Possible mold or other HVAC related issue?

Hi all! Not sure if this should be in the HVAC section as it is mostly related to building comfort but not directly to a HVAC equipment...

Anyways, my uncle has been living in the same house since he purchased it in early '73. Since then, he never had any problems in the house (so he says) and apparently the moisture (RH) has always been in the 40-60% during winter, and possibly a bit higher during summers where he normally has to run the dehumidifier in the basement.

Same applies for last summer, he ran his dehumidifier all day long in his basement to keep the humidity to a decent (healthy and comfortable) level (around 55%). He said he was removing about 5 gallons of water a day, that seems a bit much to me but he confirmed this is what his dehumidifier's tank capacity was..

Now, its the opposite. The RH stays around 20-25% and nothing will make it increase.. We tried to run the humidifier for hours, the RH goes to 40-45, then about half hour later after we shut the machine down, goes back down to 20-25%. The air feels really dry and we all have problems breathing. Our throats feel like it gets infected like when you are about to get a cold (itchy, runny nose, etc..). He is convinced that there is mold in his house. Could it be mold causing the RH issue and the breathing problems? One after the other, all the family members started to feel the effects of that strange phenomenon...

I repeatedly mentioned that as far as I am concerned (and know), mold doesn't grow at such low RH levels. I do believe the "breathing" problems and cold-like symptoms are due to the excessively low RH. What can "suck" the moisture out that fast and consistently???

We have been searching for mold signs, no strange odors, nothing looks blackened.. Since last spring, he has developed some kind of tongue thrush his doctor is baffled about where it comes from..

Has anyone ever heard or experienced such scenario??? Any help is appreciated, my uncle and aunt will be more than happy if I bring them some interesting piece of info..

As usual, thanks to all!!

In what part of the country does your uncle live? What type of heating unit, gas or electric? Has the unit been serviced? Is the humidifer attached to the furnace or a stand alone one? Does the basement have finished walls/insulation?

Beats me.

Try
[ame]http://www.google.com/search?client=safari&rls=en&q=%22causes+of+low+humidity%22&ie=UTF-8&oe=UTF-8[/ame]

Different keywords may get you more hits but these five may be all you need.

Older people need the heat set higher because they lose the layer of insulating fat under their skin. Maybe this 'stat setting increase was so gradual since '73 that nobody noticed it.

Hey guys! thanks for the replies!! I am still collecting info regarding this issue and its baffling me as well...

The house is located in Montreal, Quebec (Canada). It has only electric baseboards and there are 2 of them in the basement. The uncle said the heating system has been sufficiently keeping the place warm all that time since '73..

The humidifier is a stand alone unit. The basement is fully finished with walls and sheetrock ceilings..

The two things I am thinking about is a crack he mentioned in the foundations. The crack has been patched with epoxy compound a few years back. Could water be seeping thru even during winter and cause mold/spores? At such low RH levels, I highly doubt..

Another thing is an old water spill from the washer upstairs. The leak happened a few years back, noting happened in between..

Wuzzat?, I tried to google this issue numerous times. I have found nothing so far... There are tons of forums, websites and other references mentioning and discussing how to reduce RH but not to INCREASE it....

I was thinking about that: Could Radon lower HR??

Maybe the characteristics of your aquifer have changed

http://www.google.com/imgres?imgurl...=8vMKUbuUCMjn0gHv8oBA&ved=0CEsQ9QEwAw&dur=162

and with it, the water table?

hmmm wow! I dont know what to say... you suggest some kind of climate change could have caused this? Sure thing, the insulation isnt getting better after 40 years... And our climate has changed quite a bit. Whats baffling me is the fact that something draws the humidity out of the house really fast... How can outside be 55-60% and inside 20-25% when the heating is not really so strong in the house (19-20C) ?

Changes in climent or higher water table should not make any difference inside at least for my thinking anyway.
I would consider the age of the building, systems get old and break down.
First I would have the pros in to take an air quality test. You could have all kinds of problems but first you want to know just how healthy the invirement is.
You mentioned a water leak a few years ago. If mold started to grow and then stopped, there still may be spores flooting around.
After that you want to consider the age of the perimter drain and the waterproofing on the foundation.
And then think about a miner plumbing leak or small roof leak, either of which could be feeding small amounts of water into places that just don't show up in the living space.

Aquifers and water tables are affected by many activities of people, but I think not so much climate change.
Have your neighbors reported similar symptoms?

As far as temps and humidity, a psychrometric chart may be able to tell you what else must be going on for this to happen, but using one is a bear.

If this gets solved we're all going to learn a lot.

I went to the uncle's place yesterday and we opened a few walls... I took some pics. AFAIK, there are some minor signs of mold in the garage (against an outside wall he used to pile crap against for 15 years +) and *maybe* underneath the plywood floor in the basement. He is insisting for the mold scenario. Whatever is going on in that house, its either all imaginary (I stayed all day yesterday and did not feel anything nor I showed symptoms of any kind) and I have asthma and allergies or its serious and I am an exception... Again, I am no expert in mold so I am not sure. I highly recommended to contact an expert to inspect and test the house if he is so convinced that there is mold crawling in the walls...

I am not convinced but maybe I am wrong...

On the other side, neighbors have confirmed RH levels below 25% in their house, and apparently as low as 10% in their garages... I too doubt but I believe it may be in the 20-35% zone.

First picture shows a chunk of the garage wall we opened just by a stud. The stud appears to be fairly well preserved and the drywall we removed showed slight traces of past water leakage or humidity but no black mold. (THe white stuff behind the gray baseboard are styrofoam particles from opening the wall)

The second picture shows a closer view of the opening. I myself cannot see anything harmful. Can you?

Third pic shows is the interesting one.. (NOTE its upside down for whatever reason)... Its looking underneath a basement wall (the baseboard is on the upper portion of the picture). YOu can see the concrete fromt he foundations is somehow blackened. Is it mold? I also noticed on the baseboard some small traces of mold as well (the black spots). When we opened the floor to look under it, I made the mistake of sticking my face in the hole and smelling... I kinda had a musky / old basement odor coming to my nose but nothing else...

Anyways, if anyone has something to do, Im all hearing!

I would have the air tested, you could be doing alot of dammage for no gain. I don't see anything to get exited about. But dry basements don't have that " musty basement smell"