De-humidifiers

[JWellington]

How does it work with marine dehumidifiers/air handlers? They take out moisture, but what about all the salt in the air? Our new boat will be tightly closed most of the time.

 

[O C Diver]

I've not had an issue with salt. I run a dehumidifier when not on the boat, that drain into the galley sink. No issues with corrosion. My boat air conditioners also don't show any signs of corrosion from salt in the air.

Ted

 

[Ken E.]

Same with me, salt has never been an issue, at least that I'm aware of. I also have mine in the galley with the drain going into the sink. Mine is a Danby and has worked fine for many years.

 

[guy with a boat]

How does it work with marine dehumidifiers/air handlers? They take out moisture, but what about all the salt in the air? Our new boat will be tightly closed most of the time.

What is your concern with salt? That it might corrode the dehumidifier, or something else?

 

[JWellington]

Thanks, but I guess I didnt express the question right. I'm not concerned with the machine being corroded but rather if all the salt in the air ...leaves with the water, is extracted along with the water. Indeed, even in areas near sea shores the air is salty and many dont like it, and its hard on various materials. So does a tight boat with modern air handlers have dry and salt free air?

 

[JWellington]

What is your concern with salt? That it might corrode the dehumidifier, or something else?

Jusst addressed while you were writing.

 

[DDW]

So does a tight boat with modern air handlers have dry and salt free air?

Yes.

 

[JWellington]

Yes.

OK, so then I guess the physics of it is that the salt is in the moisture/water, and thus gets extracted along with it.

 

[JWellington]

None of the boats ive had, have even had modern air handlers, nor have i ever even heard this aspect mentioned. So in addition to the dry air being better for my wifes hair(or whatever shes talking about), it should also be better for the electronics, etc.

 

[psneeld]

While I believe dehumidification reduces both water vapor (and it's salt aerosols), there is still salt aerosols in the remaining water vapor.


Research has shown salt aerosols as far inland as 100 miles (in Florida).

 

[JWellington]

While I believe dehumidification reduces both water vapor (and it's salt aerosols), there is still salt aerosols in the remaining water vapor.


Research has shown salt aerosols as far inland as 100 miles (in Florida).

OK thanks. And I guees you mean in whatever moisture still remains. I like dry air, like 20% or so, but that still means some moisture, some salt. But it must be much less, right? More research to do.

 

[psneeld]

https://theozonehole.com/what-causes-low-humidity-in-a-house.htm

According to the environmental protection agency (EPA), it is best that indoor relative humidity is kept below 60% at all times. Though 60% is the threshold, the actual range spans around 40% to 50%, with an allowance for a little higher or lower, i.e., 30% and below 60%. This variation is also temperature sensitive too.

What happens when humidity is low: Low humidity in the house symptoms

Now that we have known What causes low humidity in a house, what are the consequences. Exposure to very low humidity levels can be a major causative factor of poor health conditions. Poor sinus health is one of the major symptoms experienced by people living in low humidity, which leaves the sinus very dry due to lack of moisture in the air, making it more susceptible to diseases and allergens.

There is also an issue of severe respiratory problems, which is due to the low moisture that, over time, can inflame the mucous membrane that lines your respiratory tract. This is a very sensitive membrane; therefore, inflammation could cause more problems, significantly increasing the risk of infection like a cold or flu. The flu virus survives longer, and also spread faster in decreased humidity. Other symptoms include dry and itchy skin, red, sore, and itchy eyes too.
Low humidity headache: A major Discussion

According to the world health organization (WHO), headaches are the single most common nervous system disorder, with statistics which shows about 1 in 2 adults experience this at least once in a year. There are several potential factors which could be responsible for the nervous disorder that causes headaches in the body, with stress precisely topping the chart. However, there is a chance that the headache you feel is as a result of low humidity.

Low humidity is able to cause nervous disruption, resulting in headaches after prolonged exposure. It starts with nasal dryness, whereby the mucus membrane will dry out, and starts to develop cracks, till a point where they become irritated and eventually inflamed. The resulting swellings make it difficult for blood to flow at the normal rate as it would through the sinus cavities, causing a pounding headache in the process.
Low humidity could also be responsible for causing headaches by becoming an avenue for repulsive chemicals to exist in the atmosphere. Most common household items like furniture, new materials, paints, and others, actually contain toxic residues of chemicals used during the manufacturing process. The molecules of these chemicals are trapped on the surfaces, and sometimes can be smelt. Very dry air causes the dangerous chemicals to evaporate into gas form, making them available for pickup by the simple act of breathing in. This gas inhaled in large quantities may trigger headaches and other health problems.

