Frugal Dehumidifier - any good models widely available?

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I've been looking for a good dehumidifier and I notice that each big box store only really carries one brand and there really isn't much online as far as reviews. I know some dehumidifiers are energy hogs and some are very loud can anyone recommend a dehumidifier that they are happy with? I have an 800 sq/ft basement that I'm looking to cover and the temp can go as low as 55 degrees in the winter.
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How about a Crawlspace Smart Vent?
http://www.smartvent.net
They cost $365, but they only use 40 watts when moving 290 cfm of air out of a basement when the absolute moisture content of basement air is greater than the absolute moisture content of outdoor air.
To also heat (cool) a house in a cool (warm) season, we might power up the Smart Vent with a differential thermostat only when outdoor air is warmer (cooler) than house air.
Nick
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...

Does that mean when the absolute moisture content is the same (high or low) it does noething? Seems like it would have limited value in a naturally humid region whee you want to make it lower.

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The technical description on the crawlspace web page says they evacuate crawlspace air when its RH is more than 35% and the absolute moisture content of the outdoor air is lower than that of the crawlspace air. They also evacuate crawlspace air when the crawlspace RH is less than 25% and outdoor air has 20% more absolute moisture. They say adding humidity to a crawlspace is sometimes useful to keep it from drying out to the point that hardwood floors buckle.

Yes. This might work well in a climate with some humidity variability and with a fairly airtight crawlspace and some building materials that can store moisture. It would work better in Chattanooga (wmin = 0.0036 in January) than Key West (wmin = 0.0100 in January.)

Yes. It only works on dryish days. There's a nice graph of crawlspace humidity over time on the web site.
Nick
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Thermastor makes the most efficient dehumidifier, according to Energy Star. Costs a lot but can pay for itself in energy savings. When I bought mine, it was twice as efficient as the models sold at Sears. I use it to dry out my swamp of a basement. It's somewhat noisy, but apart from that I have no complaints.
http://www.thermastor.com/Santa-Fe /
The powered vent that Nick recommends would be a lot cheaper to buy and to run, assuming it can be used in your application.
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Au contraire. It will, with suitable weather conditions and controls and building materials that can store moisture and dryness, eg paper and wood and clothing and concrete with suitable sorption isotherms.
Concrete stores about 1% moisture by weight as the RH of the surrounding air increases from 40 to 60%, and it weighs about 150 lb/ft^3, so a 4"x1000ft^2 50K pound floorslab might store 500 pints of water as a basement RH increases from 40 to 60%.
Smart Vent's 12/19/2000 US patent no. 6,161,763 "Module-controlled building drying system and process" at http://www.freepatentsonline.com describes
"...drying air circulation between inside and outside the building based on absolute humidity and temperature sensor measurements... the input ports are connected to... outside absolute humidity sensors... [and] inside absolute humidity sensors [and] the output ports are connected to... [a fan system.] ...if the outside air has a lower absolute humidity than the inside air... the fan system output will be activated... if the outside air has a higher absolute humidity than the inside air... the fan system will be shut down."

Yesterday it was 67.8F with 41% RH in my house with some windows open, so the vapor pressure Pi = 0.41e^(17.863-9621/(460+67.8)) = 0.284 "Hg. The indoor humidity ratio wi = 0.62198/(29.921/Pi-1) = 0.00597 pounds of water per pound of dry air. The outdoor sensor in partial sun read 84.0 at 19%, so Po = 0.181 "Hg and wo = 0.00379, so every pound of air that flowed through the house removed wi-wo pounds of water.
A Smart Vent could have removed 290x60x0.075(wi-wo) = 2.8 pints of water per hour, at 70 vs 3.7 pints per kWh.
To also heat (cool) a house in a cool (warm) season, we might power up a Smart Vent with a differential thermostat only when outdoor air is warmer (cooler) than house air.
And we could hook a relay in parallel with the Smart Vent fan to power a whole house fan, and add house room air thermostats to shut off the fan if the house becomes too warm or too cool.
Nick
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On 24 Apr 2007 01:00:42 -0400, snipped-for-privacy@ece.villanova.edu wrote:

yeah, that's all well and good if you're starting from scratch. But neither he nor I are. We both have existing buildings with moisture problems and not amount of math will solve the problem.
In addition to using the best available construction techniques back in the early 70s when we built the place, over the years I've had the foundation dug out, French drains installed, the block walls tarred and polyethylene sheathed and gravel backfill placed next to the house. Plus painting the inside walls with water-stop paint. The walls and slab are STILL moist to the touch. There's simply too much water in the ground, too much flora to hold it in place and almost no sun to drive it off.
I ventilated the basement with far more air flow than your $360 gadget provides and it made no difference in either the mold growth or the measured RH.

