Author Topic: Help! Mold everywhere... how to stop?  (Read 17794 times)

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Re: Help! Mold everywhere... how to stop?
« Reply #50 on: December 25, 2015, 02:31:46 PM »
Any source of moisture has to be eliminated
I resemble that remark.

Thegoblinchief

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Re: Help! Mold everywhere... how to stop?
« Reply #51 on: December 26, 2015, 09:27:02 AM »
We ran into this issue. Had moisture condensation so bad on the Windows that mold/mildews stuff was growing on the dusty surface of all the flat vinyl window surfaces (middle of the double hung, and the bottom sill of all the windows). It was pretty gross by the time we realized what was happening.

Remediation steps that helped us:

1. Running furnace fan 24/7 so the dehumidifier we need in basement pulls humidity out of whole house, not just basement.

2. Kicking heat up a tad.

3. Not just running shower vent fan but also squeegeeing the walls down so most residual humidity went down the drain instead of needing to evaporate.

4. I'd already given up on line drying indoors earlier in the year.

Question: best chemical to use in spraying down surfaces? Our vinyl Windows have a small groove between glass and the sill that liquid pools in and the mold has been regrowing from there. I have both bleach-based Tilex and Moldex bottles.

sweettea

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Re: Help! Mold everywhere... how to stop?
« Reply #52 on: December 26, 2015, 10:40:29 PM »
For this reason I will not air dry clothes indoors as all the water in the wet clothes stays in the house.. Each pound of water will take 970BTU's to vapourise the water into steam in the dryer.. If you air dry inside the house, it will still take 970BTU's/lb.. if you dry in the dryer it will be the same amount of energy whether you use the dryer or the house heating system.. Not EXACTLY true because the discharge temperature of the dryer exhaust will be warmer. Also if you heat the house with gas and the dryer is electric then the electric will of course be more expensive.

Difference: airdrying means those 970 BTUs stay inside as heat, dryering means they go outside wastefully? Perhaps there's something I misunderstand about dehumidifiers... Thanks!

Yes at first galnce you would think thats how it works but in reality the energy it takes to evaporate the water is whats called latent heat. "Latent" means hidden. in other words you burn gas or electricity to evaporate the water from the clothes inside the house but the water is now in the atmosphere.

Then the next night when the house cools below the dewpoint (the temperature at which the air cannot hold water anymore because it has reached 100% relative humidity, warm air holds much more water than cold air.. so as you ccol it the ability to hold moisture goes down) the moisture will condense everywhere inside the house.

So guess what happens when you heat up the house again?.. Yup you increase the air temperature but part of that heat goes into evaporating all that moisture all over again.

So you waste energy over and over by re-evaporating the same moisture.. Oh and of course its feeding the mold over and over too.

So its much better to use an electric dryer to dry your clothes, get the moisture ut of the house and then your only evaporating all the water from the clothes just once, rather than over and over.

I communicated my idea badly. Suppose you have a perfectly airtight, moldproof enclosure, which transmits heat to a house but does not transmit any water or air to the house. Suppose you linedry inside this enclosure, and also put a dehumidifier into the enclosure.

Assume it takes 970 btus to remove water from a unit of clothes in the dryer, and also 970 btus to remove that much water from air on a dehumidifier. Also assume no energy is stored in liquid water condensed from gaseous water evaporated from liquid water.

With such assumptions, the airtight chamber would airdry clothes, then spend 970 btus in heat condensing the water, then those 970 btus of heat would transmit to the house. Meanwhile, the dryer makes those 970 btus go outside.

Is this a valid line of reasoning? Could I build a 'dryer' in this fashion (ignoring for the moment the problem of airtight moldproof enclosures)?

</tinkering>

Thanks!

-someone who clearly doesn't understand hvac.

totoro

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Re: Help! Mold everywhere... how to stop?
« Reply #53 on: December 27, 2015, 02:32:42 AM »
You can use a dehumidifier to dry clothes inside - some places like Sweden have a separate drying room with a dehumidifier.

