R/H and condensation

[CaptainQuintero]

Now this is something that the brains trust of FoH should be able to figure out.

Why the heck do my bedroom windows have condensation on them in the mornings when the weather is cold out? 

Or more importantly how do I stop it?

I'm guessing it's something to do with the air in the room with people sleeping in it has a high r/h due to exhaled air being full of water vapour and that hitting the cold windows and then something to do with dew points? The fact it doesn't happen in summer when you have your windows open and it's warm at night points me to that anyway.

I've been trying a number of things; keeping the windows in said room open sightly during the night and having the heating on through the night, low temp and high temp etc buy it's still not doing much.

I'm guessing piggy has zero condensation on his windows in the morning

Can we solve this once and for all?

*Something something behike something on topic something ring gauge too large*

[scap99]

You stop it by upgrading to a double pane or even triple pane window.

Why does the mirror fog in the bathroom?

Why does a beer can sweat?

Same concept, just different temps from the observation standpoint.

[CaptainQuintero]

2 hours ago, scap99 said:

You stop it by upgrading to a double pane or even triple pane window.

Why does the mirror fog in the bathroom?

Why does a beer can sweat?

Same concept, just different temps from the observation standpoint.

Already have double glazing so that can't be the solution.

Like steam on a kitchen window when boiling pasta etc you get it to go by opening the window. Obviously you can't sleep with the windows full open during winter, so maybe it's a case of finding how much you can open it without it making the room too cold?

[Colt45]

Wipe off and enjoy  

[Fugu]

Do you get this already now, with outside temps still well > zero °C, CQ?!

Question: Do you turn the temperature lower in the sleeping room (with night setback perhaps)? And do you perhaps keep the door open, while other rooms are being heated?

Other question: How "active" are you during the night ....

[scap99]

41 minutes ago, CaptainQuintero said:

Already have double glazing so that can't be the solution.

Like steam on a kitchen window when boiling pasta etc you get it to go by opening the window. Obviously you can't sleep with the windows full open during winter, so maybe it's a case of finding how much you can open it without it making the room too cold?

The double pane window shouldn't sweat unless you have lost the argon charge between the panes.  Another thing could be that your weather stripping is failing and allowing cold air to infiltrate.  If that's the case it could be chilling the interior glass pane.

 

[CaptainQuintero]

1 hour ago, Fugu said:

Do you get this already now, with outside temps still well > zero °C, CQ?!

Question: Do you turn the temperature lower in the sleeping room (with night setback perhaps)? And do you perhaps keep the door open, while other rooms are being heated?

Other question: How "active" are you during the night ....

I've just started noticing it this past week or so, like you say its no where near true winter weather yet.

The house is set between 20-21c across all rooms and I keep all the internal doors closed all the time, the heating is set to kick on and keep that temp regardless of day or night if the house temp drops.

Windows and seals are all relatively new

Activity wise, that's more of a daytime activity

One thing I have noticed is that the bedroom is noticeable cooler, there is an air brick located high up on one wall. I've never seen this type before (we've just moved in). Normally they are in the outside brickwork and open into the cavity. This one leads right through the wall right into the room with a siding shutter. I've assumed that this would be a good thing, that ventilation helps prevent a build up of condensation in a room which can lead to mould.

Maybe this could be the issue?

[Fugu]

Hmm, sounds all good so far. I don't think the ventilation brick should be an issue, since, as you say it should act in removing humidity, as the gradient during the colder season is directed from inside --> outside.

The cause for such condensation often is not straightforward and tricky to analyse without actually being on site. If you say windows and seals are relativly new, that tells me there is not much leaking of air right now. But what I would not consider as an ideal solution would be keeping the windows ajar during the night in winter, as you don't want to pay extra for heating your environment.

Often it is less the glazing itself but the window framing being the cause, representing a thermal bridge (with condensation usually occurring first/mainly in the less ventilated and coldest lower corners of the window). And the effect can be boosted if the external walls come with extra insulation, where the window represents the coldest surface in the room (which actually is not the badest thing, as you'd prefer water condensation on the glass, which you can easily wipe off in the morning, than invisibly settling on the walls where you'll get mould).

