Anything I can do about bad window condensation?

Soldato
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England
Moved into our (rented) house in May.
Now the weather has changed we’re getting pretty bad window condensation every morning.

The downstairs windows just have it in the corners and a little along the bottom edge.

The upstairs windows are pretty bad, it’s literally dripping off my 16month old daughters windows.

They’re double glazed, and we have the little ‘window vent’ open at the top of the window. It’s an older house with air vents in the corner of the rooms. I’ve also got these open.

I wouldn’t say this is a particularly cold house, just seems mega humid and I’m worried about mould starting!

Anything we can do to reduce it? I’ve ordered some of those little plastic ‘moisture absorbent’ boxes but that’s just a temporary measure.

Any hints/tips?
 
Bedrooms always suffer the worst as the human body can put out a surprising amount of moisture when sleeping.

A dehumidifier would be your best bet (as in a proper unit, not the passive boxes you refer to).
 
Bedrooms always suffer the worst as the human body can put out a surprising amount of moisture when sleeping.

A dehumidifier would be your best bet (as in a proper unit, not the passive boxes you refer to).
Yeh we have a small one actually, this: Pro Breeze Dehumidifier 1500ml Portable Air Dehumidifier for Damp, Mould, Moisture in Home, Kitchen, Bedroom, Caravan, Office, Garage, Bathroom, Basement https://amzn.eu/d/40M7pZN

I was just concerned about the cost of running it as our electric prices have gone sky high since I first got it! Where would you put it?

Edit: oh it would only be about 1p per hour to run. Wouldn’t want it running overnight in the baby’s room though
 
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Without knowing the layout of your upstairs it's hard to say however, if it's the traditional landing area with bedrooms off of this, I would stick it on the landing and keep all the bedroom doors open to allow the unit to pull in moisture from all rooms.
 
If using a dehumidifier then you should get a humidity meter (or a couple as cheaper ones can be unreliable) and check the humidity level as its easy to reduce the level too much which affects health and breathing. Many dehumidifiers won't go below certain levels but this is often still too low for comfort.

Drying washing indoors can also increase humidity significantly. I can see this from our airing cupboard humidity sensor whenever washing is put in, it's such an big increase and then drop as the clothes dry I've automated it to notify us the clothes are dry.
 
We had a similar issue after we moved into our house a few years ago however last year it was particularly bad to the point where the bedroom window was full of water droplets!

As others have said, get a decent dehumidifier. We got a condensing one however with it getting colder a "deiscant" one is probably better since it doesn't cool the air in order to extract the moisture from it.

Other bit is make sure your air-flow in your house is decent, it's difficult when it is getting colder but making sure there is a ventilation pathway is a good way to avoid one room being much worse than the others, I know at my dads we installed a vent which pulled air out of the loft into the rest of the rooms which helped his condensation issues a tonne. Likewise if you can (And your windows have it) keeping the mini vent open whilst making the room cooler will help exhaust some of the warm damp air outside.

Avoid drying clothes inside, don't leave water in the sink, keep the bathroom door closed after showering/bathing/damp towels and don't waste too much money on the mini damp extractors, from personal experience whilst they did help it wasn't a massive improvement.

Also, check the plants in the room, we moved our Yukka out of the bedroom and noticed there was a heck of a lot less moisture on the windows on a mornings.

A last bit which isn't reducing it but makes it more bearable, Karcher Window Vacs, we used to do ours on a morning and on a weekend would go round with anti-mould spray to avoid any nasties in the rubber seals
 
... plants - yes, that's an interesting contributor.

maybe get a humidity monitor to get some data - parents got one for a living room £10-£20 can't remember if it keeps the max, maybe you can get logging(to app) ones now, at reasonable prices.

as said, making sure bathroom/cooking is not contributing unduly, and evacuating moisture after showers, is important; our kitchen window always open a couple of inches.
 
I have a humidly monitor.

Downstairs it was 18.9c 51%humidity
Left it upstairs for an hour, 17.4c 60% humidity at 1230pm.

Always keep bathroom door shut with windows open a couple inches and extractor fan on.

Ordered one of those karcher window vac things to help out! I really don’t need a mould problem

This is the 6th house I’ve lived in and never had windows do this before.
 
You will probably find the windows are at least 10 yrs old - all mine except two front windows are 12 yrs old and front 2 yrs old -The front are condensation free but rest have moisture n them.
I put it down to older windows are not as good as todays.
 
