Author Topic: Dehumidifier advice (Read 1559 times)

Hutch · « **on:** July 23, 2012, 08:13:39 AM »

I have an 12x18 outbuilding that I use as a hobby room. It is not usually heated, but is air conditioned with a 5kBTU in-wall unit. It's reasonably well insulated, but it seems to be quite humid inside. I get rust on metal and verdigris on leather pretty quickly. My hypothesis is that the A/C isn't running enough to dry it out. I'm considering a dehumidifier, and my first impulse for these sorts of things is Sears.

I have no way to know just what capacity is called for, or what brand/model to choose. Y'all got any suggestions? I plan to run a drain line thru the wall.

280plus · « **Reply #1 on:** July 23, 2012, 08:18:00 AM »

Usually there are charts available from the manufacturer that should aid you in picking the right one.

280plus · « **Reply #2 on:** July 23, 2012, 08:21:35 AM »

http://www.davesrepair.com/DIYhelp/DIYdehumsizechart.htm

K Frame · « **Reply #3 on:** July 23, 2012, 08:53:39 AM »

You can try turning the AC on low and using a fan to circulate the air. It may be that the AC is setting up a static "cool zone" around the unit that's not allowing it to cycle properly.

If that doesn't work, remember that a dehumidifier will add heat to any room in which it's used.

Jim147 · « **Reply #4 on:** July 23, 2012, 10:58:52 AM »

I would start with a hygrometer. Take temp and humidity readings from a few different points around the building.

What are your outdoor temps and humidity running?

Is the A/C left running when your not using the building? Does it have an energy saver setting to turn the fan off when the compressor shuts off?

jim

Hutch · « **Reply #5 on:** July 23, 2012, 01:12:59 PM »

The building is a single room, just shy of 12x18. I have the a/c set at 74. It is an energy star model, but I don't know how it is set. I will investigate the links. I have no easy way to determine the humidity, but from my standpoint, even at 74F, it's easy to break a sweat with little activity. As stated earlier, holsters turn green.

thanks to all contributors.

ETA: by Dave's chart, even the smallest capacity shown on the Sears website should suffice. Neat!

grampster · « **Reply #6 on:** July 23, 2012, 02:17:18 PM »

I have a Frigidaire 50 pint model that works like a champ. My experience with dehumidifiers over the last 30 years would advise you to get a model NOT at the minimum required but one capable of working at a higher level. Makes them more efficient.

vaskidmark · « **Reply #7 on:** July 23, 2012, 03:28:03 PM »

Are dehumidifiers still the cesspools of fungii, virii and other vectors of death they used to be?

Isn't there an urban legend of someone nearly asphixiating themself with chlorine because of the bleach they added to a unit to counter the scum?

stay safe.

grampster · « **Reply #8 on:** July 23, 2012, 03:34:57 PM »

Takes about a day, plus or minus, to fill up the tank. I usually empty it each morning whether full or not.

Hutch · « **Reply #9 on:** July 23, 2012, 04:46:56 PM »

The chart I was sent a link to indicates that 12 pints/day will serve to remediate 500 sq ft that is very damp. My room is ~ 200sq ft, low ceiling, so I reckon the low end of the spectrum would more than suffice, unless I'm reading something wrong.

grampster · « **Reply #10 on:** July 23, 2012, 07:07:20 PM »

I agree.

brimic · « **Reply #11 on:** July 23, 2012, 10:28:08 PM »

We need a chart for dehumidifiers like the M4 chart.
I've gone through 5 dehumidifiers in 11 years, my latest that dies last week was a fairly expensive model and lasted just over a year.

Most of the dehumidifiers on the market seem to be cheap chinese junk with various brand names on them (GE, LG, Soleus, <insert POS store brand carried by Big Box Home Improvement Store>) that all leak all of their coolant out within 2 years .

never_retreat · « **Reply #12 on:** July 23, 2012, 10:38:46 PM »

An AC unit is going to cool the room and dump the moisture outside.
A dehumidifier is going to heat the room and put the water into a bucket. Which you need to empty or drain.
Your better off setting the AC a little lower and keeping the moisture down.

