Sopping Wet Windows

I do not understand.
Last couple of years, in this drafty rental, I put up clear plastic on the windows, cut to fit, heavy stuff, that hangs off a curtain rod.
Last winter I added fairly loose styrofoam interior shutters.
Some of the windows have drapes too.
All years on some windows I taped the plastic to the frame on the sides and bottoms.

This year, with NO additions made to the process at all, ALL of the windows are water harvesting. The condensation is amazing. It's soaked the tape off, the window ledges are molding. They are sopping wet.

Nothing changed since last year!!

Any suggestions what to do? Not even sure what could be doing this.

I dealt with that when I used a ventless natural gas heater for a few years. You certainly have my sympathy. Do you know your humidity now versus previous years? If the window are double-paned maybe they lost their seal, but it would likely be odd if they all did at the same time. Can you cover the outside of the windows? Maybe that would get the glass closer to room temp and above the dew point.

No clue of humidity. The heater dries it out horribly in here.

Double pane windows, crappy cheap ones (I'm in a rental) and installed badly (off square) and the wind comes trough the frames and the walls around them, as well as the glass.

No way I can think of to cover the outside, the exterior is vinyl siding, so it isn't smooth, and there's no where to hook anything. And the frames are half the problem.

Wonder if the wet is coming  in the frames... and if so, why it didn't last year.

Has the outside weather pattern changed much? Are you getting a lot more temps with above freezing during the day and below at night? We get a lot of that, so we spend a *lot* of time around the dew point.

Good luck at figuring it out!

Maybe the insulation in the walls settled, or was damaged by vermin and is allowing more air through the cracks? Maybe tape some plastic or bubble wrap directly to the window. You will not get that tiny bit around the edges, but it would likely be better than nothing.

We did just have a lot of foggy days.

You know what has changed....
A) There's a new crack where the wall meets the ceiling in the bathroom. I suspect the foundation has shifted a touch. Bet those windows are even less square now...

AND
B)  Due to finances we are keeping the thermostat lower than we like. The heater isn't kicking on as much, and it's probably always dried the air so hard there was nothing to condense.

Hm...

Have to think on how to deal with it if it's those.

I don't know which trashes my health worse, the cold drafts, the lack of humidity due to the heater, or the mold. Bad set of options there. I know we can't afford to keep the heat higher.

I'm not sure what's different this year for you.

As I've learned more about condensation, it basically comes down to the dew point temperature of the air that touches the inside surface of the window vs the temperature of the inside surface of the glass.  If the glass is colder, you'll get condensation.  If the glass is below freezing, you'll get frozen condensation (frost/ice).

The middle of the window is generally better insulated than the frames (due to the frames transferring more cold to the glass).  The bottom of the windows are usually colder than the top since the heat of the room is warmer near the ceiling.  That's why frost/condensation normally starts at the bottom and sides of the glass.

We have very cold glass temps in my house and we don't have forced air blowing the heat of the room up against the glass to keep it warmish.  So we've dealt with condensation and frost a lot in this house.

If your curtain system allows the room air to travel between the curtain and the glass, it will condense, cool and drop.  That drags more warm, humid air behind the curtain to replace it and condense.  So you end up with a conveyor belt of humid air that condenses on the glass.  So keeping humid room air from slowly passing by the glass should help.

On the other hand, a fan blowing warm air at the glass may warm up the surface of the glass so the temperature rises above the dew point.  That's why they often locate heat vents below windows on houses.

The solution I've arrived at is detailed here: Preventing condensation on windows in the winter

I bet it's the lower thermostat setting.  That allows the glass to get colder and condense more liquid out of the air.

It's been humid, here - with temps above freezing during the day, and below, at night, with more fog than normal. I've noticed more moisture around our garage window, where there's less insulation and the door seals are in need of replacing. If you're adding a settling foundation...
So, would you be able to add a couple space heaters?

Pearl Sutton wrote:We did just have a lot of foggy days.

