Dehumidification in hot, humid weather
 

Roof leak led to tarp on roof, which is causing extreme humidity upstairs (windows fogged over). Turned on air conditions upstairs to get rid of heat and humidity. Result:

1. More condensation on outside of window
2. Mold all around the window frame around the air conditioner
3. Humidity and small mold specks inside the double-paned window
4. Extensive mold on the frame around the inside of the window

I've washed all the visible mold except for the inside of the window. I replaced the two-year-old air conditioner because it smelled like mold. I realize I need to get the window glass replaced.

What I can't figure out is why the air conditioning seems to be worsening the humidity problem around the unit. I think the combination of hot, humid summer, the roof tarp, and poor attic ventilation is the problem. I will have roof vents installed when the roof is replaced. There are soffit vents and gable vents, but the gable vents are too small.

In the meantime, what can I do to reduce the humidity upstairs and avoid more mold? Pretty worried about the health impacts at this point.

Thanks!

In Summer months we run a dehumidifier 24/7 and it makes the inside much more comfortable than the air conditioner alone would. Our dehumidifier removes several gallons of water from the air daily. It seems likely that a dehumidifier would help remedy your problems.

^ This.

Sent from my SM-G950U using Tapatalk

Regarding the hot attic...

If you have gable vents on opposite ends of the attic you may be able to install a power vent that brings air across from one to the other.

This might help you soon.

Hi Sailin'

Bummer of a situation. I agree on the dehumidifier. Try to find one that has a built in pump that you can run to a drain. They were on Amazon a couple of years ago if you cant find one locally.

I understand your desire to rid yourself of mold, and I'm sure there is some stuff you should throw away. But I do not understand the need to replace the glass. You should be able to clean and completely disinfect a glass surface--laboratories do this every day. Soap and water, alcohol, bleach--each of these will kill just about anything.

It is the porous surfaces, such as wood and drywall, that are challenging. On the porous surfaces, you might investigate anti-mildew paint.

Not Actually Seeing It, But...
 

I think you are wise to worry about health impacts: Household mold has recently been implicated in a nerve condition known as peripheral neuropathy. (Usually a tingling that starts in the foot and lower leg—pain and burning are common complaints).

My guess is that your interior roof area, wood structure, insulation, and any affected stored materials are soaked with water. This weather isn't improving a speedy dry-out. By now, the tarp may be compromised also. As condensation also collects under the tarp, rolling the tarp back during sunny days should be helpful.

I'd direct several 18-inch "box" fans to draw the moisture from the wood, and keep the house fully open on sunny days. Direct one fan at the affected window.

When I used a dehumidifier, it was placed in the bathtub with the little plastic box removed—the box that was designed to collect the condensate. It ran for several weeks, and did the job. The dehumidifier's effect is similar to an air-conditioner, but more economical in operation.

I'd still run the A/C, but remove the filter. The filter (only) is probably what has produced the mold odor.

She's stating that the mold is between the panes.
Fogging between the panes.
That would be a failed seal on the unit.

For the rest, no bleach. It destroys would fibers. Plenty of newer products, and for surfaces to be painted... mold-killing primer.

You can find Moldex or Mold Control at most outlets, and most should carry some mold-killing primer.

I discovered a small crack in one corner of the pane so yes, the seal has failed. According to my reading, vinegar effectively kills mold, better than bleach.

So you run the air conditioner and the dehumidifier at the same time, correct?

I have another idea: There's a small door to the attic in the upstairs ceiling, about 24" x 24". I could open that door so maybe the AC and a dehumidifier might cool and dry the air up there, and dry out anything that might be damp? Disadvantage: hot humid air in the upstairs living space, but I'm not using the upstairs now.

The attic and underside of the sheathing were inspected when the tarp was installed, and no damage was found. But as someone mentioned to me in a private message, condensation may be collecting under the tarp and getting into the sheathing.

Some nice dry, cool, sunny days sure would help.

Safety recall date: August 4, 2021 ....... fire safety recall for dehumidifiers; http://www.cpsc.gov/Recalls/2021/two...-fire-and-burn ..... is your dehumidifier one of the two million on the list that were sold before September 1, 2017.

Something to look at for second home owners who leave their dehumidifier running while they are away for a number of days or anyone using one of these widely used, home dehumidifiers.

Is best to TAKE IT BACK to Walmart or wherever for a refund and get a different dehumidifier ...... www.newwidetech.com/en/news.php?act=view&id=9

I was unaware of this and I do indeed have one of the recalled units. Thank you.

Thanks, FLL! I was just one model number away...:eek:

I had a dehumidifier that was part of a previous recall.

They sent me a check but it was somewhat offset by the $30 recycling fee at the town dump.

Now I have another recalled unit that is on the latest list.

Grrrrrr!

I have a brand new dehumidifier in the basement that's too heavy to take upstairs, so I'll need to buy a new one for upstairs.

