Small Dehumidifier Recommendations?

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gcolton

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A couple of days ago I went out to my boat and found that the overhead was sweating. It is a 31' Pursuit express.

We have been having a lot of rain and cold. I think that when the sun hit the top of the cabin area it warmed up the overhead. The cabin was still cold and humid. That promoted the "rain" from the top.

I am thinking a small dehumidifier in the head would be good. It could just drain into the sump.

Anybody ever done anything like that? If so what dehumidifier did you use?

George
 
100 watt incandescent light bulb, burning 24/7 will do wonders in a small cabin.
 
I use a Caframo in Saint Max. Because it has a fan it circulates and dries the air. I am very satisfied with it and have been for 5 years. Depending on the size of the cabin and corners, you could supplement with goldenrods.
 
Dehumidifiers do not work too good if the temperatures are cool; they tend to freeze the coils. Once the coils are iced up they are useless. If the boat is stored for a period of time, just use a product like DampRid.
 
I used the smallest dehumidifier I could find at Home Depot in my last boat. It was a bit bigger and heavier than I wanted, but the price was much more reasonable compared to the ones made specifically for boats.

Completely eliminated humidity problems, but I did need to turn it off when it got cold outside. Since you are located in Florida the concerns about the coils freezing should not be an issue.

Mike
 
quote:
Originally posted by meide

I used the smallest dehumidifier I could find at Home Depot in my last boat. It was a bit bigger and heavier than I wanted, but the price was much more reasonable compared to the ones made specifically for boats.

Completely eliminated humidity problems, but I did need to turn it off when it got cold outside. Since you are located in Florida the concerns about the coils freezing should not be an issue.

Mike

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It is only when it is cold outside that I have a problem.

When you say cold outside just what temperature do you mean? I would not expect it to get below freezing in the cabin unless the outside temperature was at lease 20 deg. or below. What temp does it take for the coils to freeze up.

I need to do something because there was quite a lot of water dripping off the overhead.

George
 
Dehumidifiers typically don't work under 40 degrees F. Try a small heater instead.
 
Raising the air's temperature will lower the relative humidity but does not remove any moisture. You'll have to read the spec sheet of the dehumidifier to see it's operating range. If the cabin temperature gets up to the operating range during the day, the dehumidifier should work. I would plug the dehumidifier into a device that would only turn it on for a couple of hours during the day. Depending on the size of the dehumidifier, it should remove a couple of pints of moisture per day.
They do consume power. Smaller ones may draw 200 watts when the compressor is running; much of that power is given off as heat. If the cabin is warm enough for it to start to run without freezing the coils, then it should be able to run for awhile as it will heat the cabin's air temperature. The key is to get a dehumidifier that will work at low temperatures; some will start to freeze up when the air temerature is in the low 60's.
 
A dehumidifier is the friendliest thing you can do for the interior of your boat. We always had one operating on our boat, when we weren't on it, for over 40 years. We sat it on the counter and let it drain into the sink. We left locker doors and bilge access open.

Kept boat bone dry and free from mildew and odors.
 
I keep a 40-watt incandescent bulb burning in a clamp light all winter long. The light is located in the middle of the cabin. Use a larger bulb for a larger cabin. You want the waste heat from this lamp so be sure to use an incandescent bulb, not a CFB. The metal shade improves heat dispersion. Do not use in engine compartment. This is an inexpensive Ace Hardware store item.

pACE2-1153579reg.jpg


There are also a couple of Goldenrod dehumidifiers in smaller areas, including the engine compartment. These aren't that cheap in the larger sizes but they work great. Select the correct size for the area to be dehumidified.

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I've used this dehumidifier set-up every winter for at least ten years and never get condensation inside the boat even when the fog is hanging around for weeks. If water isn't leaking into the boat you don't need a lot of watts to prevent formation of condensation. The convection currents set up by these devices will drive out moisture and will stop condensation from forming. You would be surprised how fast a toilet bowl will dry out if a Goldenrod is placed next to it. A dry vent for a little free air circulation also helps.

Remember these are small dehumidifiers for a 26' wooden cruiser. You have to experiment to suit each boat under local conditions. I use no other heat on the boat. Right now air temperatures range from the low 40's to the 50's, water temperature is in the 40's and humidity is fairly high: condensation forms on the outside of the boat and completely wets the surface every day. This time of year the outside of the boat never dries out.

The downside of using a light bulb is that they burn out. I usually have one burn-out a winter. This is not a big deal since I usually check the boat at least once a week. A couple of winters used two bulbs up and I've had a couple of "magic" bulbs that lasted all winter without changing (24/7 November through March).
 
quote:
Originally posted by mandm1200

Raising the air's temperature will lower the relative humidity but does not remove any moisture. You'll have to read the spec sheet of the dehumidifier to see it's operating range. If the cabin temperature gets up to the operating range during the day, the dehumidifier should work. I would plug the dehumidifier into a device that would only turn it on for a couple of hours during the day. Depending on the size of the dehumidifier, it should remove a couple of pints of moisture per day.
They do consume power. Smaller ones may draw 200 watts when the compressor is running; much of that power is given off as heat. If the cabin is warm enough for it to start to run without freezing the coils, then it should be able to run for awhile as it will heat the cabin's air temperature. The key is to get a dehumidifier that will work at low temperatures; some will start to freeze up when the air temerature is in the low 60's.

Click to expand...


Heating the space will raise the temperature above the dew point and eliminate visible moisture.
 
quote:
Originally posted by dl2525
Heating the space will raise the temperature above the dew point and eliminate visible moisture.

Click to expand...

True, if all someone wants to do is eliminate visible moisture and not remove any of it. Keep in mind that condensation occurs when warm moist air contacts a cool surface. Warming the air keeps the moisture in suspension until it contacts cooler areas of the boat; cabin ceiling and outside walls. Removing the moisture will lower the dew point to prevent this. Mold and mildew like warm, moist air. Why promote this when others way will lessen it?
 
quote:
Originally posted by mandm1200

quote:
Originally posted by dl2525
Heating the space will raise the temperature above the dew point and eliminate visible moisture.

Click to expand...

True, if all someone wants to do is eliminate visible moisture and not remove any of it. Keep in mind that condensation occurs when warm moist air contacts a cool surface. Warming the air keeps the moisture in suspension until it contacts cooler areas of the boat; cabin ceiling and outside walls. Removing the moisture will lower the dew point to prevent this. Mold and mildew like warm, moist air. Why promote this when others way will lessen it?

Click to expand...


You are correct. I was just thinking that it's probably too cold to run a traditional dehumidifer since most areas are sub 40 degrees F at this point in the winter. In the spring/summer/fall time of the year, I agree with you 100%.
 
I read about the Davis airdrier in one of my boating magazines and decided to try it in the unheated space above our garage where we were having mildew problems with clothes stored there. I was a little leary because the uipstairs of the garage is open to the bottom and we have no insulation but it solved the mildew problem
 
MikeeH has a cat litter home recipe that many here swear by. Ping him for the recipe. I do not have it.
 
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