Fog is 100% humidity. I suspect you got a slug of extra moisture inside the house from leaks and even from opening doors. It will take a little time for that to settle down. Fans help, venting to outside helps, and of course higher temperatures help to raise the dew point.

Sad to hear finances are tight. Lots of people are feeling the pinch right now.

Sorry to hear about the situation. I've been in similar many times.

Maybe a dehumidifier would be more affordable to get to the ideal humidity.

I'm not sure if it's possible as I haven't actually tried it yet, but maybe taping a sheet of plastic at the bottom and forming it into a funnel to collect the water for later use would be a temporary solution.
If it worked, maybe a silicon bead could attach something that allows to take the sheet off and on without using more tape etc., maybe a zipper.?

We have several space heaters, they don't run at the same time, we add heat where we are. I also have some serious fans, guess I'll be opening it all and blowing out the space.

I'm thinking on how to change all the factors people are suggesting. There's got to be a way to stop this. I'll be thinking on it in bed tonight, I know me, I'm like that. I do a lot of thinking at night.  :D

On the plus side of the weather and drafts, we have our winter extra fridge up and functioning. In the summer it's called the garage, in the winter it's the big fridge! There's no heating that area, no matter what you do. All you can do is use it as it is.

:D

Warm air can hold more moisture than cold air. You can get your house hot just for a bit, then vent all the moist air and replace it with cold, drier air from outside. We do this frequently through the winter, whenever the temperature hovers around freezing and we don't have the stove going all the time. Humidity starts to build up. It's probably a lot easier to do in our house, since we just have a loft and a clear path for air to exit out the upstairs windows - and a tiny house. As long as you get the air flow right, it should help any house, though.

Howdy,

Are you heating with propane?

https://www.quora.com/Why-does-burning-propane-in-a-room-create-condensation-on-the-windows

I think the propane only causes condensation if it is exhausting into the room (vs outside).  So likely an issue for little portable propane room heaters.

randal cranor wrote:Howdy,
Are you heating with propane?

https://www.quora.com/Why-does-burning-propane-in-a-room-create-condensation-on-the-windows

Interesting, thank you! Yes, the heat pump does back up to propane any time the temp goes below 36.
I'll add that to my list to consider.

Today I have coverings off the windows, fans blowing air at them to dry them off. It's too cold to open the house and blow moisture out, but the more I think on it, it was very humid when I covered them, and we were getting fog every morning. It's freezing now, there won't be much fog anymore.  
Having to clean the mold off of them all too.
Considering the water collection thing idea, that would at least keep the ledges from molding.
Logistics in this place are bad for doing any of this.

New house, very well insulated, very good windows, heat registers below the windows, still have condensation.

Our house is an older build with single glazed windows and minimal insulation. This year we have been heating the main living rooms with the woodstove, and only turned on the central heating for a few particularly cold days, when the outside temps were well below freezing.

Our condensation issues this year have been bad. Like, black mould growing on the windows  bad.

In part, we do dry our laundry hanging indoors. We don't have a tumble drier and our weather has been consistently damp so the outdoor line has been useless.

I bought a dehumidifier 2 weeks ago to use upstairs in the unheated portion of the house. It has pulled an incredible total amount of moisture out of the air. I've been emptying the 3 litre catch container twice a day, and it has been running non-stop apart from when we are sleeping. I have noticed that the amount of condensation upstairs has been decreasing, and the dehumidifier now only comes on about half the time.

My supposition is that, due to the damp from drying clothes and not using the heating, the fabric of the upstairs of the house had absorbed a lot of moisture - in the plasterwork, carpets, woodwork, furniture etc... Over time, with the dehumidifier running, that has slowly dried out. The black mould has stopped and the window condensation has substantially reduced.

