Window condensation and mould help!

mrsmsebastian

We recently got the glass unit replaced due to condensation inside the glass and fitted a window vent hoping to resolve the mould forming on the sill. Unfortunately still exist as shown in the pic.
Can you please tell me what else can I do to prevent this from happening. Shall I replace the whole window?
Thanks

shiraz99

Get a dehumidifier. The room clearly has a very high relative humidity.

grumbler

OR increase the temperature (relative humidity will drop) and/or deal with the sources of humidity (cooking, showers, drying your washing).

OR install much more expensive windows with better insulated frames and triple glazed units.

mrsmsebastian

grumbler said:

OR increase the temperature (relative humidity will drop) and/or deal with the sources of humidity (cooking, showers, drying your washing).

OR install much more expensive windows with better insulated frames and triple glazed units.

With cooking I always turn the cooker vent on and shut the kitchen door. Never hang clothes inside the house and bathroom has adequate ventilation. 
With the condensation present on the glass and mould on the sill, does it mean the room is too cold or hot? Shall I increase the room temp or just leave the window ajar to allow air in?

shiraz99

Warmer air doesn't get rid of moisture it just holds onto it better but as soon as the air comes into contact with a cold surface, eg, your window, it will condense and if you don't get rid of the water you'll get mould. Increasing the heat in the room, on it's own won't achieve what you want 

grumbler

mrsmsebastian said:

grumbler said:

OR increase the temperature (relative humidity will drop) and/or deal with the sources of humidity (cooking, showers, drying your washing).

OR install much more expensive windows with better insulated frames and triple glazed units.

With cooking I always turn the cooker vent on and shut the kitchen door.

Is it definitely extracting, not recirculating?

With the condensation present on the glass and mould on the sill, does it mean the room is too cold or hot? Shall I increase the room temp or just leave the window ajar to allow air in?

Difficult to say. My windows are of very poor quality, I never heat my bedroom and hardly ever open the windows in cold seasons, except in the bathroom. Sometimes I do get condensation in the bedroom in the morning, but not to that degree that I see in your photo.

FreeBear

Try some thick thermal curtains that are a close fit over the window. If you have a radiator below, tuck the curtains in behind it in an evening.

Ben1989

There's the same amount of moisture in the air so heating up won't help as as soon as it hits it it'll cool and condense (hence why it's called relative humidity).

May I suggest a PIV. Since installing I get zero condensation on all my windows, not a single drop.

Chloe_G

Can you install a PIV in a house without a loft? ie. with a completely flat roof - 1930s art deco style.

Bendy_House

MrsB, I'm going to go all 'S62' and say that this room is north-facing, and is a bedroom?

That is pretty extreme condensation, and is probably what you wake up to each cool morn? 

You asked if it's a case of that room being too hot or too cold. It's neither. Yes, you COULD heat up that room by a large amount - let's make it, ooh, 23oC - and that cond WOULD 'go away' (it would evaporate again), but it would still be inside the room and house in general, and you'll find it condensing out in the next coolest room.

So, that isn't a solution. The answer is largely down to ventilation. If that is the worst room, then you'll see results in a day.

First, as Grumb asks, does your cooking extractor 'actually' extract to the outside? It's worth going over your house and ensuring all excess moisture is removed at source; bathroom running for at least 5-10 minutes until the room is FULLY dry. After cooking, bathing, and washing, the next biggest source of moisture is likely to be human bodies. Now't you can do about that.

Next, this is what to do with this bedroom:
Mop up the cond. Use an absorbent cloth, wrong it out, and keep going. Finish with a paper towel. Spray a light layer of mould killer on any affected surfaces, leave for a goodly while, and wipe off (the stuff can bleach - take care).

Ok, the biggies. Turn off (or down to 'frost') the rad in that room. Open the window (as many openers as it has) nicely wide, and shut the door. Leave it. When you go back in, it'll be cold - but DRY. (Remember - keep the door shut at all times).
In the evening, close them to 'vent' setting. A half or one hour before bed, turn up the rad (unless you are brave enough to just dive under the covers in a cold room...) 
Turn off the rad before bed, but leave the windows on vent overnight. Bedroom door shut at all times.
A half hour before you wake up, you can have the heating come on. Jump out of bed and, if it's breezy, you can Temporarily shut the windows whilst you get ready, but crack them to vent again as soon as you are out of the room, and rad down to frost again. 

And cond along the bottom of the window - I'm guessing there will be 'some', but it should be a LOT less - wipe away as before.

Please report back.

Coffeekup

mrsmsebastian said:

grumbler said:

OR increase the temperature (relative humidity will drop) and/or deal with the sources of humidity (cooking, showers, drying your washing).

OR install much more expensive windows with better insulated frames and triple glazed units.

With cooking I always turn the cooker vent on and shut the kitchen door. Never hang clothes inside the house and bathroom has adequate ventilation. 
With the condensation present on the glass and mould on the sill, does it mean the room is too cold or hot? Shall I increase the room temp or just leave the window ajar to allow air in?

Is that the kitchen? It looks like it's facing north so it's the coldest room/part of the house. If so I would open the window whilst cooking and leave open till 10 minutes after cooking on the hob. If you have a gas hob I'd open the window as soon as you have the gas on as gas once burning expels moisture. If you have another window or door in that room whilst cooking, if you see it starting to condense heavy open the above to have 2 points of airflow, much of the moisture will shoot out.

I used to have a similar issue till I realised the hood did very little, now I always have the window open whilst using the hob. I also have 3 old jam jars half filled with salt from October till march on the window sill to soak up any new moisture forming, I no longer have issues with images like you currently have.

You could also get in the habit of squeegeeing the window if you see it starting to get heavy. You could also leave the window open/ajar during the day to get rid of the excess moisture, (if you do this turn you heating thermostat to off or very low to stop the boiler kicking in all the time whilst you're out.)

In my experience of living in cold and draughty house's, I doubt a new window will make any difference.