It appears that your question is, again, whether it is cheaper to use a dehumidifier than a dryer to dry clothes.  It might be in some cases but you have mold.  Mold is a very serious health issue.  You need to get rid of it and stop the conditions that encourage it as a priority.  You seem to want to leave the temperature down and dry your clothes inside again using the dehumidifier so you can save money. 

Bottom line is that dehumidifiers are useful during periods of damp weather, but are unlikely to stop mold growth by themselves.  They are also much more efficient when the air temperature is warmer.   Turn up the heat, stop drying your clothes inside, put lids on pots when you boil stuff and keep using the dehumidifier.  Remove existing mold thoroughly.

Mold will remain active as long as the humidity remains high, usually 60% or higher. Therefore, if you lower the humidity with a dehumidifier to 50% and maintain it there, the mold will become inactive and not get any worse. However, it will not die and disappear and it will still emit mold spores.

You have stated that, "the mold seems thoroughly extinguished and not growing back, nor am I permitting condensation without cranking up the dehumidifier".

That is pretty remarkable for only 10 days of using only a dehumidifier plus not drying clothes inside given that you had mold growing everywhere - doors, windows, books, wicker baskets, windowsills. How did you get the mold off of the surfaces? Also, have you checked hidden areas like wardrobes, under carpets, behind curtains and furniture?

Finally, here are some of the common symptoms to watch out for with mold in the environment:
Chronic colds    Flu-like symptoms Chronic headaches    Bloody noses  Coughing    Arthritic-like aches  Sinus congestion    Equilibrium or balance loss Upper respiratory distress    Irritation of the eyes, nose or throat  Skin rashes    Nausea


former player

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Re: Help! Mold everywhere... how to stop?
« Reply #54 on: December 27, 2015, 02:40:17 AM »
I communicated my idea badly. Suppose you have a perfectly airtight, moldproof enclosure, which transmits heat to a house but does not transmit any water or air to the house. Suppose you linedry inside this enclosure, and also put a dehumidifier into the enclosure.

Assume it takes 970 btus to remove water from a unit of clothes in the dryer, and also 970 btus to remove that much water from air on a dehumidifier. Also assume no energy is stored in liquid water condensed from gaseous water evaporated from liquid water.

With such assumptions, the airtight chamber would airdry clothes, then spend 970 btus in heat condensing the water, then those 970 btus of heat would transmit to the house. Meanwhile, the dryer makes those 970 btus go outside.

Is this a valid line of reasoning? Could I build a 'dryer' in this fashion (ignoring for the moment the problem of airtight moldproof enclosures)?

</tinkering>

Thanks!

-someone who clearly doesn't understand hvac.
If I had an outside which was transmitting heat to the house, then I would assume that outside was warmer than the inside and therefore more likely to dry the clothes quicker and using less energy, so I would dry the clothes outside if at all possible, using the sunniest, windiest spot available.

With a bit of care and timing, in many climates drying outside works pretty well.  It's how humans survived for all those hundreds of years after the common usage of washable clothes and bedding but before the invention of HVAC, dehumidifiers and central heating.

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Re: Help! Mold everywhere... how to stop?
« Reply #55 on: December 27, 2015, 08:08:34 AM »

Question: best chemical to use in spraying down surfaces? Our vinyl Windows have a small groove between glass and the sill that liquid pools in and the mold has been regrowing from there. I have both bleach-based Tilex and Moldex bottles.

I've had success killing the black mold in our bathroom grout and silicone with a paste made of baking soda, liquid Castile soap (dr bronners), and a few drops of tea tree oil. The idea is to kill with antibacterials. I leave the paste in overnight and rinse / dry in the morning. So far it's worked well.

Bleach doesn't seem to kill the mold -- it just bleaches it.

I've read that a hydrogen peroxide solution will also work.

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Re: Help! Mold everywhere... how to stop?
« Reply #56 on: December 27, 2015, 10:41:34 AM »
I can't believe how stubborn OP is. This is one of the most ridiculous and infuriating threads I've ever followed on this forum.