Separately, my dad has lent me a window water vacccum. It takes about two minutes to do all the windows on a floor, and sucks up the moisture to be tipped away. It is quick and highly effective, and it has the added advantage over using a cloth that you don't then have a damp cloth that needs drying which just returns the moisture to the air again. Early on when I started using it, and when our moisture issues were still really bad, the tank would fill up from a single window each morning.

Karcher Window Vac

Pearl Sutton wrote:

randal cranor wrote:Howdy,
Are you heating with propane?

https://www.quora.com/Why-does-burning-propane-in-a-room-create-condensation-on-the-windows

Interesting, thank you! Yes, the heat pump does back up to propane any time the temp goes below 36.
I'll add that to my list to consider.

Today I have coverings off the windows, fans blowing air at them to dry them off. It's too cold to open the house and blow moisture out, but the more I think on it, it was very humid when I covered them, and we were getting fog every morning. It's freezing now, there won't be much fog anymore.  
Having to clean the mold off of them all too.
Considering the water collection thing idea, that would at least keep the ledges from molding.
Logistics in this place are bad for doing any of this.

Hi Pearl,
It sounds like a classic case of high humidity during the heating season.  When the glass in the windows cools down to a certain point and the room humidity is above a certain point you get condensation on the glass which drips down to the frames and moldings. If you are using your central furnace less and space heaters more then that would cause a shift in how much warmed moving air is hitting the glass thus lowering the dew point causing more condensation. Its a major problem here due to our really cold outsides and warm insides. The central furnace also lowers humidity by bringing in outside air which is cooler and has less humidity in it to replace its combustion air. Usually you solve it by lowering the relative humidity in your heated space. I would start with a humidistat often an all in one thermostat has it built in then if your humidity is way too high a dehumidifier. When canada adopted a really tight house building code and before we understood the benefits of Heat recovery Ventilators and fresh air we used to refer to it as sick building syndrome.
And on that cheery note!
Cheers,  David

Where I'm at on this:
I have a bad storm coming in. Yesterday I opened up all my window covers, used big fans to dry it all out. Could not open the house for venting, was low 30's out there. Made the house cold enough to uncover those bad windows.
I cleaned all of them, then closed them back up, used no tape, just loose plastic and loose styrofoam covers, and drapes.

When the weather breaks again, I'll check them, but at the moment, they are closed for the duration.

I'm hoping that when I sealed them before it was too humid (it probably really was) and that this will be enough to stop the heavy water flow.
Current prediction has us at -30F wind chill, from the north, and the north windows are the worst, most of the covered ones that I messed with yesterday are on the north. At this point, I'll take wet windows over that wind coming in too easily.

Pearl Sutton wrote:Where I'm at on this:
Yesterday I opened up all my window covers, used big fans to dry it all out. Could not open the house for venting, was low 30's out there....

I cleaned all of them, then closed them back up, used no tape, just loose plastic and loose styrofoam covers, and drapes.

So you dried the individual window areas, but weren't able to vent the house? The problem I see is that you still have that moisture in your building - in the air, or as dampness in the fabric of the building. Those windows will still be a cold trap, and moisture focus.

You mentioned at various points that you have some drafts around these windows? We have issues with ill-fitting windows and doors. Each autumn we have an afternoon going round plugging all the gaps around window frames. I use a thin blunt blade, like a butter knife, and strips of kitchen roll paper. Then in spring when you need to just open then windows, the paper falls out. It makes a huge difference to the feel of a room before/after.

Michael Cox wrote:

Pearl Sutton wrote:Where I'm at on this:
Yesterday I opened up all my window covers, used big fans to dry it all out. Could not open the house for venting, was low 30's out there....

I cleaned all of them, then closed them back up, used no tape, just loose plastic and loose styrofoam covers, and drapes.

So you dried the individual window areas, but weren't able to vent the house? The problem I see is that you still have that moisture in your building - in the air, or as dampness in the fabric of the building. Those windows will still be a cold trap, and moisture focus.

Yup. Best I can do right now. It's freaking cold. I am NOT opening up this house right now. It has enough drafts that there is air flow. It really was seriously humid when I closed them up. It's not now.