Another worthless rubber-stamp patent issued in spite of vast amount of prior art. Disgusting.

You don't have anything nearly approximating a moisture problem. You live in an arid environment as evidenced by those outdoor readings and only need a little humidity management, something that throwing open the windows will probably accomplish. We, OTOH, have many "95-95" days - 95 degrees and 95% humidity. Your overpriced hair dryer blower won't touch that.

For about 2/3rds the cost of that so-called smart vent, one can install a whole house attic fan and actually move some air. Which is precisely what I did years ago. In my case, equipped with a PMDC motor and variable voltage drive. I can spin it at ceiling fan velocity and generate a gentle draft-free air exchange or I can crank it up and sail the drapes. And still have much money left over compared to that gadget.
None of this addresses a moisture problem in a basement, of course. In my case, in the 30 years this cabin has been in existence, this is the first year the basement has been dry enough to store valuable goods such as electronic gear and books. That's thanks to a dehumidifier that costs less than half your fan and uses only slightly more power.
I don't understand your abnormal advocacy of that little fan. Do you have a financial interest in the product?
John
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Sounds like you have enough concrete, but few dry days... 500 pints is only 10 days at 50 pints per day.

Unsmart venting can *add* moisture to basements by condensation.

This technique was quite useful in New Orleans after Katrina. By law (US Code 102/103), the patent would not have been issued if it were not novel.

That's 67 pints per day with less than 1 kWh.

I wish they made a version like that, with a "season sensor" to change the sense of the differential thermostat.

Philadelphia? :-) As I mentioned above, that outdoor temp/RH sensor was in partial sun. The outdoor temp was 76 in the shade, which made the outdoor RH about 25%, rare but nice here in the spring. This morning it's 64.6 F and 55% outdoors.

We have a few nights like that in August.

It works well in humider Arkansas, where it was developed.

But then you have to do all those horrible calculations every day. You want to remove more than 67 pints per day?

Of course it does, precisely.

No, but I've been trying to help get a product like this to market for several years now, since Murray Milne and Pablo LaRoche from UCLA gave a talk on a "smart whole house fan controller" at the ASU Cooling Frontiers symposium. Their box (with an Onset Tattletale controller) automatically cooled a massy test house by ventilation, but it didn't address humidity. With RH sensors, we can efficiently dehumidify and also cool and warm houses with outdoor air, with no danger of indoor condensation.
Nick
Berlin is a nice town and there were many opportunities for a student to spend his time in an agreeable manner, for instance with the nice girls. But instead of that we had to perform big and awful calculations.
Konrad Zuse, inventor of the 1936 Z1 computer
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On 24 Apr 2007 06:41:25 -0400, snipped-for-privacy@ece.villanova.edu wrote:

And if you believe that, I have some nice oceanfront land in TN to sell you. Do you think that the patent for the common tree swing was novel? How about the "cat exerciser", chasing a cat around with a laser pointer? Reckon there was any prior art? How 'bout the Nexium patent that, when all the verbiage was stripped away, covered a slightly different shade of purple from its predecessor, Prilosec? Thankfully, that one got slapped down after someone requested a reexamination.
In computer science, the infamous "XOR" patent that covered a basic screen update technique that had been in common use for years. All issued in the last 10 years. Or the recent patent office chief, can't recall if it was GW's or Clinton's, who said publicly that they didn't have enough manpower to examine patents anymore so they were issuing almost all and would let the courts work it out?

Really? Let's do a test, sort of a worst-case one. Obtain one of those fans and send it to me. I'll install it along with data logging equipment and we'll see what it does in this environment. I have several HOBOs including the temperature and RH one. I'll buy the duty cycle one to log the fan run time. I'll log the power consumption with the same meter I used to log my dehumidifier so there won't be any calibration questions. If it works then I'll either buy it from you or return it, your choice. If it doesn't, I return it to you.
"Working" is defined as 50% or lower RH in that space at all times without raising the temperature above 70, conditions suitable for valuable book storage.
This should be an excellent testbed since even when the temperature is in the 90s in the day, it drops to at least the 60s at night. The common factor is the almost always high humidity.
You game?
John
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I do, as a registered US patent agent, having passed the same federal bar exam that attorneys take.

Yes...
Nick
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On 24 Apr 2007 15:48:24 -0400, snipped-for-privacy@ece.villanova.edu wrote:

So are you part of the problem?
How 'bout the rest of my comments? Can you claim that any of those patents are based on anything novel or unobvious? I mean, c'mon, a TREE SWING?

