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Old 02-06-2023, 10:44 AM   #1
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Dehumidifier...

The Admiral is convinced we need a dehumidifier on-board. I can understand one running whilst away, but when we are onboard either the windows are open, the A/C is on or we have the heat going so its either in-effective or redundant.

Thoughts?
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Old 02-06-2023, 10:49 AM   #2
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I leave one running in the galley sink when the boat is tied up in the winter but put it away in the summer. They draw quite a bit of power.
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Old 02-06-2023, 10:50 AM   #3
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Running a dehumidifier with the windows open would about as effective as running either A/C or heat with the windows open. That makes no sense.

An A/C IS a dehumidifier.

Forced hot air does a pretty darn good job of drying the air as well.

We only ever used a dehumidifier when the boat was closed and no A/C or heat running, which is typically when we were away for several days.
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Old 02-06-2023, 10:51 AM   #4
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The Admiral is convinced we need a dehumidifier on-board. I can understand one running whilst away, but when we are onboard either the windows are open, the A/C is on or we have the heat going so its either in-effective or redundant.

Thoughts?

Our dehumidifier is on while boat is in slip and we are not aboard. When we are on board the a/c is running and don't have the need to run the dehumidifier as well.
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Old 02-06-2023, 11:11 AM   #5
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I have a built in ducted dehumidifier and we run in a lot while on board. However that is in the PNW where it is cool and moist. The dehumidifier adds a small amount of heat and removes the moisture. In Florida, where either the AC will be running or the windows open, a dehumidifier will do nothing except consume power. Still good when you are away from the boat as it uses less energy to dehumidify than the AC.
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Old 02-06-2023, 11:19 AM   #6
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I just hope this doesn’t turn into another salty air thread.
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Old 02-06-2023, 01:19 PM   #7
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I just hope this doesn’t turn into another salty air thread.
lol, i remember that one.
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Old 02-06-2023, 01:58 PM   #8
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Yup. Your conclusions are my conclusions. Thanks Now I must (hopefully) transfer those thermo-dynamic conclusions effectively.

And about that salty air...
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Old 02-08-2023, 12:38 AM   #9
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Dehumidifier is one of the first things we got for new to us GB 42 in Puget Sound.
Eva dry desiccant, drains to sink. Works in lower temps than compressor types, they say. Runs on “auto” all the time. Interior Humidity has been consistently low to mid fifties. No condensation. Seems to work as designed.
Way down the road I would consider installing a built in one, also desiccant, like they did on MV freedom.
We don’t run this one underway.
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Old 02-08-2023, 12:27 PM   #10
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I leave one running in the galley sink when the boat is tied up in the winter but put it away in the summer. They draw quite a bit of power.
Sorry, but that sounds completely backward. Unless you live in some weird location, around here, humidity is not a problem during the winter, often, it is very low. Summertime, it usually runs very high. Now, if you keep your AC on for a good amount of time, I can see putting it away.
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Old 02-08-2023, 01:00 PM   #11
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I guess Juneau, Alaska is a weird location. Things get damp and mildewy in the winter. It’s not so much of an an issue in the summer.
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Old 02-08-2023, 05:24 PM   #12
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Sorry, but that sounds completely backward. Unless you live in some weird location, around here, humidity is not a problem during the winter, often, it is very low. Summertime, it usually runs very high. Now, if you keep your AC on for a good amount of time, I can see putting it away.
Where's "around here"? My boat is sitting in Anacortes, humidity is measured in 3 locations and uploaded every 15 minutes all winter long. It has been running about 70 - 75% with no dehumidifier running. I have the compressor type, it shuts down at around 45 deg to keep from freezing, and it's been colder than that for the last month.

Is 75% humidity a problem? Probably not as long as temps are in the 40s or below. Mold and mildew don't grow much then.
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Old 02-08-2023, 05:31 PM   #13
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Dehumidifier is one of the first things we got for new to us GB 42 in Puget Sound.
Eva dry desiccant, drains to sink. Works in lower temps than compressor types, they say. Runs on “auto” all the time. Interior Humidity has been consistently low to mid fifties. No condensation. Seems to work as designed.
Way down the road I would consider installing a built in one, also desiccant, like they did on MV freedom.
We don’t run this one underway.
Questions on your experience with the Eva Dry, I assume it is a rotary desiccant type. Do you know what the lifetime of the wheel is?

