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Narrowboat condensation during winter?

Can anyone suggest a solution to the condensation and high humidity problem in a narrowboat during the winter months. The humidity is constantly very high and the woodwork expands. I have used calcium chloride crystals in the special containers, but they make little impact. I don't want to run an electric dehumidifier over winter if I can avoid this. Has anyone any experience of the solar panel ventilation system by Solarventi?

Asked by: Philip Dale  | 10.04am, Friday 11 September

WW says:

Good levels of ventilation is the key! If you are living aboard, then plenty of high and low level vents are very important. If the moisture has nowhere to go, it will condense out, causing moulds, woodwork distortion, etc.
Another important point is keeping the air warm, preferably with a source of dry heat (like solid fuel stoves, or radiators). Gas cookers produce large amounts of moisture, as does washing, showering, or even just breathing! You need to be achieving total air changes of greater than 4 times the internal volume, per hour.
Solar vents can be useful, but better on unattended craft.
Anhydrous calcium chloride crystals will only absorb around 1 litre of water per 500g crystals. Considering that the 230V mains dehumidifier (which consumes 200W from the landline) can easily, in winter, extract 5 litres of moisture per 24hours, the crystal ones are next to useless on boats!
If you live aboard in winter, seriously consider a mains dehumidifier. If you don't stay aboard, leave a couple of windows open and ensure that your ventilation is up tp scratch!
As for double glazing on boats, it works. The other alternative is to ensure good sealing (varnish, etc) of the wood, and regularly wash and dry your curtains! The latter is a good long-term solution!

Mark Langley  | 10.10PM, Tuesday 15 September

Readers say:

I really want to know the answer to this! I am also in a quandry over hermetically sealed double glazed portholes which tend to fail over time in domestic situations versus single glazing with inevitable water staining below the windows through condensation

connol coan  | 4.35PM, Saturday 12 September

I agree with all Mark says except double glazing on a n/b. If it was a good idea we would all have it, as it is I suspect the takeup on D/G is less than 1%

Tony Bakinowski  | 8.16PM, Sunday 11 October

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