Why is high humidity bad?

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  #1  
Old 12-16-15, 09:48 AM
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Why is high humidity bad?

High guys.. I got high humidity in my 2nd unit.. it's like 80% in there.. and I do see water on the window edges to prove it?

so I think if I buy a dehumidifer and get a hose.. it will create heat in there it's only 50F right now.. and um based on running one before.. I know it will suck up all that water as it also heats up the space.. and I know lowing the humidity is good for things like mold.. but I still don't see why you have to spend the money/ELECTRICITY..

Can you convince me.. cause ahh I still don't see why??

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These are the current readings of my 2nd unit.. and my unit.. mines the bottom one..
 

Last edited by PJmax; 12-16-15 at 05:29 PM. Reason: reoriented pic
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Old 12-16-15, 11:25 AM
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Black mold is a pretty good reason. I'd try to keep it under 50%. Mold remediation is very expensive.
 
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Old 12-16-15, 12:38 PM
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What do you mean by "2nd unit"? Your picture is of an indoor/outdoor thermostat and it's the outside that's showing 80% humidity. Either your thermometer is quite inaccurate or you've got 60% humidity inside.

You mentioned two of the reasons to keep the humidity down in your post. Condensation and mold. How much you need to run a dehumidifier will depend on how the moisture is getting into your "2nd unit". If the area is well sealed you may not need to run the dehumidifier much once you initially get the moisture out. If you've got an unsealed concrete slab or other ways for water vapor to get inside then you'll need to run the dehumidifier more. I have one in a storage room in my house and it seems to run less than 10% to keep the humidity down where I want it.
 
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Old 12-16-15, 01:31 PM
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Musty smell in the room.
Going to take a toll on the woodwork around those windows.
One of the main causes fornt paint to fail.
Get bad enough it can lessen the the R value of the insulation.

Lots of things can cause it to be to high.
Running a non vented propane heater or fireplace.
Bathroom range hood or dryer vent not ran to the outside.
Not running the bathroom vent long enough after shower, or worst yet not having one.
If there's a dirt floor in a crawlspace not having a vapor barrier on the ground.
Improper roof venting.
 
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Old 12-16-15, 04:35 PM
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What do you mean by "2nd unit"? Your picture is of an indoor/outdoor thermostat and it's the outside that's showing 80% humidity
the humidity is 80% just cause a temperature sensor is labeled "outside" doesn't mean you have to put it out there.. it's in my 2nd unit as I said.. at 80% 'ish..

I have a duplex if that helps.. 2 living units.. but 1 house/building.

Musty smell in the room.
Going to take a toll on the woodwork around those windows.
One of the main causes fornt paint to fail.
Get bad enough it can lessen the the R value of the insulation.

Lots of things can cause it to be to high.
Running a non vented propane heater or fireplace.
Bathroom range hood or dryer vent not ran to the outside.
Not running the bathroom vent long enough after shower, or worst yet not having one.
If there's a dirt floor in a crawlspace not having a vapor barrier on the ground.
Improper roof venting.
Okay that sounds like good advice..

"Running a non vented propane heater or fireplace." no don't have that..

"Bathroom range hood or dryer vent not ran to the outside." okay I don't have the bathroom vent.. I do have a window.. but I don't think it's ever opened on that side..

Currently the unit is empty.. and ahh I'm not expecting people anytime soon.. but there have been people in it taking showers which based on what your saying has "created" the humidity.

If there's a dirt floor in a crawlspace not having a vapor barrier on the ground.
hmm.. not sure what that is? (vapor barrier) or why that matters?

At least the humidity #'s are a little better on my side.. which am venting (window) at times.. and heating and living..

yah but I don't see any black mold.. I see condensation on the windows.. I read "high" on the temperature sensor.. but I still think 50 degrees has got to be cold for e'm ehh?
 
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Old 12-17-15, 02:52 AM
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A problem I see is definitely people taking showers without having a good exhaust fan.
A window will not work because you likely will not keep it open long enough to reduce the humidity.
A bigger problem could be the low temperature you are keeping this space at.
The fact is that "relative humidity" is just that, humidity % relative to the space temperature.

If you were to raise the temperature in the home the relative humidity % would go down with no change to the actual moisture content.
The other issue with running the space at low temps is the window surface temperature will be also low enough to condense the moisture that is in the air.

You need to change something.......first ventilate the space to remove the humidity, either stop having showers or install a proper exhaust fan that is run long enough to lower humidity and raise the temperature to reduce the window's ability to condense what humidity is in the air.
 
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Old 12-17-15, 04:00 AM
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When I lived in fla about the only way to reduce the humidity in a home without a dehumidifier was to run the HVAC regularly. I suspect running a dehumidifier would be cheaper than raising thermostat.

Another issue not mentioned [unless I missed it] is high humidity can make doors swell where they won't open and close properly.
 
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Old 12-24-15, 09:38 PM
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I have reduced the humidity to 50% ish right now.. which did remove tons of moisture on the windows that seemed to get real bad (aka whole window area wet with water)

I'm attempting to reduce the humidity to 30% now.. but I do not understand what creates it????

How can a home that's not lived in.. be at 50% humidity and seems like it's rising??? in the middle of winter..

I know that's it's possible there is some kind of leak.. because weirdly one day.. someone noticed all sorts of water coming down the walls.. but it only occurred at a very bad rain storm it has yet to repeat... (the effect/leak) but if you touch the walls that were affected even now.. there dry.. so it's possible it's the leak??

Or that sub-flooring thing.. on my side of the duplex.. humidity is mostly normal.. but it does seem like I have to run that dehumidifer which "creates" heat doing it's job..

---

Hmm.. okay I watched this video and I feel a little more educated now.. so I stopped trying for 30% and will now hold at 50% I checked my whole unit for water spots and black mold.. didn't find any other then a bunch of mold that had already grown through my house during other "humidity" factors-times.. that just needs to be wiped off/cleaned what have you..

I see now I need a permeant humidifier to get this in check.. I need to find one I can throw in the sink so it can "drain" instantly because it's ridiculous to have to drain these.. as I often mind my full after 3-4 days.. something like that.. I think it probably holds 3 gallons?
 

Last edited by theemaster; 12-24-15 at 10:30 PM.
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Old 12-25-15, 05:08 AM
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There are dehumidifiers that have a built in pump. You connect a hose to them and can run the hose to a sink, floor drain or outside underneath a door. Mine is located very far from any drain so I have about 30' of hose take the condensate to the sump for my furnace/AC which pumps it the rest of the way out of the house.
 
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