Thanks FLL....checked mine and in the clear

Given the unusual time lag — recall August 2021 for dehumidifiers sold prior to 2017 — the problem is probably that a mechanism to prevent overheating wears out. Our Danby, purchased in 2018 from an excellent seller on eBay as a new but discontinued model, is on the list. It has always occasionally shut itself down for a while and then re-start, which I assume is the overheating prevention part kicking in. But we'll get rid of it.

Also interesting that just slightly over 100 of the more than 2 million sold have been reported to cause fires in models that haven't been sold for years but could be that most of those dehumidifiers had already croaked because the life span tends to be only 2-4 years.

Still hoping for feedback on whether people run the air conditioner and dehumidifier simultaneously.

My research on this found that all dehumidifiers put out quite a bit of heat, which will necessitate running the air conditioner. In my basement the dehumidifier very effectively removes humidity but has permanently raised the temperature down there about 10 degrees (60 to 70).

Yup. We have central air and a dehumidifier in the basement.

Sent from my SM-G950U using Tapatalk

We also have AC and dehumidifier in basement. But even on the hottest days, basement is cool, so we have never run AC.

I would not run AC and dehumidifier simultaneously. I think either alone is sufficient, and as you suggest, it's a huge load on the AC, especially in the attic on a hot day

We run central air for the entire house and dehumidifier in the basement. We also run ceiling fans in the high ceiling rooms to help circulate the air.

If you have water in the insulation in your roof no dehumidifier is gonna get it out. You're gonna have to rip the outside or the inside off and replace the insulation. Or you risk mold. Probably better to do inside because if that's plaster board it might be wet too. Might be just a small section that got wet.

I don't recommend Pro's very often, but I think you should get some opinions. If you did contact a pro they would have probably started drilling holes in the roof and pumping dehumidified air through it. It may have sat too long now for that option to work.

You don't want a new roof and then have to pull it off.

Good points. This post also begs the question of soffit and ridge vents--do you have them?

Soffits: yes. Gable vents: yes, but partially blocked at one end due to raised ceiling. Ridge vents: not currently. They will be installed with the new roof.

The AC cools the upstairs very well, but does not remove enough humidity, hence mold on the window frame around the AC and in the double-pane window next to the AC. I ran the AC on "dry" and the problem seemed to get worse. That's why I'm considering adding a dehumidifier, but I'm concerned about the amount of heat that a dehumidifier introduces.

You may want to ask the roofer.
Usually not both ridge vent and gable vents.

Yes--definitely get a pro opinion here. I do not know what mix of vents you need, but without the right airflow, you are unlikely to solve the problem by just adding more machinery

Good point, John. I believe I've read that. The house desperately needs ridge vents.

Update on dehumidifiers
 

Based on advice here I did add a dehumidifier upstairs and on very hot days I run it and the air conditioner at the same time. Electric bill has been very high this summer, but the upstairs is finally livable.

I'm happy with both of these units I bought this year:

Basement: Frigidaire 35 pints. https://www.homedepot.com/p/Frigidai...33W1/312539821

Upstairs: GE 22 pints. https://www.homedepot.com/p/GE-22-pt...22LA/315445853 Pretty noisy, so don't plan on running it in your bedroom at night.

I had to get a lighter unit for upstairs to be able to carry it up the stairs. I assume a basement would be more humid than the upstairs, hence the higher capacity bucket for the basement. I empty each bucket once a day and that seems sufficient to keep the humidity at around 50%.

The biggest concern with these machines is the high number of reviews that say they last only a couple of years.

"Gable vents work fine by themselves but what we have learned through research is that if you have a proper ridge venting system then you should block off the old gable vents. It turns out they work against one another and pockets of dead air begin to form in areas in the attic and that's not what you want." https://www.capitalgazette.com/busin...626-story.html

I forgot to ask the roofers about this. I will have this taken care of at some point.

True. Was told the same when I had my roof redone in 18.


Sent from my iPhone using Winnipesaukee Forum mobile app

I think I’ve heard that too. You need flow and if you do both it messes it up.

Those reviews are right. Gosh I bought so many of those POS dehumidifiers.
A friend of mine had the same problem and found one of those old ones with the big exposed coil on the back being thrown out. Super inefficient but damn thing keeps running.
I even bought an $800 commercial one and that died too. But they did warranty it and sent a brand new one, I sold it sealed as new.

The best solution would be even better if you didn't have to monitor it and dump the bucket. I have seen them connected to drain into a reservoir with a pump and float that will empty automatically. Amazon has one:

https://www.amazon.com/Little-554435...NsaWNrPXRydWU=

I have a friend who hooked up a boat bilge pump in a bucket with a 12 volt battery on a trickle charger to accomplish the same thing.

You only need to run the drain hose outside or into a sink and then you can forget about it. You won't need to empty the bucket again.

I once saw a display where the homeowner pumped the water up from the basement and out to what looked like a pretty sprinkler showering plastic flowers in the side-yard. Pretty clever/cute.