You mentioned at various points that you have some drafts around these windows? We have issues with ill-fitting windows and doors. Each autumn we have an afternoon going round plugging all the gaps around window frames. I use a thin blunt blade, like a butter knife, and strips of kitchen roll paper. Then in spring when you need to just open then windows, the paper falls out. It makes a huge difference to the feel of a room before/after.

I do something similar.

Would you consider getting a dehumidifier? Given your needs it really does seem to be necessary.

There are two types.

Compressor types - work a bit like a fridge, or air conditioner. They do not work well at temperatures below about 20 degree C, so not good in colder parts of the house.

Desiccant types - they use a rotating disc of an absorbent material. Moist air from the room passes through the disc and the moisture is absorbed. The disc rotates and the damp part moves to a heated section, and drives the moisture off. The damp air coming off the heated pad then goes through a heat exchanger, where it is cooled down by the incoming cold air, and the water condenses out.

The huge advantage of the desiccant types is they work right down to near freezing air temperatures without dropping efficiency, plus they also warm the air a little which takes the chill off unheated spaces.

Our desiccant dehumidifier does a good job of quite a large area in the unheated portion of the house.

Michael Cox wrote:Would you consider getting a dehumidifier? Given your needs it really does seem to be necessary.

The heat pump here dries the air to the point of my skin cracking and bleeding, and my sinuses bleeding. My face was shattered in a car wreck years ago, I have had ear-sinus infections running off and on for the last 40 years, and definitely on for the last 5, and the dried to the point of cracking and bleeding trashes my health horribly. The main problem here in the winter tends to be TOO LOW humidity.

The windows have never condensed before. It's something in what I did differently this year. And the main thing I did differently was seal it all up when it was very humid.

If I added an appliance, it would be a humidifier, not a dehumidifier. This place is DRY. Sparks off the cat, I have to ground my laptop for contact shock type dry. High humid is not the issue here in winter.  

I do appreciate the info, I had never thought much about dehumidifiers, now I know more, thank you!

And I DO appreciate the help, there are simply different factors going on here than you have there. The serious dryness of the air is why the condensation surprised me. It's backwards of the usual.

:D

I would say a dehumidifier is certainly in order. I've found the compressor types far more common and less pricey and in a heated building fine. They do heat your space a little as well.

Pearl Sutton wrote: The main problem here in the winter tends to be TOO LOW humidity.

The windows have never condensed before. It's something in what I did differently this year. And the main thing I did differently was seal it all up when it was very humid.

It does sound very strange then. Can you get your hands on a humidity monitor, and actually get a measure of the humidity in different parts of the house?

I think you mentioned earlier that you are not heating these rooms, but are heating others? Warm air holds a lot more moisture than cold air. As warm air moves around the house and cools, it actually increases the % humidity. So you may have low humidity in the heated living spaces, but dam issues in the cooler rooms.

Pearl Sutton wrote:. Could not open the house for venting, was low 30's out there. Made the house cold enough to uncover those bad windows.

The key to venting humid air is you need to get the air in the house as warm as you can BEFORE venting. Then the air has picked up more moisture from all your stuff - windows, curtains, furniture, etc. If your house is cold to begin with, all that moisture is still just sitting there in your house.

We just did some venting cause I had to air dry a bunch of drapes inside and it got quite humid. Got the temperature up above 30°, which, let's see, is 86° in your world. It's, hmmm...5F outside here right now. Perfect venting conditions, since the air will be nice and dry. I opened a window upstairs, then went and opened a door downstairs on the opposite side of the house. In our tiny space, I only left things open for about ten minutes. Then I closed everything up and ripped the stove to warm it up again. Didn't take long since the mass in the house was all still warm.

Yesterday morning before I did this, humidity was about 70%. This morning it's 45%.