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Re: Help! Mold everywhere... how to stop?
« Reply #57 on: December 27, 2015, 10:53:25 AM »
We tried. Sweettea will find out soon enough on their own.

"A foole and his money be soone at debate: which after with sorow repents him too late."
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sweettea

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Re: Help! Mold everywhere... how to stop?
« Reply #58 on: December 27, 2015, 11:35:00 AM »
Dear Mustaches:

Please rest assured that I have been facepunched quite enough. In my previous state, I thought mold was merely a little disgusting-looking, and problematic when it got on books, but no big deal. I have been convinced by all yall that mold is the equivalent of a velociraptor gnawing on my house. My followon question came about because a dehumidifier is an intriguing engineering feat to me and the idea of a low-temperature moisture-remover set my gears turning.

Rabbi Daley provided an excellent set of advices, in particular. When warmth returns, I shall attempt to sunlight my belongings for a week. Meanwhile I can count the belongings which I have not rearranged to check for mold.

I apologize for being infuriating.

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Re: Help! Mold everywhere... how to stop?
« Reply #59 on: December 27, 2015, 01:15:24 PM »
Sweettea, my apologies for heaping on and assuming the worst after your continued line of questioning. I, and I'm sure others here, are certainly thankful to hear that you are moving forward and treating the problem properly.

Regarding the dehumidifier angle against energy efficiency: From an artificial, mechanical engineering standpoint, it roughly takes just as much energy to condense water out of the air as it does to evaporate it. This is why dehumidifiers are such an energy suck to begin with, and why drought stricken areas such as California are turning to recycling waste water and desalination - as expensive as these methods are, it's still cheaper than industrial-scale water condensers. Dehumidifiers are no more complex or amazing than air conditioners, and in fact work the exact same way. The only difference is that you have both ends of the device indoors with the waste heat re-warming the air cooled over the coils to extract the water before being pumped back into the air - same guts but with none of the advantages of beneficial heat exchange.

The reason why heating the air is so much more efficient (mostly time-wise) than dehumidifying for drying is because heat not only accelerates evaporation, it permits the air to hold more water. Unfortunately, that removed moisture eventually has to go somewhere - and that somewhere is out into the world. There's a reason why people in the past didn't really wash their clothes in the Winter. A lot of these technical limitations is the reason why - the RH, the temperature, the ease of drying, etc. Dryers are a miraculous thing for allowing clean clothes during winter months. Could they be more efficient? Certainly! They're a pretty inefficient machine overall, but there are ways to gain and game that efficiency.

The real places where the greatest gains could be had to increase efficiency of a gas or electric clothes dryer when needed is the application of a counterflow heat exchanger between the exhaust air and a dedicated air intake for the dryer itself (something that houses really aren't set up to do), in addition to a high speed spin dryer to remove as much liquid water as possible through centrifugal force before evaporating the rest.

May this additional information help you to better tackle the efficiency issue going forward after resolving the health issue.

Edit: I'm adding a link to a few other alternative clothes drying methods. Some have utilized dehumidifiers in connection with dedicated wardrobes/rooms for drying, which may be in line with some of your earlier thoughts. Ultimately though with the power poured in, even if a dehumidifier and fan has the potential to be more efficient overall with the longer dry time, the system is still pretty well closed with minimal benefit to the rest of the house.
« Last Edit: December 27, 2015, 01:56:28 PM by I.P. Daley »

big_owl

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Re: Help! Mold everywhere... how to stop?
« Reply #60 on: December 27, 2015, 04:28:11 PM »
Dear Mustaches:

Please rest assured that I have been facepunched quite enough. In my previous state, I thought mold was merely a little disgusting-looking, and problematic when it got on books, but no big deal. I have been convinced by all yall that mold is the equivalent of a velociraptor gnawing on my house. My followon question came about because a dehumidifier is an intriguing engineering feat to me and the idea of a low-temperature moisture-remover set my gears turning.

