What am I doing wrong with my windows??

[monpetitlapin]

Hi Mners I need help!

We have struggled with mould and damp for a couple of months. All advice suggested it was because we needed to open the windows more when we can and use the dehumidifier when we can't open the windows. I clean the water off the windows every day. The landlord cleaned out the guttering a few weeks ago. We don't dry washing in the house and we use the shower every 2-3 days (always with a window open). It's an 80s build the size of a Lego brick with central heating and double glazing. We keep the heating on at a low level to try and avoid big temperature fluctuations.

The dehumidifier reading suggests desert-levels of dryness, it's barely needing emptying compared to when we used it in our old Victorian farm cottage, and yet the windows are still condensing more than halfway up and we keep getting mould on the paint around the windows.

Shouldn't this all be working? What are we doing wrong?

Is that inside the house or trapped between the two panes?

Do you have thick curtains in front of the window?

Is it just that window?

What temperature is your heating on?

Is the dehumidifier sufficient for the space you are drying?

Does the sun reach those windows?

Do you have lots of plants?

Do you go out in the day or are you at home most the day?

Thanks for replying!

The water is on the inside of the windows (we do also have it trapped between two panes in one window in the front bedroom but the others are fine).

We have a thin blind covering each window.

It's all the windows but the upstairs ones seem to be the worst even though they're the most ventilated (our front living room window doesn't open).

The dehumidifier should be fine for where we're drying (see the humidity reading on it - it thinks the air is very dry and the air feels very dry on my lips and eyes).

Heating is constant at 16.

We have no plants as two toddlers.

I have no idea if the sun reaches the windows, sorry. It's link-detached and arranged in an odd diagonal with the house next door, so it's possible the sun doesn't hit the windows. Is this a potential issue?

We are all out 7:30 to 6:30pm every weekday (but there are 2 adults and 2 preschoolers in a 400ft-square house when we are in) and usually out for about 4 hours Sat and Sun.

Am off work today as ill so I'm noticing it even more than usual. I just wiped the window down after I took the last photo and it's coming back already! It is frosty outside, could that be the reason?

Do you have trickle vents? If so open them as they allow a constant flow of air round the house (you don't have the faff of opening and closing windows).

It's warm air coming into contact with the cold window. I would not be having the heating in constantly as that is making the problem worse.

Screwfix has a great guide

www.screwfix.com/guides/building/how-to-stop-condensation

Sorry, they DO advise keeping the heating on constantly! ignore me!

Maybe the dehumidifier is broken?
Or higher humidity by the window how far away is dehumidifier?

I've read that having a peace lily on the windowsill helps with condensation and mould.

Moisture vapour in the air turns to water when it hits something cold. It's simple basic physics. ie: the water vapour in your room/s is turning to water against the cold glass.

I'm not trying to be patronising by the way - i lived in a house with a terrible damp problem and the amount of do's and don't's and myths and tips made my head spin. Once i absorbed the fact that water in the air turns to droplets against something cold it was a comfort because i understood what was going on.

At one point in that house even a metal key which used to sit in the kitchen door dripped with water because it had got so cold in the night!

The humidifier is either giving out the wrong reading, or is in a place in the room which IS dry, but for some reason the air around your windows is damp. Are your windows sealed properly? Are you drying washing on radiators near the windows?

Some of my older windows (shit 1980s double glazing) are prone to condensation. Be sure to open the window overnight (just a crack) of any room that you sleep in. That improves matters, but some water is inevitable if the window surface is cold. Just quickly wipe it off every morning.

Yes, i agree with pp - if the double glazing is shit (leaking even a tiny bit of air) the little gap between the panes of glass (which is designed to allow the internal pane to be warmer than the external one) is not able to do it's job.

Even with the heating on, the inside panes of your windows are as cold to the touch as the outside are, and so even vapour from you breathing will turn to water when it touches the glass.

Ahhh thank you (and @Laiste)! This explains it! Yes the landlord hasn't even replaced the kitchen and bathroom since the house was built in the 80s, we have amazingly shit vinyl floor in the bathroom with an 80s flecked pattern on it. We keep the windows closed overnight as we're by a main road but maybe we need to at least keep them open into the evening. I'm currently closing them when I come home every night.

I'll just try to suck it up then and keep fighting the mould as we're waiting for anything in our area to come on the market so we can buy something. Hopefully we'll be out of here before next winter!

We have decent double glazing but still get some condensation on the windows at times - as a previous poster has said, it’s simply the result of water vapour in the air condensing on a cold surface. We have a Karcher window vacuum, which I use on the windows (and the bathroom tiles after showers), and it’s amazing to see how much water it takes in. I’d suggest getting one as it’s more efficient than wiping the water up with a cloth.

+1 to the Karcher window vac (cheaper window vacs are available), we use one daily on some old double glazing in the bedroom as it gets covered in condensation overnight, especially in this weather.

It's horrible having to keep dealing with mould, and i'm super grateful i'm not in that boat any more. 4 years in a damp rental. Beautiful house - fucking awful mould problem.

I used to have an empty spray bottle (like a flash cleaning bottle) with a top you could twist off and get back on, and put in about a third of cheap loo bleach (£1 Tesco) and top it up with water, quick shake (don't shake it till it's foamy, it won't spray well) and used that to spray all the visible mould. Let it sit and bleach the black away and then you can wipe it all down with a wet (water) cloth. Used to last about 3 weeks before it crept back.

I used to have to do all our window surrounds and the kitchen ceiling in all the corners through winter months. I'd clear the counters and put a shower cap and some cheap goggles on and do this, then run out and let it drip dry. Then go in after a while and wipe down the counters and the floor. If i hadn't done this the whole ceiling would have been covered in black mould by the end of winter 😔

It's a smelly and depressing job to have to keep doing and you need to make sure you don't breathe too much bleachiness in or get it on your belongings (or near your kids or your pets obvs)

I tried all the different £££ 'mould killer' sprays, and none were any better than the cheap bleach method.

Sorry for the ramble but it might be of help to anyone else going through this.

I agree with PPs the windows are probably just old/shit. We used to have condensation all over our windows in the winter mornings. I would use a karcher vac and the tank would be a couple of inches full each day! We had new windows put in in the summer and have had absolutely no condensation this winter. It's so nice not having to vac every morning now!!

I think your de-humidifier is broken, possibly it's a compressor type which needs to be warm?

At 48 humidity and 16c the dew point is 5c - i seriously doubt the inside of your double glazed windows are that cold.

Clean out the filters in the de-humidifier. Open trickle vents, if you have them. Dust collects mould spores. Vacuum and dust regularly. Get a thermometer that has both temperature and humidity indicators. Humidity should be below 50.

Watching this thread with interest.

"We keep the windows closed overnight as we're by a main road"

Main roads are a problem with dust particles entering the house. Night time may be better to open the windows because of less traffic.

The seals have failed in between the two double glazing panes so it is no longer functioning as double glazing.

That's why you are getting condensation on the inside one.

16 degrees! 🥶

We have something like this on our bedroom windowsill and it really works. You get refillable cubes which reduces the plastic waste

How long do you have the dehumidifier on for? No matter what the RH is showing as, mine has to be on all day to make a difference to the condensation. I still get a little mould in some rooms but like a pp, I just clean it off with bleach. I use it neat on a small paintbrush.

If you are getting condensation between the panes that doesn't clear then the glazing is blown and needs replacing.