Usually, this effect is stronger at the start of the cold season (as I got it, you are @ northern UK, so outside temp about 5 - to 8 °C in the night, I guess?), which is obviously why you notice it now, since the house still holds a lot of moisture from the summer. Which is then steadily becoming less during the heating period, and with the humidity (abs.) of the outside air dropping. What you perhaps should do is a few good ventilations of the room during the day (for just a few minutes, with windows fully opened) and a final one directly prior to going to bed. Just to exchange the air, but not letting the room cool out too much (but which is obviously what you already do, keeping the bedroom > 20°C). Other than that, you could of course use some technical solution with an air dehumidifier for the time being. Perhaps the issue will settle a bit when further into the winter.

[CaptainQuintero]

Yeah that's what I was thinking; ventilation must always help, it has to.

The windows are going to be the coldest surface at night so condensation is always going to form on them if the room has a high rh (breathing at night) 

Thinking logically, good ventilation and keeping the room warm must help. The ventilation is already there due to the room being cooler.

So possibly keep all upstairs doors open to increase airflow and get warmer air in and circulating?

The room is roughly 19c and 71%rh so like you say it seems to not be a significant issue probably down to the changing of seasons

 

[stevem]

My parents had this issue when they moved out to Vancouver Island. Their windows were always damp in the morning so a friend of theirs recommended putting some Damp Rid (Found at Walmart) in a small dish on their window sil and this product seems to work for them. While not eliminating the reason why you are experiencing condensation in the first place, if you are looking for a product that will help you out in the short term while you determine what you can correct, I would suggest you give this a try.

[Fugu]

24 minutes ago, CaptainQuintero said:

So possibly keep all upstairs doors open to increase airflow and get warmer air in and circulating?

No, that's actually what you should avoid! With ventilation I meant ventilation to the outside, as the outside air is much dryer in wintertime - even if it's a rainy day! If you'd let warmer air from other rooms in, it carries more moisture with it that would then add to the moisture and will worsen the condensation effects in your bedroom. That's why I asked whether you are keeping the bedroom door closed. Never "heat" the room passively by letting warmer air from other rooms in! Best would be letting no temperature gradient build up between different rooms. If your bedroom is upstairs that deepens the effect, as humid air rises up within the building (it's all the same effects, quite as in your humidor, actually...)

24 minutes ago, CaptainQuintero said:

The room is roughly 19c and 71%rh

Yep, that's actually quite humid. Dewpoint for that combo is 13.6 °C. So once your inner glass surface falls below that, you get condensation.

You can't stop breathing during the night obviously, but what you can do, is bring the 'start'-humidity a bit further down.

[scap99]

38 minutes ago, CaptainQuintero said:

Yeah that's what I was thinking; ventilation must always help, it has to.

The windows are going to be the coldest surface at night so condensation is always going to form on them if the room has a high rh (breathing at night) 

Thinking logically, good ventilation and keeping the room warm must help. The ventilation is already there due to the room being cooler.

So possibly keep all upstairs doors open to increase airflow and get warmer air in and circulating?

The room is roughly 19c and 71%rh so like you say it seems to not be a significant issue probably down to the changing of seasons

 

Yowza, 71% sounds absolutely miserable for indoors.

I'm so used to living with only two seasons...hot then cold. If the AC isn't dehumidifying, then the furnace is running.

 

 

[Bohn007]

Do you have a humidifier attached to the furnace? You might have it turned up too high

[LGC]

A large temperature differential between ambient air and surface produces condensation. Find a dew point calculator online, if you don't like using graphs. With higher ambient temps, the potential moisture content of the air can be higher. Simply put, you must maintain a surface glass temperature that is higher than the dew point temp (which is a function of your RH% and ambient temp). Your options are getting better windows, using a dehumidifier, or constantly blowing warm air on your window panes.