Rabbi Daley provided an excellent set of advices, in particular. When warmth returns, I shall attempt to sunlight my belongings for a week. Meanwhile I can count the belongings which I have not rearranged to check for mold.

I apologize for being infuriating.

No worries, sweettea.  Sometimes there's a fine line between mustachian badassity and mustachian dumbassity.  Looks like you're keeping on the correct side of the line now...if the urge to save a few bucks on heating comes back any time soon just remember...it literally hurts to raise my eyeballs to look straight ahead when I'm off my meds.  You don't want that to be you...

Daley

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Re: Help! Mold everywhere... how to stop?
« Reply #61 on: December 27, 2015, 06:40:49 PM »
Edit: I'm adding a link to a few other alternative clothes drying methods. Some have utilized dehumidifiers in connection with dedicated wardrobes/rooms for drying, which may be in line with some of your earlier thoughts. Ultimately though with the power poured in, even if a dehumidifier and fan has the potential to be more efficient overall with the longer dry time, the system is still pretty well closed with minimal benefit to the rest of the house.

Follow-up to this little addendum and an effort to shift the topic towards alternative drying technologies. Before anyone gets too excited about the idea of doing a dehumidifier/fan/wardrobe setup, one should double check the math provided by the writer of that DIYWiki article. It's a bit skewed and biased, lacks substantial and practical evidence regarding general humidity and temperature levels, solid kWh usages (only napkin math estimates), mold risk, and the energy savings aren't anywhere near the 1/17th mark being boasted, as the math is... specious. One of the ironies of the article upon far closer inspection is this statement:

Quote
Why does it use less energy than a tumble dryer?
[snip]
The other use of energy in a tumbler is to turn the drum. Most tumble dryers have no drum bearings, and turn stiffly. This can take 100-200w. There is no such energy use with the dehumidifier.

[snip]
I find a 400W compressor based dehumidifier will dry a load of washing this way in 60 minutes after a 1400RPM spin. Towels and thick denims may require longer.

Now granted, I understand the point trying to be made. Electric dryers especially use considerably more than this (1800-5000W total), but the 400W dehumidifier is interesting - and it's probably running 100% of the time during that hour, making it about 0.4kWh per load roughly. Claims elsewhere are "as low as 0.15kWh per load" if you stretch the time out overnight, yet the price comparisons against electric dryers and energy usage with alternate models aren't consistent with these numbers reported, and appear to be far closer to that 0.4kWh in reality without even factoring additional power overhead for the fan and any potentially needed additional heat getting the dehumidifier up to its optimal efficiency heat range. The same high-RPM (1400+RPM) dryer spin-out reported on the 400W unit before going into an electric dryer shortens dry time to under 20 minutes per load. Michael Bluejay uses both this time estimate and an electric wattage estimate of 4400W for an electric dryer in his guide on saving energy on clothes drying. So, 4400/3=~1.467kWh per load. That's only a 3.67x power savings, and hardly the 17x numbers actually boasted about - and it probably gets worse with the average 1000RPM or slower spin-out when properly comparing apples to apples. Realistically at ~15/kWh, we're talking a difference at best of 16 a load. This doesn't factor further potential savings for those using natural gas, either.

The numbers on the DIYWiki also assume you're going to use this for 100% of your drying year round for every method.

Honestly, all of this just underlines the value of a high speed spin dryer across the board for overall energy and time savings. It also highlights the further annual marginal savings when you're only talking about using one of these methods for drying about 1/4th to 1/3rd of the year while line-drying the rest of the year. You're also talking about a larger footprint and extra effort to reinvent the wheel on something that bought used on both ends, run about the same cost to set up, but only if you already have the closet or wardrobe in advance.

