Condensation on bedroom windows in the morning.

pipo123

New Member
Messages
2
Hi folks,

I’m wondering how to solve condensation on my bedroom windows in the morning. My OH keeps some photo frames on the window sill and have just realized this morning that one of them has gotten mouldy.

Windows are PVC double glazed. Curtains are closed at night, probably trapping cold air there. Room does not have a vent to the outside, but it does have trickle vents on the windows. North facing. Door closed at night. Rented property so can't do any mad DIY stuff. House is pretty well insulated, never gets too cold.

I have read many threads around and just need a couple of pointers.

1: Install trickle vents.

We already have them on all windows in the house, and they’re open.

2. Use a dehumidifier.

A big dehumidifier came with the house (bad sign?) How do we get to sleep when it’s on? Or do we run it during the day? For how long? How often?

3. Open the window when you sleep.

We live on the ground floor in an urban area so can’t fully open it, but will open it on the “latch” open function and see if it works.

4. Put that melted plastic cling film stuff from amazon on it.

Does this work?

5. Ventilate the house.

There is a positive input ventilation contraption in the kitchen only. In the farthest corner of the house. Shouldn’t it be in the hallway so it can get to all rooms in the house? It’s pretty useless then, am I right? I’ve also read that the house must be airtight for this to work. We have trickle vents on all windows. I was thinking of turning this OFF as it just constantly blasts cold air into the kitchen. It’s like a butchers walk in freezer in the mornings.

6. Use an extractor fan when cooking.

We do.

7. Use an extractor fan when showering

The shower does not have one, nor does it have a radiator. We crack the window while showering.

8. Do not dry clothes on radiators / hangers etc.


We don’t We use a condensing tumble dryer.

9. Heat the room that has the condensation problem

It is heated for 8 hours a day. Not heated at night as the house is fairly well insulated and well, we're asleep.

What can I try next? Or am I doing anything wrong? Note - there is some slight condensation on living room window in the morning too. Also north facing. In fact the whole pace is north facing.
 

NoRegretsCoyote

Frequent Poster
Messages
2,024
Short term, try running the dehumidifier in the room in the evening and switch it off just before bed. This should lower the humidity before it gets raised again by two people breathing in the room for seven hours.

Alternatively you can try leaving the dehumidifier on while you sleep and use foam earplugs. I'm a heavy sleeper so can manage this but it's not for everyone.

A dehumidifier is expensive to run and IMO the landlord should help you with the cost as you are protecting his/her property.

Long term, you may need to get the landlord to install an external vent. There is a trade off here in terms of more noise if you live in an urban area.
 

Micks'r

Registered User
Messages
59
1: Install trickle vents.
We already have them on all windows in the house, and they’re open.
2. Use a dehumidifier.
A big dehumidifier came with the house (bad sign?) How do we get to sleep when it’s on? Or do we run it during the day? For how long? How often?
3. Open the window when you sleep.
We live on the ground floor in an urban area so can’t fully open it, but will open it on the “latch” open function and see if it works.
4. Put that melted plastic cling film stuff from amazon on it.
Does this work?
5. Ventilate the house.
There is a positive input ventilation contraption in the kitchen only. In the farthest corner of the house. Shouldn’t it be in the hallway so it can get to all rooms in the house? It’s pretty useless then, am I right? I’ve also read that the house must be airtight for this to work. We have trickle vents on all windows. I was thinking of turning this OFF as it just constantly blasts cold air into the kitchen. It’s like a butchers walk in freezer in the mornings.
6. Use an extractor fan when cooking.
We do.
7. Use an extractor fan when showering
The shower does not have one, nor does it have a radiator. We crack the window while showering.
8. Do not dry clothes on radiators / hangers etc.
We don’t We use a condensing tumble dryer.
9. Heat the room that has the condensation problem
It is heated for 8 hours a day. Not heated at night as the house is fairly well insulated and well, we're asleep.

What can I try next? Or am I doing anything wrong? Note - there is some slight condensation on living room window in the morning too. Also north facing. In fact the whole pace is north facing.
1. good
2. yes, bad sign. Dehumidifiers are artificial ways of getting rid of moisture. Shows there's an imbalance somewhere in the heating/ventilation/moisture load triumvirate. Only use as a last resort.
3. Even opening it a crack will help. Do you sleep with you bedroom door closed? Perhaps open it too to aid air movement.
4. No
5. I don't like them but having said that they are generally installed in the landing ceiling, not in the kitchen.
6. good
7. Try to open other windows / doors to create a cross flow of air to aid the exhaustion of the moisture laden air.
8. These create a lot of air borne moisture. Try to ventilate the room where it is when using it. Again open internal doors / windows
9. Good

You appear to be doing most things correctly.
Your issue appears to be a combination of excessive moisture buildup caused by inadequate ventilation combined with some immoveable objects such as north facing. Imo, the area to concentrate on to tackle this is to address the ventilation issue with a well designed central extract mechanical system which is unfortunately outside your control as the place is rented. Perhaps your landlord is interested in solving this issue once and for all.
 