You need to see what the temp and moisture level is and adjust from there.

My house is usually set at 73 when we are home. When its cool out and the AC is not running it can get damp in the house. I just knock it down a degree or 2 to get rid of the sticky.

Azrael256 · « **Reply #13 on:** July 23, 2012, 11:23:14 PM »

I bought a 50 pint frigidaire like grampster's to dry out my master bath (it's poorly ventilated). The AC works fine in the summer to dry it out, but when it's 50 degrees out and it's muggy in the house, the AC isn't an option. 50 pints is WAY more than enough for a decent sized bathroom. I didn't know it would dry out a 2,500 ft2 swamp every 24 hours, I just bought the most efficient model I could find. It's oversized, but it works real, real quick.

I wouldn't use the water on anything but outdoor ornamental plants. I didn't take it apart to inspect the coils, but I suspect it's not food-grade stuff.

brimic · « **Reply #14 on:** July 23, 2012, 11:30:05 PM »

Quote

I wouldn't use the water on anything but outdoor ornamental plants. I didn't take it apart to inspect the coils, but I suspect it's not food-grade stuff.

Made in China- probably loaded with cadmium.

Jim147 · « **Reply #15 on:** July 23, 2012, 11:54:22 PM »

South Korea and South America have been big production spots for the little throw away units for many years now. NAFTA?

At my last company, we were a drop off repair location for most of the manufactures. I've worked on a bunch of them and they were good for teaching hands on refrigeration to new guys. Then they started looking at the numbers. They could make them and ship them to the US for well under $50.00 a unit, same for the small A/C units, so why stock repair parts and pay techs to recover, repair and recharge units.

I keep one around in case I have a water leak or something. It has a slow leak in the evaporator and a line tap on the process stub.

jim

Azrael256 · « **Reply #16 on:** July 24, 2012, 12:08:52 AM »

I'm no trade expert, but I'm reasonably certain that NAFTA isn't the reason.

280plus · « **Reply #17 on:** July 24, 2012, 08:04:45 AM »

You'll get longer cycles which equal better energy efficiency with a properly sized unit.

Hutch · « **Reply #18 on:** July 24, 2012, 12:44:27 PM »

Well, the window A/C is 5kBTU, so you can't get smaller. The room is reasonably cool, but damp. I will install a dehumidifier and a hose to drain. Thanks to all.

K Frame · « **Reply #19 on:** July 24, 2012, 12:51:53 PM »

"I wouldn't use the water on anything but outdoor ornamental plants. I didn't take it apart to inspect the coils, but I suspect it's not food-grade stuff."

The coils should be either aluminum or copper. No real cadmium issue there. Lead from the solder used on the copper tubing could be an issue, but not much of one.

I suspect that the water coming from a dehumidifier is going to be largely devoid of anything other than mold spores, dirt, etc.

I think in a pinch a dehumidifier could provide potable water. I'd want to run it through a filter first and then add a little salt and shake it up to get some air in it, though.

280plus · « **Reply #20 on:** July 24, 2012, 03:46:03 PM »

Let me be the first to say bleh...

Azrael256 · « **Reply #21 on:** July 24, 2012, 09:58:35 PM »

Well, if I am ever dying of thirst and I somehow have no water to drink but plenty of electricity to run my dehumidifier, I'll drink it straight.

Jim147 · « **Reply #22 on:** July 24, 2012, 11:00:07 PM »

I remember using dehumidifier water in science projects in high school. It is deionized but not purified. If you boiled it or used a filter, I think you would be alright.

jim

280plus · « **Reply #23 on:** July 25, 2012, 05:44:15 AM »

I didn't say I wouldn't drink it in a pinch, I just said, Bleh!"

K Frame · « **Reply #24 on:** July 25, 2012, 10:09:24 AM »

I have relatlively hard water in my area, so I pour the dehumidifier from the basement into the washing machine when washing whites. Helps cut down on the dingy gray color whites can take on when washing them repeatedly in hard water.

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Author Topic: Dehumidifier advice (Read 1559 times)