# Condensation on Bedroom Windows



## virgo08

I have excessive condensation on my bedroom windows on cold frosty mornings.  This is causing mould on my blinds and curtains and also the bedroom wall.  I have wallpaper on one Wall (Over the bed) the corner wall has black mould forming and also around the skirting.  I have the heat on in the evening and it goes off while we are in bed and comes on again in the morning.  My windows are double glazed and its a bay window with a lead cover on top where the windows sits out from the tiled roof.  The house is 10 years old, there is a vent in the room but i close this as its over my head. What would be causing this and how can i prevent it?


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## eddie7

i would say the vent is there for a reason so it shouldent really be closed,bedrooms with no ventilation usally are prone to getting condensation on the windows


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## Welfarite

Ventilation is important and having the vent closed is probably not helping. This any use?


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## Celtwytch

Another simple solution is to open the window for as long as possible each morning, to allow the window to dry.  Or sleep with a window open a little, if that's feasible.  When I first moved into my house there was a lot of mould around the bedroom window, and on the blinds.  Since cleaning that off, and following my own suggestions, it hasn't returned.


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## eddie7

you can also get whats called a trickle vent, its an aftermarket product that can be fitted to the window frame, do a google on it


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## redriddick

Have the same problem but not as bad.Could be all the action!!


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## hopalong

you could get a dehumidifier,it takes away moisture from the air.


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## Smashbox

I got a dehumidifier last month as I wasn't able to open the windows in the room very much and condensation was always there, leading to mould - it was really awful. 

I now run the dehumidifier in a spare bedroom and there hasn't been a bit of condensation after the first 2 days or so. This is the same for all windows and doors. My front door used to be 'too airtight' (Thats what I was told) and the water used to run off it. Now, all windows and doors are condensation - and mould - free.

Very happy with it


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## 10to1

Hi Smashbox. What model of dehumidifier did you get? Does the sound not keep you awake?


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## eamonn123456

dehumidifier is a great job if you are unable to remove / reduce the source of the extra humidity (cooking, showering, baths, washing up, kettle, people, pets, drying clothes indoors), or ventilate the excess humidity in any other way (wall or trickle vents, extractors, open windows).

drying clothes on a clothes horse is a big culprit. 

Be careful that mould is not building up behind furniture or boxes.


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## eamonn123456

PS could also be caused by damp penetration


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## Willowchase

10to1 said:


> Hi Smashbox.  Does the sound not keep you awake?



Does the cost of the electricity used not keep you awake.


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## eamonn123456

I think its cheaper to run a dehumidifer for a couple of hours than to have too much heat loss thru excessive ventilation, but i may be wrong.


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## Willowchase

eamonn123456 said:


> I think its cheaper to run a dehumidifer for a couple of hours than to have too much heat loss thru excessive ventilation, but i may be wrong.



Ah but the problem here seems to be too little ventilation and not too much.


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## eamonn123456

sorry, I was unclear.

I mean that using a dehumidifier as a solution, as opposed to throwing open the windows for extended periods (excessive ventilation) as a solution, may be cheaper.


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## Willowchase

eamonn123456 said:


> sorry, I was unclear.
> 
> I mean that using a dehumidifier as a solution, as opposed to throwing open the windows for extended periods (excessive ventilation) as a solution, may be cheaper.



Sorry I'm with you now.


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## LindaL

Any advice/opinions on this...

ALL of our windows (in a 2-year-old new build) are almost 50% covered with insulation every morning now since the cold snap, upstairs and down.  We had all sorts of problems with the inferior company that supplied the windows but I believe they're all fixed now, i.e. the windows are airtight.  They all have trickle vents (no room vents) but these are all open and don't seem to make any difference.  

We don't have a lot of heat on overnight and it tends to disappear quickly anyway - house is very spread out and cheaply insulated.

Is our house too airtight?  Or what else could be causing these sheets of moisture on our windows every morning? (which persist throughout half the day, incidentally)

Thanks!

LL


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## tosullivan

some moulds are very dangerous and can kill....ventilation is the key to keeping mould at bay


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## spillac

Hi, 

I have the same problems in my sitting rom and bedroom. can you tell me the make of dehumidifier you bought or if anyone knows of a good one/ how much etc?