[CaptainQuintero]

Hmm I wonder if the old hygrometer I grabbed out if the drawer is off, it certainly doesn't feel humid and I've no damp issues anywhere, or condensation issues anywhere else

I bumped the heating up a degree about an hour ago (the gf is asleep) and the inch or so of condensation on the bedroom windows has gone now, so I'm guessing it's going to be a case of trial an error. I've cracked the bedroom windows open sightly to help with the room vent already

The windows have never been running with water, just misted in the morning, enough to be wiped off with a handkerchief. It is just something I wouldn't want to get worse

[CaptainQuintero]

34 minutes ago, Bohn007 said:

Do you have a humidifier attached to the furnace? You might have it turned up too high

Nope not as far I know (I didn't even know that existed ) just a standard combi boiler with radio controlled thermostat. 

[CaptainQuintero]

24 minutes ago, Brandon said:

A large temperature differential between ambient air and surface produces condensation. Find a dew point calculator online, if you don't like using graphs. With higher ambient temps, the potential moisture content of the air can be higher. Simply put, you must maintain a surface glass temperature that is higher than the dew point temp (which is a function of your RH% and ambient temp). Your options are getting better windows, using a dehumidifier, or constantly blowing warm air on your window panes.

I think ironically a lot of the newer windows here seem to create issues. Old drafty ones had enough ventilation to keep condensation down, they've on the whole been replaced with 2 or 3 pane ones and sealed in without any thought for air flow.

A lot of houses here were given free (or virtually free) cavity wall insulation a few years back by the government.

Everything is sealed up like a drum

[scap99]

13 minutes ago, CaptainQuintero said:

I think ironically a lot of the newer windows here seem to create issues. Old drafty ones had enough ventilation to keep condensation down, they've on the whole been replaced with 2 or 3 pane ones and sealed in without any thought for air flow.

A lot of houses here were given free (or virtually free) cavity wall insulation a few years back by the government.

Everything is sealed up like a drum

To follow up on that Indoor Air Quality (IAQ) is a huge topic in the hvacr industry.  New construction with these tight building envelopes truly need fresh air intake and stale air exhaust incorporated into the climate control system.

 

 

[LGC]

I agree that a tightly sealed space with very minimal air exchange with the outside environment is not good for air quality. The ideal HVAC system will have no unwanted air infiltration... with air intake and discharge being controlled, monitored, and conditioned (inlet). When doing half day trips in the work van, I have to open the window every so often... especially in the winter.

[PigFish]

Do you sleep with the door closed in your bedroom? (at night)

Do you have a 'formal' master bedroom? Meaning is there a 'mater bathroom' attached?

My guess is that you might answer yes to both. Well, this is the problem!

Is there a vent fan in the bath? If yes, use it! People often close up their bath to keep the heat in when bathing, then keep all the moist air in by closing the door when they leave. My wife is famous for closing the bathroom doors. We have hoses and live on a 'dirt lot' and get a lot of dust. So she does this believing that this will halt the dust. Frankly, you should consider keeping that door open after showering/bathing, and then the bedroom door, while you are not in the room in order to diffuse the water.

Bathrooms are a main cause of interior water vapor. As you begin to close up a home for winter, the home may go over wet until the outside world gets cold and freezes at which point the outside air exchanges begin to offset this problem... If this time of year it is damp and cold, verses cold and dry, the combination of air exchanges and internally supplied water vapor is simply greater than the room can bear. Again, I am guessing, but I would say that you have an attached bath and close up rooms.

Best of luck on the problem. -Piggy

[luv2fly]

17 hours ago, scap99 said:

To follow up on that Indoor Air Quality (IAQ) is a huge topic in the hvacr industry.  New construction with these tight building envelopes truly need fresh air intake and stale air exhaust incorporated into the climate control system.

 

 

Yes.  As of Jan. 1, 2016 it is code here.  As is testing the tightness of the ductwork and building envelope.  "Build tight and ventilate right" is the phrase I heard recently.

[scap99]

8 hours ago, Brandon said:

When doing half day trips in the work van, I have to open the window every so often... especially in the winter.

That's just the beans working their magic.

[luv2fly]

Beans, beans...etc....

[LGC]

Naw, my farts don't stink. My steady diet of red meat and hard boiled eggs makes them smell like chocolate chip cookies.

[scap99]

1 hour ago, Brandon said:

Naw, my farts don't stink. My steady diet of red meat and hard boiled eggs makes them smell like chocolate chip cookies.

Boiled eggs and Budweiser.

Biological warfare.