kw, thermostat set to 12c, so no potential issues with freezing pipes

Went across today to have a quick look, we only see the back from our house, had a frost last night, cars white over, presumed same for MH but by now had thawed, but inside windscreen was covered in condensation, far more than we normally get when in use on cold nights

Karchered it, so all clear again, but why so much condensation with nobody in, the roof lights have built in vents and the Hartal lets a decent breeze round it , so think ventilation would have been good enough, no damp anywhere else, bedding feels nice, walls bone dry

I always presumed the main part of the condensation was us breathing our moist air, but not been slept in for 2 months

Should I be doing something different?

 

[GeriatricWanderer]

Do you leave the base vehicle heater/blower set to windscreen? (Not blowing of course but still letting some upward airflow).
I reckon ventilation is still the most likely culprit

 

[olley]

Wind chill? Wind goes past the windows and they suffer wind chill, moist air inside the motorhome condenses on them. As you have vents open more moist air can come in and do likewise. Maybe the answer is to seal it up like a drum? Then only one load of moisture to condense. Got me thinking now, not good.

Ian

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[sallylillian]

I have a small thermostatic controlled electric fan set on lowest to keep air warmish but moving and small dehumidifier set at 50% which needs emptying every 5-7 days.

 

[DavidG58]

I have a small thermostatic controlled electric fan set on lowest to keep air warmish but moving and small dehumidifier set at 50% which needs emptying every 5-7 days.

De humidifiers are scary things, I convinced myself many years ago they generate water to make themselves look effective

We have one in our tanked and dry lined cellar that drags about a gallon of water a week out of nowhere

 

[Puddleduck]

We use a small dehumidifier as well (Aldi had them in just before Christmas). It usually has a cup or so of water in every day We also use a very small oil filled radiator set just above the frost stat.

Last year I used one of the chemical dehumidifiers and that worked but not as well as the electric model.

When the van is unoccupied I don't use the internal thermal screens as I think that would mean less ventilation around the cab. In our van I think it would be impossible to block all the ventilation holes - even if I wanted to

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[DavidG58]

Do you leave the base vehicle heater/blower set to windscreen? (Not blowing of course but still letting some upward airflow).
I reckon ventilation is still the most likely culprit

I am on my way to check right now, seems a simple but potentially effective solution

just need the same conditions tonight to prove it

 

[robnchris]

We take all soft furnishings out of the motorhome over winter, open all the cupboards, fridge etc.
Never have any problems with condensation, if you heat the interior then warm air will settled on any cold surfaces and and you will get condensation, simple physics.

 

[DavidG58]

A follow up point, probably the same as most others though, all windows in our MH are double glazed except the windscreen, which is the only one to get the condensation

I don't pull the blinds

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[Jimbohorlicks]

I suspect your thermostat is too high at 12 C. This is extracting any moisture from the surroundings and because the windows are cooler ( direct contact with outside as it were) the moisture in the 12 C air is then condensing on the windows as opposed to elsewhere that is warmer. I would suggest a lower temperature setting would be better. The karcher would only put the condensate back into the warmer atmosphere in your van and will deposit the moisture again as condensate on the windows or anywhere that is cooler

 

[DavidG58]

simple physics.

it might be simple to you, physics and me really did not get on at school

actually simplify that, school and me didn't get on

 

[pappajohn]

Ventilation, not heat, is the cure for condensation.
Warm moist air will condense on a cold surface.

Keep the inside and outside temperatures the same and condensation cant form.

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[DavidG58]

I suspect your thermostat is too high at 12 C. This is extracting any moisture from the surroundings and because the windows are cooler ( direct contact with outside as it were) the moisture in the 12 C air is then condensing on the windows as opposed to elsewhere that is warmer. I would suggest a lower temperature setting would be better. The karcher would only put the condensate back into the warmer atmosphere in your van and will deposit the moisture again as condensate on the windows or anywhere that is cooler

I am on my way to open vents, will also drop the temp, we did use to set it at 8C not really sure why it got increased, or not lowered as far this year

the Karcher has only removed the condensation, it is one of the window cleaners

 

[DBK]

I suspect the condensation came from inside the vehicle, the cushions, any carpets or of course actual damp in the walls.

A chemical dehumidifier would be worth trying, not too expensive. Or of course borrow the one from your cellar for a few days. They don't make the water, they draw it out of the air. In the case of your celler it will be coming originally from the walls and/or floor. Tanked or lined as it may be.

 

[jezport]

Dont leave the heating on. You're making warm moist air which condenses once it hits colder surfaces.

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[DavidG58]

Ventilation, not heat, is the cure for condensation.
Warm moist air will condense on a cold surface.

Keep the inside and outside temperatures the same and condensation cant form.