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## wexford dude

Virgo08,

You could try a Passivent.These vents fit into existing wall vents - something like a Fresh 99H may be of help.I have not used them but they claim to reduce the humidity in rooms thus reducing condensation.Unfortunately they are expensive buggers.
The only problem I would see with a dehumidifier is that as it draws alot of the moisture from the air it may lead to dry coughs - am only speculating cannot say if this would actually happen.I only know that when the little one has a dry cough a good solution is to put a humidifier in her room for 1 - 2 nights and it's gone.
I suppose you could argue that the Passivent would do the same thing but it may be worth investigating.


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## Smashbox

Sorry, I missed this.

Its a Delonghi (I can't spell the name of it)

Low noise so its not a problem, although its running in a spare bedroom right now. It costs about 3c an hour to run. I'd prefer to pay that than kill myself with mould and mildew.

Cost €149 in Argos. I got it in the North and was about €120 there.


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## PaddyH

Hi wexford_dude,

Are Passivent vents available in hardware shops in Ireland? Can't find anywhere to buy them online - they look very good on their website


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## wexford dude

Hi PaddyH,

The suppliers in Ireland are Richmond group in Rathcoole.Don't have the number on me but a quick google should do it.
Again unfortunately they are expensive buggers.

Best of luck
Wex Dude


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## spillac

thanks a mill, will look into both of them.


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## Eoin99

Mould can only grow when relative humidity is above 60%. N one wants open air vents or windows in winter but this really is the answer. Air as much as you can to reduce moisture levels.

With such widespread mould, you'll have trouble controlling it now. Prevention is better than cure but the infestation needs curing. Call in a mould professional - there are some in Ireland. Remeber, while live mould is growing in your home, its filling the air with spores...not good!


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## PaddyH

Just to show the power of opening windows. This morning after getting up and showers etc our bedroom had a humidity level of 69%. I have tilt and turn windows and opened the bedroom window fully for 2 mins - Bit windy and cold ourside so plenty fresh air came in! Within those 2 mins the humidity level dropped to 48%. 

Last week I also fitting a Fresh Air Trickle Vent - http://www.freshairtricklevent.com/ - bought for €18 from Canada - extremely easy to fit. Benefit of this vent is it can be made AIR TIGHT if necessary - So you can have ventilation when you want and also prevent heat loss at other times by closing vent completely.


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## BarneyMc

This looks good Paddy H but do you have to drill a hole into your wall and if so then how do you make sure this device fits tightly and there is no air leakage through the new hole?


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## PaddyH

Hi BarneyMc,

I replaced a regular slide vent which leave in alot of cold air especially if vent is exposed to wind etc - also they leave in alot of noise. So there was a 4 inch hole (sewage pipe) already in the wall and the trickle vent fits perfectly and when fitted it completely closes the gap between the vent and the wall. You can then twist the vent anti-clockwise to allow air to circulate or twist clockwise to make air tight. When air tight it prevents more noise also. We have trouble with neighbours dogs barking and it helps alot.


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## BarneyMc

Hi PaddyH,

That sounds good. So it fits a 4 inch diameter round hole?

I have old rectangular wall vents that have been blocked off (I know this shouldn't have been done but I suppose it shows how draughty and non-air tight wall vents can be).

Does anyone think it would be worthwhile to fit these devices (€18 each) to all the old wall vents in my house and also will this be noted when I go to sell the house (BER rating)?


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## PaddyH

Hi BarneyMc,

Yes the fit perfectly in a 4 inch diameter hole.

I did the same myself before - filled it up with expanding foam - But you need ventilation and I regretted closed the vent. I think these vents are a happy medium - they will allow ventilation when you want it and allow you to close them airtight if you want also. 

You can contact the company and they might do a better deal than €18 each if buying more than 1 - less shipping costs etc. I found them excellent to deal with - it did take about a month to arrive but they replied promptly to all my emails etc.


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## Jus

Try using bleach to remove the mould. That's what they use on "How clean is your house". Mould on walls can be from lack of insulation too. I had this problem in a corner of my ensuite. I cut out a hole in the plasterboard to discover there was no insulation here. I also have mould  around my windows in the back of the house. The ensuite and bedroom, both north facing which would make them colder rooms. Yet to investigate. None of the vents are done properly either. A hole knocked out of the wall and the vent covers stuck on (barely). This made the house cold very quickly as the wind blew in through the walls. I can even see cobwebs blowing out from behind a socket !! I've fixed the one in the sitting room but it allows alot more noise thru now cos is straight as opposed to having to pass over a block in the window bay roof space before getting to the other side.
Houses built during the boom tend to suck.