You will probably find the windows are at least 10 yrs old - all mine except two front windows are 12 yrs old and front 2 yrs old -The front are condensation free but rest have moisture n them.
I put it down to older windows are not as good as todays.
Yeh, although double glazed the windows does seem a bit...naff! Annoyingly there isn't anything I can do about that.
 
Moved into our (rented) house in May.
Now the weather has changed we’re getting pretty bad window condensation every morning.

The downstairs windows just have it in the corners and a little along the bottom edge.

The upstairs windows are pretty bad, it’s literally dripping off my 16month old daughters windows.

This is normal and is caused by the water vapour created by exhaled breath. The extent of the mould problem you would get is the rubber seals around the window panes could get mouldy. However, this can be easily avoided by wiping down the windows each morning to dry them, or get a Karcher window vac if you want. It is not indicative of a potentially bigger mould problem.

Obviously the problem is caused by humid air coming into contact with the cold surface of the glass. If you really wanted to stop the water forming, you could investigate ways of keeping the internal glass warmer. For instance, if you blutacked those clear A4 document holders to the window, water would not form, because the plastic is warmer than glass (not saying you should though). If you had an internal blind next to the window, it could also reduce the problem, keeping the glass warmer and preventing the humid air contacting the glass.
 
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had this in the house I grew up in, mum would go round the windows every morning with a cloth to soak the water up and squeeze it into a plastic jug, didn't seem to be a fundamental problem, just a little hassle.
 
Definitely get a humidity sensor, you don't need anything fancy or expensive.

I was going to suggest leaving the windows on lock (in the locked and slightly open position), but you already have your vents open. Maybe you could experiment with the vents and slightly open window and see which gives better results - bearing in mind that you'll probably have to give in to complaints and close the window at some point as the weather gets colder.

I used to have a dehumidifier, but they are expensive and noisy to run. I found I got better results by just opening the windows for an hour each morning (or all day if possible), even if the windows aren't fully open.

The godsend for me was buying a Karcher window vac to get the condensation off the windows in the morning.
 
I have a humidly monitor.

Downstairs it was 18.9c 51%humidity
Left it upstairs for an hour, 17.4c 60% humidity at 1230pm.

I've just checked the logs for the 6 sensors we have dotted around in my HA dashboard and for the last few days we've been in the 40 to 60% range (other than airing cupboard which is 30 to 70%) so that range isn't too assuming it doesn't get worse at night. The sensors I use are fairly cheap Zigbee ones but are close to a calibrated one I have so should be accurate, however we don't have any significant condensation on windows other than after showering until the extractors get on top of it.

How are the windows in general for condition, what is the glazing gap size, any fogging and are there any drafts around the edges of openers and the frame itself?

We had our windows changed and I did all the internal making good as gaps around windows under trim which can almost lead to the outside as well as the cavity is very common with the 'professional' installations I've had in previous homes. I've seen more condensation on poorly fitted ones in previous homes where I assume the inner side is cooler than it should be due to this as well as with thinner air gaps in older glazing panels.
 
Moved into our (rented) house in May.
Now the weather has changed we’re getting pretty bad window condensation every morning.

The downstairs windows just have it in the corners and a little along the bottom edge.

The upstairs windows are pretty bad, it’s literally dripping off my 16month old daughters windows.

They’re double glazed, and we have the little ‘window vent’ open at the top of the window. It’s an older house with air vents in the corner of the rooms. I’ve also got these open.

I wouldn’t say this is a particularly cold house, just seems mega humid and I’m worried about mould starting!

Anything we can do to reduce it? I’ve ordered some of those little plastic ‘moisture absorbent’ boxes but that’s just a temporary measure.

Any hints/tips?

If you don't have the heating up high enough to evaporate condensation, then the solution is counter-intuitive. You have to let more cold air in and (importantly) out.
The problem is entirely down to warm, condensation laden air has nowhere to go, it has to be allowed to leave the house.
 
I was going to suggest leaving the windows on lock (in the locked and slightly open position)

that's the other problem with modern upvc widows inability to leave ajar without them blowing open, over night, even on 2nd floor, where you don't have security issue,
old windows, obviously had a stay, but nothing incorporated in modern day handles to do that;
(folks had some bungalow upvc replaced to put in secure small opening panels at top, too)
 
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