Should I take your snipping the rest of my post as an indication that you aren't interested in actually field testing the gadget you promote? With my proposal I don't see that you have anything at all to lose. Except maybe some face if it doesn't work.
John
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I never let myself get mad. I want peace. I tried to pinch his nostrils so he'd let go of my arm to breathe, but he shook his head, pulling me deeper into the cage.
I think it was then that he took out the first piece of my arm and swallowed it without breathing, because a terror of movement settled in me at that moment and lasted for months. He moved up the arm, and all the time those black, blank eyes evaluated me, like a shark's, calm and almost friendly. By this time, my right arm was a mangled mess of flesh, pushed-out gobs of fat, and flashes of bone two inches long, but my slow TV mind, watching, saw it as whole, just trapped in the hyena's mouth, in a tug-of-war like the one I used to play with my dogs--only it was my arm now instead of a sock. It didn't hurt. It never did.
The hyena looked up at me with those indescribable eyes and surged back again, nearly pulling me onto his face. I remembered self-defense class and the first lesson: "Poke the cockroach in the eyes." All the women had squealed, except me. "Ooooh, I could never do that." Ha, I'd thought, anyone who wants to kill me has no right to live. I'd poke him in the eyes...
I looked at those eyes with my fingers poised to jab. It was for my family and my friends that I stuck my fingers in his eyes. I just wanted to stop watching myself get eaten, either be dead and at peace or be gone, but other lives were connected to mine. I'm not sure if I did more than touch them gently before he let go and whipped past me to cower against the door to the outside, the Negev desert.
Events like this teach you yourself. We all think we know what we would do, hero or coward, strong or weak. I expected strength, and the memory of my tin-whistle scream curdles my blood, but I am proud of the stupid thing I did next. He cowered and whimpered and essentially apologized, still with those blank unmoving eyes, and I stood still for a second. My arm felt light and shrunken, as if half of it were gone, but I didn't look. From the corridor, I had a choice of two doors: the one through which I'd entered, leading back to the desert, and the one opening into the corral. I didn't think I could bend over him and unlatch the door to the desert. He'd just reach up and clamp onto my stomach. And I didn't want to open the door to the corral, or he'd drag me in and be able to attack the men if they ever came to help me. My body, still in control, made the good hand grab the bad elbow, and I beat him with my own arm, as if I had ripped it free to use as a club. "No!" I shouted. "No, no!" Lo lo lo, in Hebrew. I might even have said "Bad boy," but I hope not. It was the beating that damaged my hand permanently. I must have hit him hard enough to crush a ligament, because there is a lump on my hand to this day, five years later, but he didn't even blink. He came around behind me and grabbed my right leg, and again there was no pain--just the feeling that he and I were playing tug-of-war with my body--but I was afraid to pull too hard on the leg. He pulled the leg up, stretching me out in a line from the door, where I clung with the good hand to the mesh, like a dancer at the barre. It felt almost good, as if the whole thing were nearer to being over. In three moves I didn't feel, he took out most of the calf...
From Personal History: Hyena                  by Joanna Greenfield,                  in The New Yorker, Nov. 11, 1996

You might enjoy paying me to analyze them in excruciating detail :-)

Let's see... You wrote:

I don't think so. Putting aside your hyenalike behavior, it looks like this requires time and money on my part, with nothing to gain. Care to sweeten the pot? :-)
FWIW, it seems to me this might work well for you, with enough books and concrete and wood to absorb moisture in an airtight basement with a vapor barrier and no water leaks from the outdoors.
The average yearly temp in Chattanooga is 59.3 F, and 70 F air at 50% RH has w = 0.0079. The average outdoor humidity ratio is less than that from October through April. You could store lots of dryness in January, with a 37.4 F average outdoor temp and w = 0.0036. You are a bright boy. Look up the sorption isotherms for your materials and do your own estimates or simulations, s'il te plait. I gave you the concrete information.
Nick
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On 25 Apr 2007 05:21:32 -0400, snipped-for-privacy@ece.villanova.edu wrote:

Nah, don't think so. Even l'il ole me can tell that chasing a cat around with a laser pointer is neither novel, non-obvious nor lacking in prior art. Same with two ropes tossed over a tree limb and connected to a plank, what that tree swing patent consists of.

Oh, you have a lot to gain. You'd have confirmed data that the thing either works or doesn't in a humid climate like mine. At worst you'd end up with one of those units. At best you'd have confirmation data and zero dollars out of pocket. As an advocate of that product, surely you could get them to contribute a unit to the test.
Heck, I'll even submit a test plan in advance for your approval. Even though I have my preconceived notions about the efficacy of this gadget I AM interested in test results. My notions are wrong on very rare occasions, after all. And as always, I publish all raw data and my calculations. You can critique my analysis and/or do something different with the raw data.