We have a drafty house, too. Lots of old, leaky windows and one of our doors has a gap you can see through on one edge. Letting the drafts bring in dry air works, but over the course of a few days, and only when it's quite cold.  For me, that means... 14F.  At higher temperatures, like you have, there just isn't enough difference in humidity between inside and outside air. That's how it works for us, at least.

David Baillie wrote:I would say a dehumidifier is certainly in order. I've found the compressor types far more common and less pricey and in a heated building fine. They do heat your space a little as well.

We have both types. In the unheated parts of the house - typically about 12 degrees C - the desiccant one is much more productive.

I found this little snippet about efficiency of compressor types:

Compressor dehumidifiers work on the principle of moisture condensing on a cold refrigerant pipe inside the unit. As a result, compressor dehumidifiers work well in very warm conditions, but as the temperature falls so their effectiveness drops off dramatically. All compressor driven units are rated in test conditions of 80% humidity and, critically, 30 degrees centigrade temperature.

A three degree drop in temperature to 27 degrees results in up to a 50% loss of performance with Compressor units. At 21 degrees centigrade (which is room temperature) a compressor unit will tend to extract around 30% of its theoretical maximum. Below 15 degrees centigrade most compressor units extract about a tenth of their theoretical maximum and in cooler temperatures below eight degrees basic compressor units stop working as the evaporator plates ice up.

Therefore a compressor unit rated at 20 litres per day extraction will extract up to 5 litres in a normal domestic environment; a unit rated at 18 litres will extract up to 4.5 litres and a 10 litre will extract up to 2.5 litres.

Michael Cox wrote:

Pearl Sutton wrote: The main problem here in the winter tends to be TOO LOW humidity.

The windows have never condensed before. It's something in what I did differently this year. And the main thing I did differently was seal it all up when it was very humid.

It does sound very strange then.

Yes, incredibly strange. That's why I think it was how wet it was when sealed up. I think it has been dry before I got around to it before. We have had a messed up fall here, and I covered the worst windows very early, as we hit freezing record breakingly early in the year.

Can you get your hands on a humidity monitor, and actually get a measure of the humidity in different parts of the house?

Very very doubtful I can get one. It's sparks on the cat dry, through it all. Does that count as a technical reading? :D

I think you mentioned earlier that you are not heating these rooms, but are heating others? Warm air holds a lot more moisture than cold air. As warm air moves around the house and cools, it actually increases the % humidity. So you may have low humidity in the heated living spaces, but dam issues in the cooler rooms.

Oh, no, these are all heated spaces. And the heat pump is drying them out hard.

Jan White wrote:
The key to venting humid air is you need to get the air in the house as warm as you can BEFORE venting. Then the air has picked up more moisture from all your stuff - windows, curtains, furniture, etc. If your house is cold to begin with, all that moisture is still just sitting there in your house.

We just did some venting cause I had to air dry a bunch of drapes inside and it got quite humid. Got the temperature up above 30°, which, let's see, is 86° in your world. It's, hmmm...5F outside here right now. Perfect venting conditions, since the air will be nice and dry. I opened a window upstairs, then went and opened a door downstairs on the opposite side of the house. In our tiny space, I only left things open for about ten minutes. Then I closed everything up and ripped the stove to warm it up again. Didn't take long since the mass in the house was all still warm.

Yesterday morning before I did this, humidity was about 70%. This morning it's 45%.

That's a really obvious and sensible process, thanks. And that one fairly quick air change can carry a lot of moisture out pretty quickly.

In our experience the best method for eliminating window condensation in the winter is exterior shutters. The next best method is bubblewrap installed on the glass on the interior surface. The glass only needs to be misted with water for the bubble wrap to adhere. We use the bubble wrap on windows that have exterior shutters so that during the day when the shutters are open to allow sunlight in we still have some extra insulation on the glass. If you can get it the bubblewrap that has extra large bubbles (1") works best. In the spring you can peel them off the glass very easily and roll them up to store until next winter.