Is it clever? Yes. Is it a potentially great energy savings? Ehh. Is it a more complex system? Yes. Does it come with greater risks? Possibly. I'm immensely frugal and practical, I'm even known for ranting about people who use more than 100MB of data on their mobile phones after all... which runs me dangerously close to the stingy line myself on occasion even if it is a reasonably justifiable rant. I'm also a dyed-in-the-wool environmental conservationist and advocate using less resources in general. Does it mean I'll be buying a dehumidifier to line dry clothes indoors after thoroughly dissecting the proposal? Probably not. There's a lot of trade-off and hidden costs with more mechanically complex systems, and we're pretty well talking about a savings of maybe $15-20 a year for most people who typically line dry in the first place.

Just some thoughts.
« Last Edit: December 27, 2015, 07:30:36 PM by I.P. Daley »

Exflyboy

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Re: Help! Mold everywhere... how to stop?
« Reply #62 on: December 27, 2015, 07:19:46 PM »
The theory of using the dehumidifier is sound, how well it works in practice is up for debate of course.

The theory: A dehumidifier is a heat pump that will have a coefficience of performance of say 3 to 1, for arguments sake.

This means you pump 1 unit of electical energy in to get 3 units of cooling on the cold coil (this is what condenses the evaporated water). The 4 units of "waste" heat come from the warm coil. (i.e the 3 units from the cold coil plus the 1 unit of electrical energy).

so you put the wet clothes in the sealed closet the cold coil gets cold and the warm gets warm (duh).. and the closet gets a bit warmer than ambient due to the extra unit of electrical energy.

The nice warm air then evaporates, and each pound of water will take 970BTU's from the warm air in the closet... this evaporation will drop the closet temperature somewhat which will make the air less able to evaporate moisture.. so its a bit of a balancing act as to how fast water will be evaporated.

The warm moist air hits the coling coil, condenses below the dewpoint and the resulting water is collected inside the drip tray.. The cold air is then re-heated by the warm coil and you have warm air at a very low humidity ready to evaporate more water.

Bottom line.. In theory you are getting 3 times the dehumdifying than you are actually paying for... i.e COP= 3:1, so 3 units of dehumidifying for 1 unit of electrical energy.

But here is the rub.. this is all fine in theory but unless you are blowing the air through the fabric then the water will only evaporate from the outside of the clothes.. so the max rate of water extraction will be limited by this fact.

The problem of course is that the dehumidifier doesn't care whether it is happily condensing water.. it will still use the same amount of energy to run no matter how much water is being extracted.

For this reason dehumidifiers are very good at dehumidifying air, but I suspect less so at drying clothes and the savings compared to an electric dryer are somewhat less than the theory would imply.

So I would agree with IP Daley's hypothesis that it is likely great in theory, but less effective in real life.

All this to say, dry your clothes on the line OUTSIDE the house in the Summer (unless you want the moisture to stop your nose drying out), but certainly if you have mold use the electric dryer during the Winter.

« Last Edit: December 27, 2015, 07:31:05 PM by Exflyboy »

justajane

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Re: Help! Mold everywhere... how to stop?
« Reply #63 on: December 27, 2015, 08:12:44 PM »
I think the OP should definitely use a dryer until the mold situation is solved, but FWIW I line dry a large percentage of my clothes and sometimes run a dehumidifier because it is better for the clothes. They last so much longer if you don't dry them. Plus no shrinkage. So the cost savings of having to buy clothes less often somewhat mitigates the increased cost of having to run a dehumidifier or increasing the heat.

Considering we've gotten EIGHT INCHES of rain in the past two days, our dehumidifier is working hard at the moment. 

pbkmaine

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Re: Help! Mold everywhere... how to stop?
« Reply #64 on: December 27, 2015, 08:25:47 PM »
I live in Florida, and except for a few delicate items of clothing, everything goes in the dryer. Humidity is the enemy here.


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Re: Help! Mold everywhere... how to stop?
« Reply #65 on: December 27, 2015, 08:43:08 PM »
Here in the Pacific Northwest where the state flower is mildew we also have to be very careful. Next door they are building this 3000sq ft house (monstrousity) and the framing has been soaked for several weeks day after day.

