KevinV
Well-Known Member
From the description that's not checking if it's drier outside, nor is it controlling a fan - although one could probably be rigged to the alarm function.
Mould while cruising
- Thread starter lustyd
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mjcoon
Well-Known Member
Yes, not so much a solution, more evidence of recognition that there's a problem!
lustyd
Well-Known Member
But then, two “weather stones” would achieve the same. If the indoor stone is wetter than the outside, open a window. If the outside stone is wetter, close it 
KevinV
Well-Known Member
You've just found the solution - rig the stones on a set of scales that operate a fan switch!But then, two “weather stones” would achieve the same. If the indoor stone is wetter than the outside, open a window. If the outside stone is wetter, close it
mjcoon
Well-Known Member
Ah, like those weather stations that have a man and woman pivoted so that one or the other emerges from their front door!
Weather house - Wikipedia
noelex
Well-Known Member
On a boat, you need a way to remove the moisture from sources such as humans breathing and gas cooking. The latter puts out a lot of moisture even without the moisture from the cooking itself.
The amount of water vapour in air is rather counterintuitive. Cold air feels damp because it can’t hold much moisture, so it’s usually close to its dew point. On the other hand, warm air feels drier because it can hold a lot of moisture.
Now, let’s talk about bringing in cold air from outside. Even if it’s almost full of moisture at its low temperature, when you heat that air, you’ll end up with warm air that’s dry and has a low relative humidity. This is why ventilation helps in cold climates, but don’t overdo it. If the interior cools down, the relative humidity can rise.
The amount of water vapour in air is rather counterintuitive. Cold air feels damp because it can’t hold much moisture, so it’s usually close to its dew point. On the other hand, warm air feels drier because it can hold a lot of moisture.
Now, let’s talk about bringing in cold air from outside. Even if it’s almost full of moisture at its low temperature, when you heat that air, you’ll end up with warm air that’s dry and has a low relative humidity. This is why ventilation helps in cold climates, but don’t overdo it. If the interior cools down, the relative humidity can rise.
