Window condensation and mould help!

Apodemus

Bendy_House said:

FreeBear said:

Bendy_House said: 3) During the day, open the windows (as many openers as it has) a good half-wide or so (as long as rain doesn't come in), 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).

But if it is wet/misty/foggy outside, all you are doing is letting damp air in to the room.

Outdoor humidity over the last week has been 75-85% whilst indoors, around 60%. I'd rather keep that cold damp air out, so windows are firmly shut.

But so is my garage - bone dry in all weather, and no heating in there other than what it gets from the sun. The air inside the garage might feel a bit damp when the outside air is absolutely saturated, but nothing condenses on surfaces inside the garage, and there's now't forming on the insides of the windows. It is dry. 'Cos it's draughty.

Yes, but there is dry and there is dry!  My concrete garage is dry - wood shavings and sawdust stay dry, they don't become a doughy mess, leaves stay crinkly-dry - but if you leave bare metal, it rusts much faster than it does inside the house.  The concrete garage feels cold in all weathers, but when I had a wooden garage, it always seemed warmer and rust was less of an issue.

newlywed

shiraz99 said:

mrsmsebastian said:

Ben1989 said:

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.

What is PIV

https://www.nuaire.co.uk/residential/positive-input-ventilation

Our landlord fitted one of those in our flat… freezing cold air blasts into our hallway all through winter and there is no off switch.  The ducting went along the top of a bedroom above bunk beds and would drip with condensation each night, onto a child’s head. 

The vent is sited right outside the block where everyone stands and smokes… so it’s not just cold air it pulls in.

There is no off switch either (we pulled the fuse)

think carefully about vent and duct placement and go for an inbuilt heater.

youth_leader

Plan didn't work, it was a cold night and only 3C here this morning. All windows at the front, east facing, are covered in condensation this morning.  Dried it all and dehumidifier on, showing 70.  

Effician

youth_leader said:

Plan didn't work, it was a cold night and only 3C here this morning. All windows at the front, east facing, are covered in condensation this morning.  Dried it all and dehumidifier on, showing 70.  

You may want to check the direction of air flow through the trickle vents ( even when closed) , if it's cold air coming in then the panes of glass underneath will soon get below the dew point of the air in the room, ie lets say the room is 18c with a 55% RH & the internal window pane has 3c air dropping down it , it won't take long before the dew point of 8.8c is reached & condensation forms.

SunnySteph

I'm having a similar problem at the moment - mould and condensation in all the windows. 
I've bought a dehumidifier, but already running a heated airer to dry clothes and worried about pushing my electricity bills up further. Wondering if it's cheaper to just have the heating on more, but it's a very confusing minefield!

My house is 1960's solid concrete walls (no cavity insulation) and every room has a vent for ventilation but clearly it's not working (draughty sure, but not stopping the build up of moisture). No fan in the bathroom thought I usually open the window to vent it after a shower etc). 

Anyone know how much a PIV system would cost to install? Would that help to reduce the moisture issue? Windows are already double glazed though I suspect some have draughts and are not well installed.