My fear is that they will wrap this thing in House wrap, put the roof shingles on and subesquently trap all that moisture in the timber of the house. Considering they have demolished several $1M+ homes due to black mold in recent years then as the homeowner I would be very concerned about this.

Personally I'd cover in in tarps until the Spring where it can dry out for a couple of weeks before I wrapped it.

flower

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Re: Help! Mold everywhere... how to stop?
« Reply #66 on: December 28, 2015, 01:03:54 AM »
Here's something I have always wondered about. When clothes are dried in the dryer, there are very few that need to be ironed. When they are line dried a lot more ironing has to happen.

I have always wondered how much electricity is really saved if you have to do a lot more ironing when you dry clothes on the line. Does anyone have ideas about this?


Frankies Girl

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Re: Help! Mold everywhere... how to stop?
« Reply #67 on: December 28, 2015, 04:40:39 AM »
Here's something I have always wondered about. When clothes are dried in the dryer, there are very few that need to be ironed. When they are line dried a lot more ironing has to happen.

I have always wondered how much electricity is really saved if you have to do a lot more ironing when you dry clothes on the line. Does anyone have ideas about this?

Irons don't use anything near the same level as a clothes dryer, but the best solution is: Buy clothes that don't need to be ironed.

I'm not trying to be funny; I realized a while back that certain items made out of certain fabrics wrinkle like crazy and always have to be ironed, so I got rid of them and replaced them with items that never have to be ironed no matter how they are washed/dried. It saved me so much time and frustration.

Exflyboy

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Re: Help! Mold everywhere... how to stop?
« Reply #68 on: December 28, 2015, 11:21:26 AM »
As pointed out earlier, it takes 970BTU's to evaporate moisture.

Whether that is done in the dryer or with an iron, the energy consumption is the same.. But of course if you iron indoors the moisture ends up inside the house. Thats a pretty small quantity though.

KiwiSonya

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Re: Help! Mold everywhere... how to stop?
« Reply #69 on: December 28, 2015, 12:24:21 PM »
Shit, this is my problem too. I get prolonged respiratory infections in winter due to mould. But was drying washing inside with dehumidifier on. Face punching accepted and practices will change.  I'm in New Zealand so enjoying summer right now but will sort my shit come winter. Thanks for the reminder not to be cheap.

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Re: Help! Mold everywhere... how to stop?
« Reply #70 on: December 28, 2015, 06:13:57 PM »
Fortunately, I'm in a dry climate (central Texas) and don't have this issue. Running the electric dryer costs me at least 4x what running the gas furnace does on an equivalent BTU basis.

When I'm not line (rack) drying clothes inside in the winter, the humidity is often down to around 20% RH (yes, we keep it too warm. Compromises) - with a couple of wet loads spread around, it might get to 40%, peak at maybe 50% briefly if I just opened the dishwasher too, or there is cooking going on.

We've never had an indoor mold issue.

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Re: Help! Mold everywhere... how to stop?
« Reply #71 on: December 28, 2015, 06:24:04 PM »
TomTX, I don't understand the concept of 20-40% humidity (see attachment) . As mentioned upthread, mildew is the state flower out here!

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Re: Help! Mold everywhere... how to stop?
« Reply #72 on: December 28, 2015, 06:36:24 PM »
Fortunately, I'm in a dry climate (central Texas) and don't have this issue. Running the electric dryer costs me at least 4x what running the gas furnace does on an equivalent BTU basis.

When I'm not line (rack) drying clothes inside in the winter, the humidity is often down to around 20% RH (yes, we keep it too warm. Compromises) - with a couple of wet loads spread around, it might get to 40%, peak at maybe 50% briefly if I just opened the dishwasher too, or there is cooking going on.

We've never had an indoor mold issue.

Right thats the opposite "problem" where you want moisture inside the house. In that case you still need the 970BTU's to evaporate the moisture.. but its a lot cheaper to burn gas then electricity.

