Dehumidifier

[Chasn]

Dehumidifier

I would like to rig up a dehumidifier to help keep dampness out of my motorhome during storage. Unfortunately it is stored in a building with no mains power. Whilst solar power is limited in its capabilities in winter there are enough hours of daylight to produce some energy. I see that some small dehumidifiers are just 20W but do remove some water from the air. Even if there was only enough power to operate a dehumidifier a few hours per day it might be enough to do something useful. A friend of mine used a solar panel connected directly to a small water pump which helped move water up to a large tank for irrigation. Whilst it only worked a few hours per day it was sufficient for the task. I am thinking that if I used a 100W solar panel there could be enough energy averaged over time to do useful work with a 20W dehumidifier. Many of these dehumidifiers have a container that has to be emptied. My plan is to run a hose from the bottom of the tank to drain to the outside. Has anyone done this before and does anyone have any advice on this?

 

[Deleted member 11]

Most de-humidifiers I have used on boats have a hose drain point which can be fed to a sink/shower tray.
Can't comment on the low wattage ones as ours were used over winter lay-up with EHU.

 

[Deleted member 155]

Most people don't realise that dehumidifiers need heat to work so putting one in a cold house or motorhome is really a waste of time and money.
Some models are designed to operate at low temperatures down to say 5 degrees C but a normal dehumidifier requires somewhere near 18 degrees C to operate or it will be in defrost mode most of the time .

 

[silverweed]

I stored motorhome for two winters in an outside compound. No problems what so ever. Left roof skylights ajar. Blinds closed, soft furnishings in place. No mould, no damp, no nasty damp smells

 

[GeoffL]

We also store somewhere with no electricity and have used rechargeable dehumidifiers (similar to the ones linked below) for over a decade. They've worked well for us. We have six -- three in use and three back home to be recharged, swapping them over every few weeks.

 

[Deleted member 155]

I stored motorhome for two winters in an outside compound. No problems what so ever. Left roof skylights ajar. Blinds closed, soft furnishings in place. No mould, no damp, no nasty damp smells

If you are leaving an empty van in the cold in the winter as you say just some ventilation is all that is required, the condensation really only becomes an issue when you heat the van , it is worse when the van is in use due to cooking, washing, breathing, etc .

 

[Barge1914]

Most people don't realise that dehumidifiers need heat to work so putting one in a cold house or motorhome is really a waste of time and money.
Some models are designed to operate at low temperatures down to say 5 degrees C but a normal dehumidifier requires somewhere near 18 degrees C to operate or it will be in defrost mode most of the time .

Agree with that, our Aldi dehumidifier froze solid even though the van was heated to 6 degrees.

 

[Deleted member 155]

The other thing to remember is if you are hearting and dehumidifying the van while not using it you really need to block all the vents like gas drop outs etc or all you are doing is trying to dry the planet !

 

[Bpoolmouse]

Why not just use throw away ones from the cheap shops( b&m bargains/poundstretchers etc).£1.00 each.
also dehumidyfier hanging bags for watdrobes.!

 

[fatwelshbuddha]

and have used rechargeable dehumidifiers (

a tip. don't drop one so that it breaks open or you'll have little beads everywhere and no matter what you do to collect them, they keep re-appearing! not that it's every happened to us - oh no.....:Wink_Emoji:

 

[JoeHymer]

DeHumidifiers certainly take lots of water from the air in the van, in my experience.
Is this really beneficial is the question that we need to answer?
Motorhomes are very "porous" because of the permanent vents; fridge, roof vents, floor vents etc. that are there by design, so that we don't smother and so that gas appliances have the air supplies required for safe operation. So, as we take the water out of the air, more fresh air enters through the vents and more water is collected and the cycle continues. This air exchange may be exacerbated by the fan in the dehumidifier drawing more air through the van from outside.There is, in effect, an infinite amount of fresh air to be dried and an infinite amount of water to be removed.
Using a Dehumidifier is certainly a reasonable option to consider, but probably should be operated continuously and drained to the outside, e.g. through a sink waste etc.

Perhaps two other alternative solutions are also worth consideration.
(i) Warm the air. This increases it's capacity to hold moisture. Hot air holds more water than cold air, so there is less condensation inside the van, when the air is warmer because it holds onto the moisture and there is less condensation. Should we put a heater in the van?
(ii) Increase the ventilation. This has the same effect as opening a window in a car. The increased ventilation helps to clear the moisture from the windscreen.
Should we open roof vents a little more?

Perhaps the optimum solution is to use a combination of all three, i.e. reasonable ventilation, some heat to prevent really cold air in the van and a dehumidifier with a drain to the exterior.

If I had to choose one, I would probably go for the ventilation option assuming the water systems are drained.
I guess it is also the option used by sales outlets for keeping their stock vans dry during winter.

Other members may, of course, have a different opinion or experience.

 

[Phillybarbour]

Never used one or felt the need to use one in 10years of motorhiming plus 10years with a caravan before.

 

[Trek]

Sure i saw these recently in Lidl’s

 

[raynipper]

I keep a mains dehumidifier running in our van all winter even though it's under cover and all vents and curtains are drawn.
I empty 2 litres of water every two days and the bedding is bone dry.

Ray.