Good Dehumidifier

[paulk]

Unfortunately, I think all the cheap and easy ways of dehumidifying have conditions where they fail. The only 100% guaranteed solution that I can think of is to take a real heater and plug it into a humidistat switch.

Here's a breakdown on why I think the most commonly used tools fail. First, I'd point to this article by practical sailor that highlighted the main pain points:

http://www.practical-sailor.com/issu...s_11049-1.html

Let's go over these supposed humidity control solutions:

Peltier-based electric dehumidifier: The problem with these units is that they work by condensing water on a cooled plate. The cooled plate needs to be at a temperature below the air temperature of the room. Below a certain air temperature, the cooled plate will be cooled below freezing, causing the plate to frost up and stop working. Practical sailor researched this and found that none of the Peltier units were rated for temperatures below 65 degrees Fahrenheit. Practical sailor created a complicated scheme to add a defrost cycle by periodically unplugging the unit via a timer, but this would only be a stopgap measure and the unit still wouldn't work below a certain temperature.

Compressor-based dehumidifier: These have the same fundamental problem in that they work by cooling a plate to condense water. These units often come with a defrost cycle, so they can work down to 40 degrees Fahrenheit, which still leaves a lot of temperature range for mold to grow in cool climates.

Disposable chemical dehumidifier: A quick back of the envelope calculation shows me that a room temperature trailer at 100% humidity has about a cup of water in the air. I don't know how many air exchanges the trailer makes in a day, but I'd be surprised if it was less than 1 full air exchange, so you'd need to be capturing several ounces a day to make it work. My understanding is that chemical dehumidifiers typically collect less than that.

Reusable chemical dehumidifier: Practical sailor found that the desiccants also have an issue in that below 45 degrees they practically shut down since at that temperature the chemical reactions were very slow.

Warm air circulator – a look at humidity tables shows me that to reduce the relative humidity from 100% down to 60%, you need to raise the temperature by about 15 degrees Fahrenheit over a wide range of initial temperatures. I initially bought a 120 watt heater and have been trying it out for a while. My observation has been that it doesn't raise the interior temperature anywhere near 15 degrees Fahrenheit.

Since all of the above fail in cool temperature scenarios, the only solution left if you want a foolproof solution is to bring the temperature up by 15 degrees Fahrenheit with a real heater. You wouldn't want to run such a thing continuously since it would decimate your electricity bill, so combining it with a humidistat switch makes sense. In very hot and humid places you might instead or in addition want a compressor dehumidifier, or perhaps a Peltier dehumidifier.

I haven't bought such a system myself yet. I did however buy a simple humidistat that tells me the humidity. Even though I live in the Pacific Northwest I've been surprised that most of the time when I've looked at my humidistat it was reading about 60% humidity, so I’m not sure that I even have a problem during most of the day. The humidistat records maximums, so I know that I sometimes have humidity in the 90% range, but that seems rare.

If I end up buying some stuff to really do the job, I'll be getting these things:

Dayton Dehumidifier Control = https://www.amazon.com/Dehumidifier-...difier+control
Homebasix 700 watt oil filled radiator = https://www.amazon.com/dp/B001GDIXVI/?tag=jenrev-20

I think a 700 watt heater should do the trick, and it's a little lighter and more maneuverable to have a 700 watt heater than the 1500 watt heater that is more common.

I may instead just opt to do nothing to keep things simple. Not sure how bad an idea the "do nothing" option will be in practice.

[Fox hunt]

I have a little electric humidifier I picked up at an RV place I've also seen them on Amazon. I have to empty the water periodically but it really works well for the Pacific Northwest weather I hate that clammy feel with high humidity in the winter here. I think I paid around 50$ for it it's the small one.

[padlin]

You folks are getting g a bit deep for me. All I can tell you is the 20 pint that we have changes it from clammy to dry if you leave it on all day. It also heats it up a lot, which is fine when it's cool out, and Sometimes one needs to run the air at the same time.

This is for when we are using the trailer, not in storage.

[paulk]

To be a bit more clear, most dehumidifiers will work to some extent, and very well in some conditions, but not ALL conditions. I figured it would be useful to highight the conditions that are most problematic.

[War Eagle]

Thirty years ago, we purchased a Kenmore Coldspot compressor-style dehumidifier rated for 15 pints/24 hour (it's not that big but weighs a ton!) to pull the moisture out of a downstairs family room in a previous home we had just purchased. It still works great. Summertime in Alabama brings both heat (not going to add to that with a dehumidifying heater) and high humidity. I put it in our Escape 21' about once a month, and in a couple days, it will pull out up to 1/2 gallon of water. Seriously! You can really feel the difference. Once cooler Fall weather comes, humidity isn't that much of a problem here.
Point of clarification - using a heater simply keeps moisture present in the air within the cabin from condensing on surfaces, right? The moisture is still within the camper in vapor form, isn't it? If so, then calling the heater method a "dehumidifier" seems inappropriate. If moisture is still present in vapor form, it seems it would still be able to penetrate and saturate the woodwork, electronics, bedding, paper products, etc. If so, I'd just as soon use a method that actually removes the moisture, like we're currently using, not just let it linger around at a higher interior temperature where it still might cause problems. No science backing me on that - just my thoughts....

[cpaharley2008]

I leave one of these plugged in over the winter, keeps the trailer warm and dry....https://www.amazon.com/Davis-Instrum...2N872B4PH90BCY

[fudge_brownie]

If you are going to do any monitoring of temperature or humidity I would recommend the SensorPush. It is available on Amazon for $49 and requires a smart phone with free app.

The beauty of this unit is its ability to perform logging. It will hold up to 20 days of temperature and humidity readings. The readings can be as close as a minute apart. Second feature is you can trigger alerts when the readings reach a certain high or low. They have just released a wifi enable device that will send these alerts and readings to you anywhere you have internet access.