I am right at the top of the lazy scale, by leaving heating on it saves dumping water, which I justify by being ready to pop off in at any moment, in reality not moved a wheel for 2 months and cost be a few £'s to keep warm

 

[robnchris]

I am on my way to open vents, will also drop the temp, we did use to set it at 8C not really sure why it got increased, or not lowered as far this year

the Karcher has only removed the condensation, it is one of the window cleaners

Most roof vents have a natural air flow through them, as will your floor air vents, so unless you have things covering the floor vents preventing and or restricting the air flow your motorhome should be fine just left as it it without any heating of course.

As for draining the water, it must take all of 5 mins to fill up the water so no bother really at all.

 

[Jimbohorlicks]

I am on my way to open vents, will also drop the temp, we did use to set it at 8C not really sure why it got increased, or not lowered as far this year

the Karcher has only removed the condensation, it is one of the window cleaners

Hi, not used a karcher but assume they are the steam ones for cleaning windows-I would suspect these will put more moisture into the air in your van and the upholstery etc. only for this to condensate when the air gets cooler or hits the windows on a cool day. You really need to remove the moisture from the air rather than just keep warming it up. open up the windows on a dry windy day.

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[DavidG58]

Hi, not used a karcher but assume they are the steam ones for cleaning windows-I would suspect these will put more moisture into the air in your van and the upholstery etc. only for this to condensate when the air gets cooler or hits the windows on a cool day. You really need to remove the moisture from the air rather than just keep warming it up. open up the windows on a dry windy day.

The Karcher we have is a battery powered suction pump with rubber blade, pretty nifty piece of kit for the bulk area of the windscreen, but no heat or steam involved

Agree with the opening up on dry day, will hope we get one before February we are planning to go away this month, hopefully best way to air it out providing we can keep the dog dry

 

[scousebird]

In 20 odd years of caravanning/MHing we have never heated or dehumidified whilst not in use. Neither have we removed anything or left cupboards doors open, in fact we pretty much leave it ready to go. Never had an issue with damp.

 

[Chris]

it might be simple to you, physics and me really did not get on at school

actually simplify that, school and me didn't get on

I got Grade 4 CSE in physics, so any problems give me a shout

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[DavidG58]

Most roof vents have a natural air flow through them, as will your floor air vents, so unless you have things covering the floor vents preventing and or restricting the air flow your motorhome should be fine just left as it it without any heating of course.

As for draining the water, it must take all of 5 mins to fill up the water so no bother really at all.

we have nothing covering our vents, but have an Alde heating system that I am yet to find out a way to drain the hot water, it has been boxed in in the garage area and needs the garage nearly emptying and a panel unscrewing to get to, the only way I can easily drain the hot water is run it all through the taps

Although fairly easy to refill, we even have a tap right next to where it is stored, the extra complication of draining the hot water and my inherent laziness means it stays heated, albeit now turned down to 6C

 

[DavidG58]

@Jimbohorlicks @GeriatricWanderer

thanks to guidance involving returning to the MH, I spent a few minutes hunting for the keys I had just used, then it dawned on me not only had I not locked it from earlier visit I have left the keys on the table, it would have stayed unlocked without these suggestions

on a related matter, ref insurance, since dropping my declared value to just below £50K I no longer need an alarm or tracker for the insurance to cover theft, not sure they would have been too happy at me leaving the keys quite so conveniently placed though , always worried me that if we forgot to set an alarm we would not be covered

 

[DavidG58]

In 20 odd years of caravanning/MHing we have never heated or dehumidified whilst not in use. Neither have we removed anything or left cupboards doors open, in fact we pretty much leave it ready to go. Never had an issue with damp.

excuse me, I don't think I used the 'damp' word, we have condensation on the windscreen, we have a continental A class, I would like you to know we don't have damp

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[scousebird]

I would like you to know we don't have damp

Neither do we
Neither do we get condensation on the windscreen when MH not in use

 

[Dawn B]

'Ere @scousebird @DavidG58 does not have 'damp' he is just wet behind the ears

 

[Badknee]

As we know all vans have vents, either in the base vehicle or the hab parts, vent, vents, vents. So, when you start up a dehumidifier it is sucking moisture out of the air it is dragging into the van through said vents. Even the driest of dry vans will end up with water in the collection tank.
IMO the OP has heated the inside of his van up and there was a big temp drop and as has been said 12c inside onto cold screen -2c is a 14c temp difference = massive condensation.

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[DavidG58]

there is probably a very good reason why, but with the price of the things why don't we get double glazed windscreens on our motorhomes

just sat here digesting Pauls comment above, firstly noting the complete lack of condensation on any windows in our house,despite running a 20C differential right now, but then drifted back to my childhood days something my kids and grandkids will never experience, the mountain scenes we had with ice on the inside of our windows in winter

 

[Badknee]

Yes David, that was pure body heat and breath, no heating in our house overnight exept the coal fire downstairs ' backed up'.

 

[Badknee]

Regarding d/glazed windscreens, they are about but massively expensive and very heavy.

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