Condensation on double glazed windows

[macacao]

I have just bought a 100 year old rubble fill stone house. The double glazed windows in my bedroom are a few years old and it gets really bad condensation- does this mean that the glass unit is knackered and needs replacing or does it just need a trickle vent retrofitted?

 

[Richard C]

Faulty double glazed units could be a factor but condensation doesn’t necessarily mean your windows are knackered; condensation is caused by high humidity levels inside the room which condenses on the colder window surface. Many things cause high humidity; damp could be penetrating through those solid walls, a leaking gutter, drying washing inside the property, the type of heating system or insufficient background heating. Double glazing is excellent at sealing rooms & the biggest cause of condensation can be lack of adequate ventilation. One person can exhale around a litre of water in 8 hours & if you sleep with the bedroom window closed & the door shut, there is nowhere for moisture to escape; drawing the curtains can help. Extract fans in bathrooms, utility & kitchen will also help by removing excess moisture & trickle vents provide overall background ventilation; all of these are now required under Building Regs on new builds.

 

[JohnD]

it is not clear if you mean condensation on the room side of the window, or inside the unit.

if you have an old rubble house it doubtless needs a lot of ventilation to keep it reasonably dry

//www.diynot.com/wiki/building:condensation_in_houses

 

[Richard C]

it is not clear if you mean condensation on the room side of the window, or inside the unit.

Maybe I wasn’t clear but on the inside of the window of course; if it’s inside the glazed unit then it’s clearly fu cked!

if you have an old rubble house it doubtless needs a lot of ventilation to keep it reasonably dry
//www.diynot.com/wiki/building:condensation_in_houses

Well of course it does; but many don’t understand the vast difference between a new property & a “chocolate box” purchase; I was taking a measured approach. Often problems only arise by folks trying to modernise old properties & it has to be done sympathetically to avoid affect the natural balance of old building techniques & providing additional ventilation is what I hinted at.

Shame you didn’t pick this up yesterday, would have save me the trouble.

 

[OnwardandUpward]

I have just bought a 100 year old rubble fill stone house. The double glazed windows in my bedroom are a few years old and it gets really bad condensation- does this mean that the glass unit is knackered and needs replacing or does it just need a trickle vent retrofitted?

I cannot see what difference it makes what house the double glazing is installed in. If it is condensation on the room surface then it is a wet house. If the condensation is in between the two bits of glass then the double glazing has blown. This is very common and happens just as much in modern houses as old ones.

It seems to be the way that the glass double glazing unit needs to be replaced.

The air (or gas) between the two sheets of glass warms up and cools down a lot - each time expanding and then contracting. In the end it finds a way out around the seal of the unit. Then each time it expands it blows out a bit of air and each time it contracts it sucks in some nice cold and moisture filled air. So the window slowly fills with moisture which sticks to the colder glass layer.

 

[JohnD]

we haven't had any clarification from macacao

It's been a week, perhaps he isn't going to tell us. Not much point in us guessing.