Doug and Stacy used calcium cloride ice melter as a dessicant in their crawl space. Put what looked to me like 5 - 10 pounds in a pillowcase, (she didn't weigh it.) tied shut with a rope so that it hangs with one corner a little lower. Put a bucket under that corner. She says it'll absorb humidity until it drips out. Empty the bucket where it won't evaporate back into the house. (Calcium cloride is a salt, some will dissolve into the water. It's used in food and medicine, a lot of folks would pour it down the drain. This being a community that's careful about such things, I'm pointing it out for folks to make informed decisions. Maybe it could be evaporated on an outdoor heat source, and the residual salt returned to the pillowcase?)

By shopping around you may easily beat this price, but with just a quick search, I found 50 pounds at lowe's for $21.48.

I looked up the effectiveness of calcium chloride.

1kg of crystals will absorb 3kg of water.

My dehumidifier was getting about 6 litres per day, when the humidity was really high.

Gives you a bit of a benchmark. The downside of something like calcium chloride is that it doesn’t have inbuilt fans to circulate the air, so I suspect it would be quite slow. I believe it is good at tight spaces, like in damp cupboards.

I just got back from a shopping trip. I think walmart had calcium chloride 20 pounds for $5.something.

The buck and a quarter tree (formerly dollar tree; their prices changed) had little tubs of it:

Did you manage to get this sorted?

Possibly. We are still below freezing, I have only opened up the covers over 2 of the windows so far (and closed them back up again) Both were foggy, but not dripping. When this finishes, it is supposed to warm up to the 50s. The cold has driven the humidity to close to zero (the air freezes out the moisture) and I'll open them all up and blow them out hard again.

For what it's worth, my covers etc on the windows are working excellently! We haven't been anywhere NEAR as cold in the house as last year. The heater hasn't run as much either.

Update: Looks like they are all dried out. I'm about to mold treat the wood sills that got moldy.

So, for future reference: Do not seal them up on a high humidity day!! Even if the snow is coming in that night....

:D

Thank you, everyone who helped!!  This was seriously puzzling.

T Melville wrote:

Doug and Stacy used calcium cloride ice melter as a dessicant in their crawl space. Put what looked to me like 5 - 10 pounds in a pillowcase, (she didn't weigh it.) tied shut with a rope so that it hangs with one corner a little lower. Put a bucket under that corner. She says it'll absorb humidity until it drips out. Empty the bucket where it won't evaporate back into the house. (Calcium cloride is a salt, some will dissolve into the water. It's used in food and medicine, a lot of folks would pour it down the drain. This being a community that's careful about such things, I'm pointing it out for folks to make informed decisions. Maybe it could be evaporated on an outdoor heat source, and the residual salt returned to the pillowcase?)

By shopping around you may easily beat this price, but with just a quick search, I found 50 pounds at lowe's for $21.48.

Bumping this thought, I'm in Missouri, today is March 24, Ice Melt stuff is on sale right now, and going to be unavailable soon. If you want it for dehumidification this summer, buy it NOW!!!
:D

And I had a thought about my crawl space moisture problems at this rental. Several years ago I got the landlord to pay guys to do black plastic on the ground of the crawlspace (worst job I've ever seen, but that's not the point) AND pay an electrician to run a sump pump down there.
I'm going to hang the calcium chloride over the sump pump catch basin, so the water drip off the calcium is removed by the sump pump. If this is a bad idea, please tell me!!

Data points: The crawl space is very close to inaccessible, extremely difficult to get in and out, I cannot empty buckets from there. I can go down there once and set up a system so I can refill a drip bag from the access point (probably a swinging arm with a rope to move it into both positions) but that is all. The crawl space is the main mold source of this house. And it's a rental, there's a limit to what I can or will do to it.

HEy just share my experience.... I have the same problems.

I swear there is a difference between the dollar store stuff and the the name brand "Damp Rid" ones. My Damprid buckets fill up faster I swear.

New windows coming in 2023! Hopefully...