PebbleBeach2020

Registered User
Messages
109
What damage is a little condensation on the windows going to cause? Just dry it off and open windows for few minutes when u get up no?
 

elcato

Moderator
Messages
3,559
A good de-humidifier which can be put on low (thus reducing noise) is your best bet. Use a timer socket to get it to switch on at say 5 am. Switch it on for an hour when going to bed. The only other solution (within your range) is to heat the room overnight as well.
 

Leo

Moderator
Messages
12,030
Where is it answered already please?
The OP said they are already getting mould growth. Mould spores cause respiratory problems and over time result in structural problems.

The presence of significant amounts of condensation is a warning sign that there is a problem. A quick wipe just masks the issue, it's usually best try to fix it.
 

pipo123

New Member
Messages
2
Thanks folks, I will give the dehumidifier a go for a few days. Never used one before so might be some trial and error.

I'll also try crack a window in the bedroom, and crack a window at each end of the house to get a bit of air flow going.

I came across another forum where somebody used one of these for the windowsill, a little heater for plants like this: edit: it looks like I can't use amazon links. Anyway it's a white, tubular 55w heater. Just google it and you'll get the idea. They're about €20 on amazon.

They just stuck it on the windowsill at night and it sorted the condensation. Doesn't emit a huge amount of heat, 55w. But was apparently enough to heat the small area between the curtain and the window. What do you think? Good idea?
 

Leo

Moderator
Messages
12,030
They just stuck it on the windowsill at night and it sorted the condensation. Doesn't emit a huge amount of heat, 55w. But was apparently enough to heat the small area between the curtain and the window. What do you think? Good idea?
A heater will just raise the temperature of the window to stop condensation forming, but remember it won't address the root of the issue. The moisture will still be present in the air and you may have condensation forming in other less visible areas.
 

SPC100

Frequent Poster
Messages
679
Cold windows and wet air results in condensation. Warm up the windows and/or lower the moisture in the air/house.

Buy a digital hygrometer or two and use it to measure air moisture level especially in bathroom but maybe bedroom too.

Leave bathroom window open with bathroom door closed after shower till it falls back to normal levels. Normal will depend a bit on the days weather.

Open bedroom windows more during the day to change air and help remove moisture from contents of bedroom.
 

Marsha25

Frequent Poster
Messages
133
Since moving into our house 20 years ago, we have put in extra insulation to crawl spaces; got new windows upstairs, sealed around the windows more recently with silicon, which helped a bit; keep Aero360 moisture absorber in each bedroom; keep vents open, but condensation is still an issue in 2 rooms. Two sons share a room and there is always more condensation on their window than there is on ours. Our daughter has her own room and there's rarely any condensation on her window. There's not much more we can do apart from breathing less :) I dry off the condensation when I get up and open the windows for a while. That keeps the mould at bay.
 

Gervan

Frequent Poster
Messages
1,071
There are chemical dehumidifiers you could try, (less noisy than electric) or put a bowl of salt on the windowsill to absorb the moisture.
 

elcato

Moderator
Messages
3,559
Since moving into our house 20 years ago
Yep and while we are at it, I have had this problem all my life no matter where I slept (apart from the 5 star grass when inter-railing years ago). The only solution is to bring the heat in the bedroom up to your normal heat which can be uncomfortable for a lot of people and not very cost effective for others.
 

Coldwarrior

Frequent Poster
Messages
266
Yep and while we are at it, I have had this problem all my life no matter where I slept (apart from the 5 star grass when inter-railing years ago). The only solution is to bring the heat in the bedroom up to your normal heat which can be uncomfortable for a lot of people and not very cost effective for others.
Extra ventilation should solve or at least reduce the problem, but who wants a drafty dumb vent in their bedroom wall. A heat recovering mechanical ventilation system would likely be the best solution but these would be 4-5k for just upstairs I believe.
 

shweeney

Frequent Poster
Messages
309
Extra ventilation should solve or at least reduce the problem, but who wants a drafty dumb vent in their bedroom wall. A heat recovering mechanical ventilation system would likely be the best solution but these would be 4-5k for just upstairs I believe.
single room MHRV are available that replace the existing wall vents, there are various makes but about €300 per room, plus whatever it costs to get power to the location.
 
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