I was looking into the Ecor Por, which are a ducted unit seemingly idea for a boat (ss cabinet), but they state that the desiccant wheel has about a 4-5 year life, and a new one costs around $500 or $600 - half the price of the unit. This seems like a big drawback to the technology.
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Old 02-08-2023, 06:12 PM   #14
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Experience so far so good - same weather as your boat, and about 20-25% less RH in the boat this winter, only had it about 4 months. I bought the Eva-Dry Edv-4000H Rotary Desiccant Dehumidifier on amazon - $300 ish.

I'm not sure this one would be worth a new wheel. Didn't realize mine or even the more industrial ones like ECOR had to get a new wheel in 4-5 years.

good luck!
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Old 02-08-2023, 06:51 PM   #15
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An A/C IS a dehumidifier.

Forced hot air does a pretty darn good job of drying the air as well.

Air Conditioning does dehumidify, in that every 20 degree drop lowers the absolute humidity by 50%. Sending warm moist air past chilled coils will cause the humidity in that air to condense out. However, to gain that effect, one must actually be conditioning that air. In cooler temps, cooling the air results in cold, unhappy people.


AC-style dehumidifiers work by sending warm moist air past a set of chilled coils to cause the humidity to condense out, then sending that cooled dryer air past a set of heated coils where the waste heat of the prior cooling function is waiting to rewarm the air. Efficiency losses aside, the air comes out at the same temperature it went in, but with less humidity as that H20 has gone out the condensate drain. Using a dehumidifier in cooler temps doesn't result in cold, unhappy people unless further heating is needed.
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Old 02-09-2023, 11:05 AM   #16
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Experience so far so good - same weather as your boat, and about 20-25% less RH in the boat this winter, only had it about 4 months. I bought the Eva-Dry Edv-4000H Rotary Desiccant Dehumidifier on amazon - $300 ish.

I'm not sure this one would be worth a new wheel. Didn't realize mine or even the more industrial ones like ECOR had to get a new wheel in 4-5 years.

good luck!
Yeah, at $300 if you had to replace the whole unit every 5 years, not so bad. The only desiccant wheel ducted unit I've seen is the Ecor, it is considerable more expensive at about $1300, and replacing the wheel is expensive. Assuming they are around when you need to replace it. I want the ducted unit because I'd like to install it as I have the compressor unit, in the air conditioning ducting, so that it blows air throughout the boat.
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Old 02-09-2023, 01:52 PM   #17
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I realize there are a lot of folks here that are older and saltier than the MV Freedom crew on youtube but i think they do a good job and they have that early N43 pretty buffed out. Take a look at the episode where he installs one of those Ecor or similar dessicant dehumidifiers. didnt look too hard and they were very happy with it.
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Old 02-13-2023, 01:08 PM   #18
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In the shed and when at the dock We use a 110v home dehumidifier during the winter Just leave it on and draining out to deck .Different we usually have 4 to 6 people on board and it does pump up he moisture and running dishwasher and cooking . Come summer we might run it overnight so that the upper bridge windows are clear .
It helps keeping everything dry and fresh. I feel a few extra bucks on running it for the cost of your boat worth is worth it.
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Old 02-13-2023, 03:17 PM   #19
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The Admiral is convinced we need a dehumidifier on-board. I can understand one running whilst away, but when we are onboard either the windows are open, the A/C is on or we have the heat going so its either in-effective or redundant.

Thoughts?
You answered your own question. Your Admiral thinks you need a dehumidifier so OF COURSE you need a dehumidifier!

Tak
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Old 02-13-2023, 03:40 PM   #20
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You answered your own question. Your Admiral thinks you need a dehumidifier so OF COURSE you need a dehumidifier!

Tak
Yup…
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