Exflyboy

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Re: Help! Mold everywhere... how to stop?
« Reply #73 on: December 28, 2015, 06:45:13 PM »
TomTX, I don't understand the concept of 20-40% humidity (see attachment) . As mentioned upthread, mildew is the state flower out here!

Exactly, never one to miss a teaching moment.. notice how the high humidity (relative) happens when the temperature is quite low.

In fact the RH of air when its cold with ice all over the place outside will be darn near to 100%.

So the question is what does "Realtive Humidity" mean. Well it is a measure of the moisture content of the air (in pounds of water in the English system of units), divided by the MAXIMUM moisture content of water in the air at THAT temperature.

As warm air can hold a LOT more water than cold air.. if you take cold air at close to 100% RH and warm it up but don't add any moisture the RH will drop rapidly.. because the ratio of actual moisture compared to the moisture which CAN be held at the higher temp goes way down with rising temperature.

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Re: Help! Mold everywhere... how to stop?
« Reply #74 on: December 28, 2015, 07:05:15 PM »
TomTX, I don't understand the concept of 20-40% humidity (see attachment) . As mentioned upthread, mildew is the state flower out here!

Exactly, never one to miss a teaching moment.. notice how the high humidity (relative) happens when the temperature is quite low.

In fact the RH of air when its cold with ice all over the place outside will be darn near to 100%.

So the question is what does "Realtive Humidity" mean. Well it is a measure of the moisture content of the air (in pounds of water in the English system of units), divided by the MAXIMUM moisture content of water in the air at THAT temperature.

As warm air can hold a LOT more water than cold air.. if you take cold air at close to 100% RH and warm it up but don't add any moisture the RH will drop rapidly.. because the ratio of actual moisture compared to the moisture which CAN be held at the higher temp goes way down with rising temperature.

Lightbulb moment. Thank you! Teachable moment indeed. I feel smarter now.

TomTX

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Re: Help! Mold everywhere... how to stop?
« Reply #75 on: December 28, 2015, 07:32:53 PM »
TomTX, I don't understand the concept of 20-40% humidity (see attachment) . As mentioned upthread, mildew is the state flower out here!

If you take that 39F/92% Relative Humidity air and heat it up to 70F, you drop the Relative Humidity to a bit below 40%.

Exflyboy

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Re: Help! Mold everywhere... how to stop?
« Reply #76 on: December 28, 2015, 09:31:16 PM »
TomTX, I don't understand the concept of 20-40% humidity (see attachment) . As mentioned upthread, mildew is the state flower out here!

If you take that 39F/92% Relative Humidity air and heat it up to 70F, you drop the Relative Humidity to a bit below 40%.

Correct, the tool most comonly used to determine this is the psychrometric chart shown below. This is very handy because it shows you the energy state of air at any condition (in BTU's per pound of air).. as the rate of change of energy is power (i.e BTU/Hour, where there are 3413BTU/Hr per killowatt), you can calculate how much power you have to pump in (or extract from) to the airstream when you want to change the state of the air at a known flowrate.

Its a very handy tool...:)

http://www.truetex.com/psychrometric_chart.gif

Bearded Man

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Re: Help! Mold everywhere... how to stop?
« Reply #77 on: December 28, 2015, 10:35:15 PM »
Seriously, turn up the heat and go get a dehumidifier ASAP! You are being a penny wise and pound foolish right now. The money you're saving by keeping your house at 58, not using the clothes dryer, and not investing in a dehumidifier is going to go right out the window when your house is condemned for mold! You will pay thousands and thousands of dollars to get mold taken care of, and who knows what your homeowners policy will say covering that if they determine it is caused by homeowner "neglect". Seriously! Alarm bells should be going off in your head right now! I'm not saying you need to go total unmustachian here and crank the heat to a permanent 78 and use the dryer for everything; but, getting the house back up to the mid-60s and dropping $150 for a dehumidifier (or getting on used on CL if there is one available for pick up TODAY), and using the clothes dryer a bit more for the next few months are smart, commonsense things that will end saving you money in the end.

This.