I have two of the units and they perform flawlessly. They are using the latest blue tooth technology and I have gotten readings from as far as 300 feet when unobstructed.

About the size of a half dollar, if anyone knows what they look like.

[War Eagle]

I don't know how anyone ever survived, much less had fun, camping before wifi and blue tooth!

[skiman]

Originally Posted by War Eagle

Thirty years ago, we purchased a Kenmore Coldspot compressor-style dehumidifier rated for 15 pints/24 hour (it's not that big but weighs a ton!) to pull the moisture out of a downstairs family room in a previous home we had just purchased. It still works great. Summertime in Alabama brings both heat (not going to add to that with a dehumidifying heater) and high humidity. I put it in our Escape 21' about once a month, and in a couple days, it will pull out up to 1/2 gallon of water. Seriously! You can really feel the difference. Once cooler Fall weather comes, humidity isn't that much of a problem here.
Point of clarification - using a heater simply keeps moisture present in the air within the cabin from condensing on surfaces, right? The moisture is still within the camper in vapor form, isn't it? If so, then calling the heater method a "dehumidifier" seems inappropriate. If moisture is still present in vapor form, it seems it would still be able to penetrate and saturate the woodwork, electronics, bedding, paper products, etc. If so, I'd just as soon use a method that actually removes the moisture, like we're currently using, not just let it linger around at a higher interior temperature where it still might cause problems. No science backing me on that - just my thoughts....

My older dehumidifiers lasted forever. The new ones seem to be junk. I have three now including the trailer. I have gone through 4 different ones, different brands in the last 6 years. They do work well for a while.

[Jake930]

Originally Posted by cpaharley2008

I leave one of these plugged in over the winter, keeps the trailer warm and dry....https://www.amazon.com/Davis-Instrum...2N872B4PH90BCY

I used a 400 watt heater this last winter. Plugged in the heater cracked the maxx fan just a bit, had no problems with condensation or mold.https://www.amazon.com/NewAir-AH-400.../dp/B009L40S0S

[cpaharley2008]

That is the one I use when it gets below freezing, turn the other one off.

[Jake930]

Originally Posted by cpaharley2008

That is the one I use when it gets below freezing, turn the other one off.

Great minds think a like!

[paulk]

Originally Posted by War Eagle

Point of clarification - using a heater simply keeps moisture present in the air within the cabin from condensing on surfaces, right? The moisture is still within the camper in vapor form, isn't it? If so, then calling the heater method a "dehumidifier" seems inappropriate.

True, heating isn't technically a "dehumidification" method since no water is being removed, however it is still effective at preventing mold from growing if done sufficiently. Mold can grow in humidity above 60% (the exact percentage is debatable), so to control mold you need to keep the relative humidity below that percentage. When you heat a room, the absolute amount of water vapor present in the air does not change, but since hot air can hold more moisture before condensing, the relative humidity drops, which prevents mold from growing.

Here in the PNW the humidity outside can be fairly high in the winter, however I routinely see 20% relative humidity indoors on my humidistat when the furnace is on. We sometimes even use humidifiers in the winter to keep our house comfortable.

[Brian B-P]

Originally Posted by War Eagle

Point of clarification - using a heater simply keeps moisture present in the air within the cabin from condensing on surfaces, right? The moisture is still within the camper in vapor form, isn't it?

Yes.

Originally Posted by War Eagle

If so, then calling the heater method a "dehumidifier" seems inappropriate.

I agree.

Originally Posted by War Eagle

If moisture is still present in vapor form, it seems it would still be able to penetrate and saturate the woodwork, electronics, bedding, paper products, etc.

That moisture typically isn't much of a problem as long as the relative humidity (as Paul explained) stays reasonable. Heating is not dehumidification, but it can address moisture issues, in some conditions.

[C&G in FL]

The Ecoseb I mentioned earlier will remove 15 pints per day. Let's face it, an Escape is not the size of a concert hall. If my 5.0TA hits 70% humidity, the Ecoseb will reduce the humidity to 45% within an hour or so. I have camped in 30° temperatures and if I have it running, I do not get any condensation on the windows or elsewhere.

[paulk]

Re-reading this thread, it isn't clear to me if the OP is concerned about controlling moisture while the trailer is occupied or while in storage.

If the trailer is occupied, then a compressor dehumidifier is going to be one of the best solutions since presumably the interior will be heated above 40 degrees Fahrenheit, and anyone inside the trailer will be generating more moisture than any of the other methods can extract. Heating can also work if the trailer is occupied, but you additionally would need to ventilate it because the moisture generated by the people inside needs to go somewhere.

[War Eagle]

Originally Posted by C&G in FL

The Ecoseb I mentioned earlier will remove 15 pints per day. Let's face it, an Escape is not the size of a concert hall. If my 5.0TA hits 70% humidity, the Ecoseb will reduce the humidity to 45% within an hour or so. I have camped in 30° temperatures and if I have it running, I do not get any condensation on the windows or elsewhere.

Carl, What does your Ecoseb weigh? Dale

[Kountrykamper]

13 pounds. I use the same one.

[Magnum]

Reading more than one paragraph makes me perspire. Thus exacerbating the problem.
Thanks for all the research and suggestions though.

[War Eagle]

Originally Posted by Kountrykamper

13 pounds. I use the same one.

Thanks, Tom. I need to go weigh my old Kenmore. I bet it weights more than twice that. Not fun to lug around.
Edit: Update: 47 pounds, and no real handle to speak of for carrying convenience. I think it was just meant to be put somewhere and left to do its job. And it does still do it's job! But for convenience, I may have to check into one of those 13 pound Ecoseb 15 pint'ers.