Except that I live 100 miles away in the mountains above Tellico Plains. At 2500 feet in what amounts to an eastern jungle. I never appreciated what a jungle environment is like until I moved here. I stored my car and motorhome up here while I was on the road for about a year. When I came back the steering wheels were twice the normal diameters, encrusted with green mold. The pillows and bedlinens in the MH were green with mold. Even fingerprints were outlined in green mold! yeah, I know, my signature says Cleveland but that's just where my mail goes. We don't have mail service up here.
I had the power and thus the AC off for that period. The inside of the cabin was green too. What a clean-up job!
My basement had always been saturated with humidity and moldy but I didn't fully appreciate the conditions until I parked my vehicles here.
I'm open to letting the data regarding that fan gadget prove me wrong but I seriously doubt it will happen.
John
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I have no financial interest in this product. You might enjoy talking with them yourself.
Nick
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The Florida Solar Energy Center's first experimental report on two 10'x16' test structures, comparing conventional AC to the NightCool System is at:
http://www.fsec.ucf.edu/en/publications/pdf/FSEC-CR-1692-07.pdf
There's also a writeup of the system at
http://BuildItSolar.com .
Up to date daily data from the system is at:
http://infomonitors.com/ntc /
They will continue to evaluate it for the remainder of the year and add a dehumidification element to the system this summer using the intrinsic moisture capacitance of wood in the attic to dry out the building, which promises to reach dehumidification COPs of ~ 10--unheard of with conventional vapor compression equipment.
They may integrate PV to end up with an integrated solar electric and building cooling system all rolled into one.
Nick
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My post is definitely not on topic, but here goes anyway... Just for laughs :)
All patents are probably novel, as in original, new and unique, but to claim that they are always useful (or sane) is a stretch...
http://www.freepatentsonline.com/crazy.html
Start quote --
US Patent 6369603 - Animal Toy granted to Samuel Pai for a plastic stick. He was granted that in 1999. The genius is not that he invented a fake tree branch that you could throw for your dog, no. The true genius is that he noticed that no one had ever applied for a fake stick patent and then had the chutzpah to get it patented. Brilliant.
US Patent 3216423 - Apparatus for facilitating the birth of a child by centrifugal force.
-- end quote
/lm
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That's the law. The US patent office interprets "useful" in two ways: 1.) you have to convince an examiner the invention will actually work, as described (they are very skeptical of perpetual motion machines :-), and 2.) it can't be a weapon of mass destruction, eg an H-bomb.
They don't care if the invention is uneconomical or impractical or ugly, and so on. Some people get rich by filing such "submarine" patents well before technology makes them practical. A patent claiming techniques for for a vacuum-tube cellphone the size of a tractor-trailer might have been a gold mine if it didn't expire before ICs were invented.
Nick
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Neon John wrote:

I have to agree with you here. I have it from a (purported) relative of the patent holder for that, that he took out the patent specifically to prove how easy it is to get a patent that is _not_ novel. The US Patent Office has a history of issuing patents for practically anything and then letting the courts sort it out (see Michael Crichton's latest novel "Next" for the logical conclusions of that).

That actually sounds semi-reasonable (at least in a legal sense). The laser pointer was not previously patented as an exerciser of any sort. Clearly there's a novel application. So _somebody_ is entitled to patent it, but it would be hard to prove that the patent holder was the one who actually invented it's use for exercising (and blinding...) cats.
--
derek

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On Wed, 25 Apr 2007 11:06:32 -0300, Derek Broughton

It's certainly novel but it fails the non-obviousness test and the prior art test. Anyone who's played with light spots around animals knows that they'll chase the spot. IT doesn't have to be a laser. My cat and mom's dog will chase a flashlight spot.
In terms of prior art, a search of Usenet archives going far back before the patent was applied for will show discussions of chasing animals around with light spots. I know that I commented about how much fun it was to chase my cat around with a HeNe laser long before diode lasers hit the consumer market. Even before that there were talks about using flashlight beams.
Worse for this particular patent, as noted on the freepatentsonline crazy page, multiple prior patents had already been issued for the same thing. Just another application rubber-stamped.
It would be interesting to do an experiment to see just how silly an application has to get before it's rejected. I wish I had sufficient mad money to pay the fees, I'd give it a shot.
John
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I don't think this one is silly but I bet these guys got a patent on their new twin crank idea. http://thekneeslider.com/archives/2006/06/19/neander-turbo-diesel-motorcycle /
Go back 210 years and you find one Reverend Edward Cartwright made this little drawing. http://books.google.com/books?id=p8MJAAAAIAAJ&pg=PA64
___________ Andre' B.
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