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boaterbob
Premium
join:2005-08-01
Moncks Corner, SC

50 or 70 pint dehumidifier

I plan on buying a Frigidaire FAD704DUD 70 Pt. Dehumidifier. As the unit will have the drain hose connected to an external drain - so I don't need to empty the water reservoir tray, does it matter if I buy a 50 pt unit or a 70 pt unit? Both will simply drain to the outside so I'm not concerned with the 'bucket' filling up and needing to be emptied. Obviously the 50 pt unit will cost less and they seem to be the same otherwise.

Thanks


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
The pint size is the amount of work it can do in a given amount of time, not how big the holding tank is. The 70 pint model can pull 20 pints more out of the air in a 24 hour period than the 50 model.

golfer55

join:2009-12-25
Grottoes, VA
reply to boaterbob
since you will be draining it with a hose save some $$$ and get the smaller capacity one

boaterbob
Premium
join:2005-08-01
Moncks Corner, SC
Just found this answer at Frigidaire Web site:
The capacity of the dehumidifier unit refers to the amount of moisture the unit can remove from the air in a 24-hour period. For example, a 30 pint dehumidifier will remove up to 30 pints of moisture from the air in a 24-hour period, until the desired humidity level in the room is reached and if the bucket is emptied regularly.

So, I should have checked first

iknow
Premium
join:2012-03-25
said by boaterbob:

Just found this answer at Frigidaire Web site:
The capacity of the dehumidifier unit refers to the amount of moisture the unit can remove from the air in a 24-hour period. For example, a 30 pint dehumidifier will remove up to 30 pints of moisture from the air in a 24-hour period, until the desired humidity level in the room is reached and if the bucket is emptied regularly.

So, I should have checked first

unless you want to use it for the winter, a small window AC is better, it operates the same as a dehumidifier except you have the hot air from the condensor going outside instead of heating up the house.


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
Most dehumidifiers pass the air first over the evaporator, then over the condenser. They shouldn't change the temperature of the space significantly. Plus many spaces, like a basement, are not well suited for installation of a window unit. And the space gets very cold as it runs so much to remove the humidity.

iknow
Premium
join:2012-03-25
said by Lurch77:

Most dehumidifiers pass the air first over the evaporator, then over the condenser. They shouldn't change the temperature of the space significantly. Plus many spaces, like a basement, are not well suited for installation of a window unit. And the space gets very cold as it runs so much to remove the humidity.

you'd think they would not change the temperature significantly by design, but every one i've used makes it hot as hell in the room it's in. also, in the summer, it gets too hot in my basement for comfort, so an AC cools and removes the humidity there, makes it quite dry actually, without being too cold. this does depend on a particular situation, but it seems a waste to use a dehumidifier, then the AC has to remove that heat.

Bob4
Account deleted

join:2012-07-22
New Jersey
reply to Lurch77
The FAD704DUD is spec'ed at 765 Watts. That heat goes into the house (and if you have central A/C, will need to be removed by the cantral A/C). So that's like having ten 75 Watt light bulbs running in your basement all the time.

iknow
Premium
join:2012-03-25
said by Bob4:

The FAD704DUD is spec'ed at 765 Watts. That heat goes into the house (and if you have central A/C, will need to be removed by the cantral A/C). So that's like having ten 75 Watt light bulbs running in your basement all the time.

my 8000 BTU AC only draws 816 WATTS and it cools the air.


norbert26
Premium
join:2010-08-10
Warwick, RI
reply to iknow
said by iknow:

said by Lurch77:

Most dehumidifiers pass the air first over the evaporator, then over the condenser. They shouldn't change the temperature of the space significantly. Plus many spaces, like a basement, are not well suited for installation of a window unit. And the space gets very cold as it runs so much to remove the humidity.

you'd think they would not change the temperature significantly by design, but every one i've used makes it hot as hell in the room it's in. also, in the summer, it gets too hot in my basement for comfort, so an AC cools and removes the humidity there, makes it quite dry actually, without being too cold. this does depend on a particular situation, but it seems a waste to use a dehumidifier, then the AC has to remove that heat.

i have found this to be true the dehumidifier will output heat. But there is a mystery i can't solve . Years ago in the house i grew up in there was an old sears coldspot or kennmore . There was no AC anywhere in the house. When the humidity hit the dehumidifier was run. During a heatwave since there was no AC in the house the finished basement was the retreat. With the dehumidifier running that basement never got hot and either did i feel any hot air coming out of it. This took in air through the front panel where there were louvers. The air blew out the back. At the bottom in the rear was the condensate pan you emptied (there was a hose provision but the drain pan was used) It collected condensate fine. For the life of me i can't figure out WHAT was different about that made in USA dehumidifier VS the dehumidifier on the market imported from china today. In theory a dehumidifier is a dehumidifier and should work the same now as it did then.


tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
kudos:9
Reviews:
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I assume that was due to size and efficiency. The electrical energy consumed by the dehumidifier will heat the space. How much depends on: how much energy is consumed by the dehumidifier, how large the room is, and are they sinks/sources of heat. In a basement ground temperature is usually lower then air so added heat will flow through the walls into the surrounding soil.

