DIY Dehumidifier

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Nick wrote: I measured a new efficient dehumidifier, which produced 1.6 kWh of heat
for every kWh consumed, ie 1 kWh from motors plus 0.6 kWh to condense about 2 pints of water, ie it consumed 0.5 kWh per pound of water, ie 5 cents/pint at 10 cents/kWh.
Nick,
How can a dehumidifier produce mor heat than the equivalent of the electricity it uses. A heat pump does that because it extracts heat from outside. A dehumidifier is usually self contained...the whole thing is all in the same space. All electricity consumed should be converted to heat. Even though it converts the water vapor to liquid water, the total heat is still there because it never left the room, only changed form.
Stretch
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It's an indoor heat pump that converts latent to sensible heat, with a COP of 1.6, in the case above.

Not always. The dehum above is 60% more efficient than electric resistance house heating in wintertime. Bill Shurcliff suggests air conditioning damp basements in wintertime. The AC might be mounted in a stairwell, with the hot coils in the living space.

It is, but beyond that, each pint of water condensed adds about 1000 Btu of sensible heat to the room air. Evaporating water requires heat energy. Condensing water releases heat energy.
Nick
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A properly controlled exhaust fan can dehumidify with 100X less energy than a dehumidifier.
Nick
Nick, that depends on the outside ambient. If it is very humid outside, running a fan will make it worse. What you say may be true in Massachusetts, but here in South Carolina, a residential exhaust fan does more harm than good about 8-9 months per year.
Stretch
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songofruth wrote:

Not clear why you think a dehumidifier is not the best solution.
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Matt wrote:

Mostly I've been keying in on the solution I suggested because my DH had a very strong preference for the Humidex unit. This would give him the same thing but at a (hopefully) greatly reduced out-of-pocket cost.
I do prefer a humidifier. Sure it adds bucks to the electricity bill but hey if that's the best solution, then that's the best solution. We have someone from our HVAC company coming out tomorrow with literature on ones that would connect to our HVAC system. (Since they service our machine one would think this could all be handled over the phone but noooo... they feel they must come out.) It looks like this solution too could run to near $1000.
I'm starting to think that I need to change my thread title (or start a new one) on how to figure out just how much dehumidifier I would need.
Take care, Melody
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Melody,
If you can tell us something about your location, the size and construction of your house, We might be able to give better advice.
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Melody,
I have written a few articles on humidity and mold issues that were published. Here are links to some of them.
Crawlspace problems: http://www.contractingbusiness.com/Classes/ArticleDraw/ArticleDraw.aspx?CIDr53&HBC=GlobalSearch&OAS=&NIL lse
We're in the mold business: http://www.contractingbusiness.com/Classes/ArticleDraw/ArticleDraw.aspx?CIDU56&HBC=GlobalSearch&OAS=&NIL lse
Humidity Control: http://www.contractingbusiness.com/Classes/ArticleDraw/ArticleDraw.aspx?CIDV43&HBC=GlobalSearch&OAS=&NIL lse
Stretch Kevin O'Neill
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songofruth wrote:

You seem to believe the outside air to be less humid than the inside air.
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Start going to a few garage sales and find a dehumidifier there. They are cheap enough and will solve the problem.
If it were winter and you had a humidity problem, i'd recommend looking for the source before searching for the temporary fix.
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