Dehumidfier against tube heaters

[Roy_374546528]

Hi there,

I have used a dehumidfier to remove moisture from the caravan over the winter. I run it for a few hours about once evry six weeks and get a small cup full of water.

Thus there is no heat at all in the van. Is it better to use this method of keeping the caravan dry or is it better to use a tube heater from time to time?

 

[Damian]

Roy, this subject has been discussed any times, and the general feeling is that as long as your van has no water ingress to start with, then a dehumidifer will be trying to dehumidify the planet as the fixed ventilation in vans means the air is constantly changing.

Similarly a heater wil be constantly trying to heat new cold air, so just wasting valuable money on electric.

As long as there is good ventilation and air circulation within the van, and the van is properly cleaned before storing, then there should be no reason to use anything.

 

[vauxhall2]

i use a small dehumidifier in our van,if feels dry and warm when you go in.many say i am trying to dehumidify the world but my point is it has to do the van first.

 

[ProfJohnL]

Hello Michael,

I understand your thought process, but I cannot agree with it.

Basically if the caravan is as it should be, with all its fixed ventilation slots unobstructed, the moisture laden air flow through the caravan will exceed what your dehumidifier can strip out.

Also if you do manage to make the environment inside the caravan drier than the air, then it actually become hydroscopic, and it will tend to attract moisture to it to redress the balance.

It is really a waste of resources to try and dehumidify a sound caravan in storage. - not to mention the power costs

 

[Lutz]

If at all, it only makes sense to use a dehumidifier or heater immediately prior to using the caravan, say in the 24 hours before going away.

 

[emmerson2]

Agree with JohnL. Its a bit like using a dehumidifier with the window open. The machine will actually attract damp air.

 

[Herv]

Houses also have ventilation slots.

Does it mean that using a dehumidifer in the house is also like trying to dehumidify the planet?

Not it doesn't...

So I think that using a dehumidifer in the caravan from time to time, or at least after a stay in it, does help.

 

[ProfJohnL]

Hello Herve,

The use of a dehumidifier is only of any practical use when for some reason the levels of humidity in the space are higher than the surrounding ambient level.

There is always a reason for raised humidity levels. In a house, it might be rising damp, or a hole in the rook or a broken down pipe etc, but fixing these issues removes the cause of moisture. The use of a DH may be desirable but will be long term to control these symptoms until the causes have been eliminated.

Other things relate to habitation, We tend to heat our houses to keep them warmer than the external ambient. Warm air can carry more moisture than cold air so it sucks up moisture, so when warm air from inside the house meets a cold surface (window or external uninsulated wall) the air cools and and it has to dump some of its moisture as condensation and thus moisture is transferred to the surface.

We all (including our pets) breath out warm air with a very high level of humidity, and burning gas in the cooker and oven also raises the humidity of the exhaust gasses This raises the over all humidity of the living space. As this is continually adding moisture, the use of a DH is not such a waste of time whilst the unit is occupied.

In times gone by, where open fires were the norm, the fire itself would create a positive ventilation process that moved large quantities of air through the living accommodation and dispelled the moisture laden air up through the chimney. Since most homes now have central heating the air exchange is much lower than it used to be so condensation in homes is a bigger problem now than it used to be.

I tend agree with you about using a DH in a caravan immediately after a holiday, but that is different thing to running a DH all the time during storage.

When the caravan is used, the level of humidity in the caravan and its structure will rise due to the habitation as outlined above.

So when you finish using the caravan after a holiday the caravans moisture level will be greater than one that had not been used.

Using a DH to bring the caravan back to the ambient level may well help, but prolonged use will have no appreciable effect.