We have a unit in our basement and while the heat is noticeable while it is running on balance the lower humidity improves comfort. Unfortunately our basement is fairly well connected to the 1st floor so humidity levels are greatly influenced by weather conditions.

/tom

Zach1
Premium
join:2006-11-26
NW Minnesota
reply to norbert26
My guess is that newer units remove considerably more humidity than those made a couple of generations ago. The process of converting water vapor to a liquid state releases heat. This heat energy as well as the heat generated due to inefficiencies in the unit itself are released into the room.

Water vapor will only condense onto another surface when that surface is cooler than the dew point temperature, or when the water vapor equilibrium in air has been exceeded. When water vapor condenses onto a surface, a net warming occurs on that surface. The water molecule brings heat energy with it.

»en.wikipedia.org/wiki/Water_vapor

The enthalpy of condensation (or heat of condensation) is by definition equal to the enthalpy of vaporization with the opposite sign: enthalpy changes of vaporization are always positive (heat is absorbed by the substance), whereas enthalpy changes of condensation are always negative (heat is released by the substance).

»en.wikipedia.org/wiki/Enthalpy_o···rization

For even more exciting reading......

»en.wikipedia.org/wiki/Latent_heat
--
Zach


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
I live it everyday. And it is still extremely boring to read.


norbert26
Premium
join:2010-08-10
Warwick, RI
reply to Zach1
Well mystery solved. That dehumidifier from years ago must have been low power. The house only had 60 AMP service and the condensate pan was not that large. Fast forward to the present. A year and a half ago i bought a dehumidifier to boost / assist an AC in an adjoining room . The room i placed the dehumidifier in has those sliding windows that are a PITA to mount a window shaker in. I put the AC window shaker in the adjoining room and it cools both rooms. Sometimes if humidity is extreme (like during the night) the AC will cool but it may get humid in the other room. I set the dehumidifier at 60% so it wont run too long and not get too hot. I made the mistake of the dehumidifier being over sized at 70 pints . Now i know i needed it smaller but whats done is done now i will live with it. All this said they have combo AC / dehumidifiers on the market. These have a big heat exhaust hose you can run to a window and exhaust the heat to the outside. If its damp / cool you can run it as a standard dehumidifier. This would address the issue of heat build up. The ones i have seen do about 12,000 BTUs but this will work where you can't install a window shaker.


ArgMeMatey

join:2001-08-09
Milwaukee, WI
kudos:2
Reviews:
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reply to boaterbob
I used to have some computer labs where we put in window A/C in basement rooms and people complained they were always too cold, so they would shut off the A/C and the humidity would go tropical. There was condensation on the walls. We'd then have mold problems.

Seems to me the earlier post made sense: Basement walls, typically block or concrete, are heat sinks, dissipating heat into the soil. It wasn't necessary to remove heat from those rooms.

When we put dehumidifiers in, those same basement rooms were very comfortable, even though the temp was much warmer than when we had A/C.
--
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16TDN2870
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Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
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said by ArgMeMatey:

I used to have some computer labs where we put in window A/C in basement rooms and people complained they were always too cold, so they would shut off the A/C and the humidity would go tropical. There was condensation on the walls. We'd then have mold problems.

Seems to me the earlier post made sense: Basement walls, typically block or concrete, are heat sinks, dissipating heat into the soil. It wasn't necessary to remove heat from those rooms.

When we put dehumidifiers in, those same basement rooms were very comfortable, even though the temp was much warmer than when we had A/C.

As humidity increases with a given temperature the "feel" to people is warmer.

We dehumidify in summer.....

As humidity decreases with the same given temperature the "feel" is colder.

So putting in dehumidifiers which should have lowered the humidity the workers should have felt colder if the temperature was kept the same.

We humidify in winter......


CylonRed
Premium,MVM
join:2000-07-06
Bloom County
reply to Lurch77
said by Lurch77:

Most dehumidifiers pass the air first over the evaporator, then over the condenser. They shouldn't change the temperature of the space significantly.

Not for any that I have had and I have had to run dehumidifiers for the last 5+ years in a specific room (main room - not basement) and the temps are up by 5-7 degrees easy.
--
Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
said by CylonRed:

said by Lurch77:

Most dehumidifiers pass the air first over the evaporator, then over the condenser. They shouldn't change the temperature of the space significantly.

Not for any that I have had and I have had to run dehumidifiers for the last 5+ years in a specific room (main room - not basement) and the temps are up by 5-7 degrees easy.

All you have to do is put your hand in the discharge air from the condenser to see it's warmer than room temperature which means it's warming the space.


Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4
I did say significantly. We have one that runs in our crawlspace. It's not hot down there.


cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to boaterbob
The amount of heat released depends on the amount of humidity converted into water.
Water vapors contain a huge amount of energy. Condensing 70 pints of water will release some 70,000BTU of heat. That's the output of your typical 1500W space heater running for 14hrs... and it's before even thinking about the heat produced by the unit itself...


cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to Lurch77
said by Lurch77:

I did say significantly. We have one that runs in our crawlspace. It's not hot down there.

The crawl space is a big heat sink.

iknow
Premium
join:2012-03-25
reply to ArgMeMatey
said by ArgMeMatey:

I used to have some computer labs where we put in window A/C in basement rooms and people complained they were always too cold, so they would shut off the A/C and the humidity would go tropical. There was condensation on the walls. We'd then have mold problems.

Seems to me the earlier post made sense: Basement walls, typically block or concrete, are heat sinks, dissipating heat into the soil. It wasn't necessary to remove heat from those rooms.

When we put dehumidifiers in, those same basement rooms were very comfortable, even though the temp was much warmer than when we had A/C.

a portable a/c with part of the condenser air discharge going back in the room is the perfect answer. if it gets too hot, all of the air from the condenser can be routed outside!. i'm sorry to hear you lost your computer labs, BTW.


ArgMeMatey

join:2001-08-09
Milwaukee, WI
kudos:2
Reviews:
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said by iknow:

a portable a/c with part of the condenser air discharge going back in the room is the perfect answer. if it gets too hot, all of the air from the condenser can be routed outside!. i'm sorry to hear you lost your computer labs, BTW.

Are you talking custom sheet metal with pneumatics, or a unit manufactured to do that?

These were casement A/C units and we had scores of them warehoused, doing nothing.

Semantics, yeah, I should have said "managed" instead of "have".
--
USNG:
16TDN2870
Find your USNG coordinates:
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iknow
Premium
join:2012-03-25
said by ArgMeMatey:

said by iknow:

a portable a/c with part of the condenser air discharge going back in the room is the perfect answer. if it gets too hot, all of the air from the condenser can be routed outside!. i'm sorry to hear you lost your computer labs, BTW.

Are you talking custom sheet metal with pneumatics, or a unit manufactured to do that?

These were casement A/C units and we had scores of them warehoused, doing nothing.

Semantics, yeah, I should have said "managed" instead of "have".

a satisfactory setting probably could have been set by a manual lever, basements have a mostly constant ground temperature. electronic equipment, including computers, are more sensitive to temperature, rather than humidity, within reason.

itguy05

join:2005-06-17
Carlisle, PA
said by iknow See Profileelectronic equipment, including computers, are more sensitive to temperature, rather than humidity, within reason. [/BQUOTE :

Any more as log as you are comfortable the computer will be fine. Most will run forever at temps as high as 90 degrees or so. The fans may run faster and it may theoretically reduce life but it's the difference between 10 years and 9.975 years.



cowboyro
Premium
join:2000-10-11
Shelton, CT
said by itguy05:

said by iknow:

electronic equipment, including computers, are more sensitive to temperature, rather than humidity, within reason.

Any more as log as you are comfortable the computer will be fine. Most will run forever at temps as high as 90 degrees or so. The fans may run faster and it may theoretically reduce life but it's the difference between 10 years and 9.975 years.

A temperature increase of 10 degrees (C) cuts the life of capacitors in half.


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
said by cowboyro:

said by itguy05:

said by iknow:

electronic equipment, including computers, are more sensitive to temperature, rather than humidity, within reason.

Any more as log as you are comfortable the computer will be fine. Most will run forever at temps as high as 90 degrees or so. The fans may run faster and it may theoretically reduce life but it's the difference between 10 years and 9.975 years.

A temperature increase of 10 degrees (C) cuts the life of capacitors in half.

We had PLC's and other electronic instrumentation operating in the field at 135+ degrees F. No difference in failures compared to those operating in lower temperature areas.


cowboyro
Premium
join:2000-10-11
Shelton, CT
said by Jack_in_VA:

We had PLC's and other electronic instrumentation operating in the field at 135+ degrees F. No difference in failures compared to those operating in lower temperature areas.

Home electronics are not designed for industrial temperature ranges.


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
said by cowboyro:

said by Jack_in_VA:

We had PLC's and other electronic instrumentation operating in the field at 135+ degrees F. No difference in failures compared to those operating in lower temperature areas.

Home electronics are not designed for industrial temperature ranges.

Really? and this blanket statement is coming from an electronics expert? I think I might know a little about this also since I've been in the field since 1964. Additionally we had Computers right out in the heat, dust and dirt. Yes the same ones you and I have in our "HOMES". We would open them up every so often and blow them out.


cowboyro
Premium
join:2000-10-11
Shelton, CT
said by Jack_in_VA:

I think I might know a little about this also since I've been in the field since 1964.

So you are denying the fact that the life of electrolytic capacitors is greatly reduced by an increase in operating temperature? WOW.. just wow...