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Frugal Dehumidifier - any good models widely available?



 
 
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  #1  
Old April 23rd 07, 07:15 PM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
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Posts: 775
Default Frugal Dehumidifier - any good models widely available?

Joe wrote:

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...


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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  #2  
Old April 23rd 07, 07:31 PM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
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Default Frugal Dehumidifier - any good models widely available?


wrote in message
...

....

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.


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.






  #3  
Old April 23rd 07, 11:46 PM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
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Posts: 1
Default Frugal Dehumidifier - any good models widely available?

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...


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.

--
Bill McFadden http://www.rdrop.com/users/billmc
CAUTION: Don't look into laser beam with remaining eye.
  #4  
Old April 24th 07, 02:06 AM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
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Posts: 127
Default Frugal Dehumidifier - any good models widely available?

On 23 Apr 2007 14:15:55 -0400, wrote:

Joe wrote:

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...


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.


But that isn't what he asked about. If he has a serious humidity
problem as I did then venting won't do a thing. I tried (for about
$100 for a vent fan that fit in place of a concrete-block-sized vent).

Last year when I turned my vacation home into my residence and moved a
lot of possessions into my basement, I bought this dehumidifier:

http://www.samsclub.com/shopping/nav...95&prDeTab=2#A

Which is this unit, private labeled for Sam's I think:

http://products.geappliances.com/App...=GEA &TABID=2

Same specs, same control panel, same looks.

Later I connected a watt-hour meter to the unit. With the humidistat
set for 50% RH, from the period from 11/04/06 til today, the unit has
consumed 346 KWH or 2.03 per day. At my power rate that's 13 cents a
day, $3.95 per month.

My basement is quite moist - green mold grew everywhere - but quite
cool, never going above 60 deg even in the summer. That, of course
has a very favorable impact on the cost of operating this unit.

The way to evaluate the efficiency of a dehumidifier is its rating in
pints removed per KWH consumed. Using the spec sheet of 580 watts
draw and 40 pints/day, that works out to 2.9 Pts/KWH.

It turns out that this is worst-case, for I just checked my unit with
a Kill-A-Watt and measured 450 watts. That makes the Pts/KWH a much
better 3.7. That compares nicely with the 5.3 that the Santa Fe unit
that Bill posted about in this thread. The GE is far cheaper (list
price is $189). At the energy consumption rate that mine is
exhibiting I could never save enough energy to pay the cost difference
for the Santa Fe.

One other thing to note. For low temperature and/or very low humidity
operations, your dehumidifier must operate in the freezing mode. That
is, the evaporator must get cold enough to form frost to condense
sufficient moisture to achieve a low humidity and the unit must have a
good auto-defrost cycle. The GE does both.

For higher temperature operation and moderate humidity reduction, a
modified window AC works great. The modification involves stopping up
the passage from the evaporator to the condenser that lets the
condensate be slung upon the condenser and evaporated. Block the tube
and drill a hole in the bottom to allow the condensate to drain out.

At under a hundred bux for a 5KBTU window unit, that's a heck of a
good deal. Just sit it in the floor over a drain or bucket and turn
it on. If the room is small enough that the humidity is reduced
rapidly then you might need an external humidistat.

I used one like that in the upstairs part of my home for several
years. I haven't measured the efficiency in terms of Pts/KWH but I
know that my power bill is about the same so the AC can't be a big
power hog.

John
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
All great things are simple and many can be expressed in single words:
Freedom, Justice, Honor, Duty, Mercy, Hope. -Churchill
  #5  
Old April 24th 07, 06:00 AM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
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Posts: 775
Default Frugal Dehumidifier - any good models widely available?

Neon John wrote:

wrote:

Joe wrote:

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...


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.


But that isn't what he asked about. If he has a serious humidity
problem as I did then venting won't do a thing.


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."

Last year when I turned my vacation home into my residence and moved a
lot of possessions into my basement, I bought this dehumidifier:

http://www.samsclub.com/shopping/nav...95&prDeTab=2#A

The way to evaluate the efficiency of a dehumidifier is its rating in
pints removed per KWH consumed. Using the spec sheet of 580 watts
draw and 40 pints/day, that works out to 2.9 Pts/KWH.

It turns out that this is worst-case, for I just checked my unit with
a Kill-A-Watt and measured 450 watts. That makes the Pts/KWH a much
better 3.7...


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

  #6  
Old April 24th 07, 08:03 AM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
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Posts: 127
Default Frugal Dehumidifier - any good models widely available?

On 24 Apr 2007 01:00:42 -0400, wrote:

Neon John wrote:

wrote:

Joe wrote:

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...

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.


But that isn't what he asked about. If he has a serious humidity
problem as I did then venting won't do a thing.


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%.


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.


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."


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



Last year when I turned my vacation home into my residence and moved a
lot of possessions into my basement, I bought this dehumidifier:

http://www.samsclub.com/shopping/nav...95&prDeTab=2#A

The way to evaluate the efficiency of a dehumidifier is its rating in
pints removed per KWH consumed. Using the spec sheet of 580 watts
draw and 40 pints/day, that works out to 2.9 Pts/KWH.

It turns out that this is worst-case, for I just checked my unit with
a Kill-A-Watt and measured 450 watts. That makes the Pts/KWH a much
better 3.7...


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.


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.

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.


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
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
All great things are simple and many can be expressed in single words:
Freedom, Justice, Honor, Duty, Mercy, Hope. -Churchill
  #7  
Old April 24th 07, 11:41 AM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
external usenet poster
 
Posts: 775
Default Frugal Dehumidifier - any good models widely available?

Neon John wrote:

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%.


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.


Sounds like you have enough concrete, but few dry days... 500 pints
is only 10 days at 50 pints per day.

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.


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

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."


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


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.

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.


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


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

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...


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, OTOH, have many "95-95" days - 95 degrees and 95% humidity.


We have a few nights like that in August.

Your overpriced hair dryer blower won't touch that.


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

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.


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.


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

None of this addresses a moisture problem in a basement, of course.


Of course it does, precisely.

I don't understand your abnormal advocacy of that little fan. Do you
have a financial interest in the product?


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

  #8  
Old April 24th 07, 08:20 PM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
external usenet poster
 
Posts: 127
Default Frugal Dehumidifier - any good models widely available?

On 24 Apr 2007 06:41:25 -0400, wrote:



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


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.


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?

None of this addresses a moisture problem in a basement, of course.


Of course it does, precisely.


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
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
All great things are simple and many can be expressed in single words:
Freedom, Justice, Honor, Duty, Mercy, Hope. -Churchill
  #9  
Old April 24th 07, 08:48 PM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
external usenet poster
 
Posts: 775
Default Frugal Dehumidifier - any good models widely available?

Neon John wrote:

By law (US Code 102/103), the patent would not have been
issued if it were not novel.


... if you believe that, I have some nice oceanfront land in TN to sell you...


I do, as a registered US patent agent, having passed the same federal
bar exam that attorneys take.

None of this addresses a moisture problem in a basement, of course.


Of course it does, precisely.


Really?


Yes...

Nick

  #10  
Old April 24th 07, 09:06 PM posted to misc.consumers.frugal-living,alt.home.repair,alt.energy.renewable,alt.energy.homepower
LM
external usenet poster
 
Posts: 1
Default Frugal Dehumidifier - any good models widely available?


On 24 Apr 2007 06:41:25 -0400, wrote:


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.


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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