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## mad m

PaddyH, I went to buy one of these and it was working out at $39+$12 shipping. That's more than €18...?


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## AlbacoreA

eddie7 said:


> i would say the vent is there for a reason so it shouldent really be closed,bedrooms with no ventilation usally are prone to getting condensation on the windows


 
In my experience most of those vent fitted by builders are not air tight and even when closed theres a draught from them. I doubt closing is going to have that much effect of condensation. The probably some other problem that need resolving.


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## PaddyH

Hi Mad M,

Yes I see it's 51.95 USD. I got charged $29.95 CAD - I'm not sure if there is a different way into the site where a different currency might be shown. It's worth emailing them and ask what's the best price they can do it for. 

AlbacoraA. I'm sure you could block the vent fully - BUT if you do so you need to open the windows ALOT more and most people aren't around the house during the day (those that still have jobs thankfully anyway!) to open windows - Hence when vents are very important. You MUST have some ventilation.


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## AlbacoreA

PaddyH said:


> ....
> AlbacoraA. I'm sure you could block the vent fully - BUT if you do so you need to open the windows ALOT more and most people aren't around the house during the day (those that still have jobs thankfully anyway!) to open windows - Hence when vents are very important. You MUST have some ventilation.



I just making the point that most standard vents are far from airtight even when closed. I'm not suggesting blocking them fully. My own let a force 10 gale through. I'll be installing better vents that have baffles to stop wind coming straight through.  I'll also be sealing around the vent so that air can't get into the wall space. 

Personally I think the standard vents that are installed in most houses are a joke.


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## PaddyH

I agree completely - If the standard vent is exposed to wind etc - they are a joke. I must say that the Fresh Air Trickle Vent (that cost me €18) does close air tight and can be fitted in 5 mins - so for me I get the best of both worlds.


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## AlbacoreA

I'd say you wouldn't have to close a trickle vent or similar. Once the bulk of the draught is eliminated.

Theres more here...
[broken link removed]
[broken link removed]


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## gerpug

Celtwytch said:


> open the window for as long as possible each morning, to allow the window to dry. Or sleep with a window open a little


 
I too have condensation on my windows everyday. There's so much that the windowsill is soaking!! Ive noticed some damp spots on the walls too. Whether its from the condensation or not, i dont know. Ive tried the above suggestions with no improvement. anyone have any idea on what i can do now?


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## Smashbox

I have a dehumidifyer running and it takes all my condensation away


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## NHG

It just goes to show the problems that arise when a house is too airtight.


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## Smashbox

Yep, I had water running off my front door and into my hall it was that bad. All the windows had water on them every morning, as did my back door too.

Was told that the doors were too airtight, nothing I could do. Opening windows helped a little but the dehumidifyer was the best, I even recommended it to my neighbour and she uses one now too


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## rrrrrrrrrr

Keep a J cloth handy upstairs and give the bedroom windows a quick wipe in the morning and open them for 5 or 10 min.

I know it's not ideal but it will save your curtains and paintwork and health!


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## Smashbox

I tried all that too


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## PolishWindow

Condensation effect occured when are combined three factors heigh humidity ,cold surface of glass or wall and too heigh/or too low room temperature. 
For keeping low humidity level we should use tricle vents , often openning window or dehumidification. 
Importent is using Low E glass U=1,1, insted ordinary glazing U=2,8W/Km2 .Also timber or uPVC windows have "warmer" frame then aluminium.Sometimes people have not thermally broken aluminium door/window, it will always casue condesation. 
Another cause for "cold" wall is bad insulation (or no insulation ) between wall and windows frame.


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## smallclough

I've posted elsewhere about this - but the following link will both help to diagnose, and hoefully give you all the fixes you need to solve the problem:

http://www.heritage-house.org/condensation.html

Hope this helps!
Pete


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## extopia

Forget about using a dehumidifier. If it helps, it's only telling you that your ventilation isn't working the way it should.


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## selfbuild09

It may not be possible but why not look into blocking the original vent permanently and installing a new vent on the opposite side of the room. I'm assuming though that you have two external walls in your room.  It could be the same as last vent but make sure it's surface area is at least 3,500mm Sq though...min imum regs nowdays.

Another person made a good point though, it could be damp penetration. Do you have black stains on the walls near the floor?


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