Has anyone installed a built in dehumidifier?

[DDW]

Here in the PNW, humidity is a constant problem, even more so than in Florida. In Florida, you are running the A/C all the time which solves the problem. In the PNW it is wet and cool.

I know there are all manner of portable dehumidifiers and many people use them. This thread is not about those. There are a number of companies selling dehumidifiers with ducts, intended for permanent installation (in a house). The smallest of these would be appropriate for a boat, and in fact looks like it would neatly replace my port side A/C unit, utilizing the same wiring, ductwork, and drains. With no water cooled condenser, it could be run on the hard for storage.

Would I be the first person to put one in?

 

[boating rich]

Not a bad idea. We have installed some very small ones in our apartments that fit in a 16 inch wall cavity. They are 110 volt. My only concern would be the marine environment. Last I checked they are in the $600 price range.

 

[Ka_sea_ta]

The only problem that I have seen using dehumidifier in the PNW is if you have a Taiwan trawler that has wooden window frames It's possible to remove enough moisture that the wood will shrink and the windows will leak...

 

[DDW]

Not a Taiwan trawler, but in any case if set for around 50% you shouldn't shrink the woodwork. I'm tooling around Desolation Sound right now, practically the only boat up here but keeping the humidity below 70% indoors has been a battle.

I'm concerned about what they are made from as well, on the other hand the MarineAir air conditioner - an expensive marine unit - was made from aluminum except the drain pan which was made from steel, and is rusted through. I'm trying to understand that logic but have failed so far. Sometimes the only difference between household and marine is the price. I've seen several brands now, all 12 x 12 x 28 or thereabouts, $600 - $1200 range, 65 - 70 pints per day. They are about 600W draw on 110V, could easily be run from the inverter.

 

[sean9c]

Damp in the PNW is why all the oldtimers had Dickinson type stoves running 24/7. Have a friend who builds boats for the Bristol Bay fishery, all still use a Dickinson. One customer insisted on having hydronic heat and propane stove instead, that lasted one season. Had water running down the inside of the windows and nothing would dry. Replaced the propane stove with a Dickinson.

 

[Sabre602]

I have had great success in addressing VENTILATION on my boats. Using the natural physical properties of air, you can address humidity control quite effectively.

Cold air is relatively dry; it cannot hold a lot of water vapor. Warm air can hold immense amounts of water vapor.

On my boats I've done ventilation projects that take advantage of this simple fact. Using small "boxer" fans I draw in cold, dry air at the stern. As it passes through the boat, it is warmed (by whatever heater you have) and therefore absorbs moisture. The warmed, humid air is ejected at the bow.

At the dock the heat source is a small portable heater. When out on the saltchuck it's the Dickinson diesel (or, on my last sailboat, the Taylor kerosene bulkhead heater).

 

[DDW]

There are ways to heat a boat and ventilate it and get the humidity down some, but not the same as true dehumidification. And certainly not very energy efficient.

As an experiment yesterday, I ran the 16Kbtu air con unit in reverse cycle to heat set at 72 degrees, and the 12Kbtu unit set to cool at 68 deg. This kept the temperature about the same inside, but lowered the humidity fairly quickly from 65 to 48%. The difference in comfort was quite noticeable, as was the window fog and drying of everything inside. Not a real efficient way to do it, but verified that a dehumidifier is what I want.

 

[DDW]

Looks like someone has taken this up as a business opportunity. They are just using a rebranded household unit.

I have bought a household unit, will be installing it next month.

 

[Lepke]

I have a stove that runs 24/7 in the winter. My relative humidity usually runs 35-40%, currently 36 and the outside is 76. I also vent. My windows are custom wood, so low humidity doesn't bother them. At about 35% rh, I put on a tea kettle. Propane cooking is one of the biggest craters of moisture. Boiling spaghetti maybe #2.

On a non-liveaboard, a dehumidifier is a good choice.