 

[JWellington]

Not for everybody, and its why some prefer to live in Arizona or Utah etc. Thats why I feel better at my brothers place in Salt lake city, than Seattle or Portland maine. In any case on boats with modern air handlets the humitity can be set to whatever one likes best.

 

[Marco Flamingo]

Our new boat will be tightly closed most of the time.

Yes, that will cause moisture problems leading to mold, mildew, and odors, but not because of salt or being near saltwater. Temperature differentials inside the boat will cause the natural moisture in the air to condense against colder surfaces. These water droplets will be similar to distilled water, i.e., relatively pure with little or no salt. If the water droplets never completely evaporate because the boat is tightly closed, it provides the moisture required for the growth of mold and mildew. If the water was salty, it would not. If the boat had adequate ventilation, it would not.

 

[psneeld]

To get to 20% humidity on a boat...better buy at least 2X the expected capacity or 2X the units.


Even then they may never reach 20%.

 

[guy with a boat]

Yes, that will cause moisture problems leading to mold, mildew, and odors, but not because of salt or being near saltwater. Temperature differentials inside the boat will cause the natural moisture in the air to condense against colder surfaces. These water droplets will be similar to distilled water, i.e., relatively pure with little or no salt. If the water droplets never completely evaporate because the boat is tightly closed, it provides the moisture required for the growth of mold and mildew. If the water was salty, it would not. If the boat had adequate ventilation, it would not.

None of this happens if you keep the humidity down. Lock it up tight and keep the interior dry with dehumidifiers and you will be good. Ventilation in a humid climate just brings in more moist air.

 

[psneeld]

So JW, what kind of boat did you get?

 

[JWellington]

Yes, that will cause moisture problems leading to mold, mildew, and odors, but not because of salt or being near saltwater. Temperature differentials inside the boat will cause the natural moisture in the air to condense against colder surfaces. These water droplets will be similar to distilled water, i.e., relatively pure with little or no salt. If the water droplets never completely evaporate because the boat is tightly closed, it provides the moisture required for the growth of mold and mildew. If the water was salty, it would not. If the boat had adequate ventilation, it would not.

Addressesd by air handlers, they ventilate and dehumidify.

 

[psneeld]

Addressesd by air handlers, they ventilate and dehumidify.

Actually most only recirculate and remove moisture as pointed out by Guy with a boat.


Some will discuss how the humidity inside versus outside needs ventilation/makeup air..... but every situation has to be about moisture inside versus outside to see if makeup air is best. With people inside, usually it is for various reasons.


What brand air conditioners and boat do you have?

 

[JWellington]

So JW, what kind of boat did you get?

A shortlist of 4, whichever, will have proper air handlers. And that some dehumidifiers "only recirculate inside air".....that doesnt describe modern air handlers at all.

 

[JWellington]

To get to 20% humidity on a boat...better buy at least 2X the expected capacity or 2X the units.


Even then they may never reach 20%.[/QUOT

Apparently can, but even say 30-35% is fine.

 

[Marco Flamingo]

Ventilation in a humid climate just brings in more moist air.

I've only had boats in the Pacific Northwest, so it has never been a problem.

If ventilation just brings in more moist air, wouldn't my boat inflate and explode? That's also never been a problem. Apparently my passive ventilation is more complex than I thought, although not as complex as the mechanical/chemical dehydration gizmos. I sold all the Damp Rid, Golden Rod, Air-Dryr stuff the prior owner had on board. I suppose I could have installed an even more complex system of dehydration gadgets, but I went the other direction. Going on 2 years without a problem.

 

[Marco Flamingo]

Ventilation in a humid climate just brings in more moist air.

I've only had boats in the Pacific Northwest, so it has never been a problem.

If ventilation just brings in more moist air, wouldn't my boat inflate and explode? That's also never been a problem. Apparently my passive ventilation is more complex than I thought, although not as complex as the mechanical/chemical dehydration gizmos. I sold all the Damp Rid, Golden Rod, Air-Dryr stuff the prior owner had on board. I suppose I could have installed an even more complex system of dehydration gadgets, but I went the other direction. I added two vents in the cockpit and modified a forward hatch cover so that it could be left open 2 inches without letting in spray or rain. Going on 2 years without a problem.

 

[JWellington]

I've only had boats in the Pacific Northwest, so it has never been a problem.

If ventilation just brings in more moist air, wouldn't my boat inflate and explode? That's also never been a problem. Apparently my passive ventilation is more complex than I thought, although not as complex as the mechanical/chemical dehydration gizmos. I sold all the Damp Rid, Golden Rod, Air-Dryr stuff the prior owner had on board. I suppose I could have installed an even more complex system of dehydration gadgets, but I went the other direction. I added two vents in the cockpit and modified a forward hatch cover so that it could be left open 2 inches without letting in spray or rain. Going on 2 years without a problem.

No, air handlers will not inflate your boat to exploding point. What they do is treat the air, make it warm or cold, dehumidify it(and tes, that takes salt out of the air! Its amazing , but engineers have figured all this out already. My original point was only about salt .

 

[psneeld]

No, air handlers will not inflate your boat to exploding point. What they do is treat the air, make it warm or cold, dehumidify it(and tes, that takes salt out of the air! Its amazing , but engineers have figured all this out already. My original point was only about salt .

Much more reading and experience is necessary. There's always more to the story.


This is just another topic where you think know more than the people you ask questions of.

 

[guy with a boat]

I've only had boats in the Pacific Northwest, so it has never been a problem.

If ventilation just brings in more moist air, wouldn't my boat inflate and explode? That's also never been a problem. Apparently my passive ventilation is more complex than I thought, although not as complex as the mechanical/chemical dehydration gizmos. I sold all the Damp Rid, Golden Rod, Air-Dryr stuff the prior owner had on board. I suppose I could have installed an even more complex system of dehydration gadgets, but I went the other direction. I added two vents in the cockpit and modified a forward hatch cover so that it could be left open 2 inches without letting in spray or rain. Going on 2 years without a problem.

Ventilation will gradually equalize the humidity inside and outside. In the PNW, there are many winter days with humidity levels over 95%. When you are on the boat and heating the interior, that same air, when heated, is at a much lower relative humidity inside so it is comfortable. When you leave the boat, the temps inside and out equalize and so does relative humidity. High levels of humidity over time will result in mold and mildew problems inside, regardless of air movement (ventilation). Ventilation is effective against mold/milder when you are bringing in dryer air, but not when you are just maintaining high moisture levels.

Talk to dock neighbors and boat friends in the area, and you will likely find that most are using some type of dehumidification. We have 2 condenser-style dehumidifiers that we use when away from the boat, in addition to small heaters and fans. Relying on ventilation alone might have appeared to work for you for 2 years, but almost certainly will allow bad things to happen over time. In the best case, your boat will develop a bad case of “old boat smell” over time.

 

[Jeff F]

No, air handlers will not inflate your boat to exploding point. What they do is treat the air, make it warm or cold, dehumidify it(and tes, that takes salt out of the air! Its amazing , but engineers have figured all this out already. My original point was only about salt .

I think you're mistaken about salt. Dehumidifiers do not remove salt from the air. They take water from the air, and that water doesn't have salt in it.

Just for fun, taste the water coming out of the demudifìer. There is no salt in it.

 

[DDW]

Salt doesn't get evaporated and mixed with the air in gaseous form. Sea water can get turned into an aerosol - tiny droplets - and blown over the sea and inland a ways. When they are present, these should mostly get trapped by the dehumidifier and will be washed out the drain. By constantly bringing in outside air rather than recirculating the indoor air, you will be bringing in much more 'salt air'.

I have run dehumidifiers on boats for about a decade, currently two boats, always the recirculating kind and I think it is quite beneficial. The upholstery feels dry, nothing molds, towels and foul weather gear dries, things don't corrode. You don't feel sticky after a shower.

I've never seen a small recreational boat built with the kind of 'air handlers' you describe. In fact it is pretty rare even in residential construction. Nearly all air conditioning systems recirculate air, it takes a lot of power to do otherwise.

 

[JWellington]

Much more reading and experience is necessary. There's always more to the story.


This is just another topic where you think know more than the people you ask questions of.

I showed that I know more than the guy who thinks a boat could explode from being overpressurized by the airhandler. Wait a minute, did you also think that could happen?

 

[JWellington]

Salt doesn't get evaporated and mixed with the air in gaseous form. Sea water can get turned into an aerosol - tiny droplets - and blown over the sea and inland a ways. When they are present, these should mostly get trapped by the dehumidifier and will be washed out the drain. By constantly bringing in outside air rather than recirculating the indoor air, you will be bringing in much more 'salt air'.

I have run dehumidifiers on boats for about a decade, currently two boats, always the recirculating kind and I think it is quite beneficial. The upholstery feels dry, nothing molds, towels and foul weather gear dries, things don't corrode. You don't feel sticky after a shower.

I've never seen a small recreational boat built with the kind of 'air handlers' you describe. In fact it is pretty rare even in residential construction. Nearly all air conditioning systems recirculate air, it takes a lot of power to do otherwise.

Somebody above testified that salt laden sea air can be blown a hundred miles inland. Nobody mentioned "small recreational boat" at all. And we've verified that modern airhandlers do indeed take out salt as well as moisture, they dont just recirculate it, they dont inflate boats to point of exploding, and they work really well, especially in tight, well insulated boats.