Condensation in Rationel Auraplus windows

[dnoble]

We are currently in our second winter in the house. MBC passive house with MVHR

Two of the triple glazed casement windows appear to have significant condensation problems. 

One is in a bathroom (with good air extraction) and the other in a home office. 

I've just written to Rationel aftersales support but after previous problem with a faulty door locking mechanism, I'm expecting an initial brushoff.

Do folks feel this suggests a particular failing in the window?

Edited February 9, 2021 by dnoble
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[the_r_sole]

It looks like the condensation is on the inside face of the window? that's a ventilation issue rather than a window failure, you're creating a huge amount of stream in a bathroom and if it's not getting drawn out it will condense somewhere

[ProDave]

Nothing but a tiny amount of condensation on the very edges of the glass on my Rationel windows.  And I am sure it's a good deal colder here.

 

I suggest a ventilation problem.  Has you MVHR been ballanced?  Are you using boost while showering?

[Thedreamer]

What's all the other stuff?

 

If we have any condensation I usually just give a quick wipe down each day.

 

Ventilation needs to be checked.

 

 

 

 

 

 

[jack]

We get a breath of condensation on the bottom of our 3G windows in the bathroom when it's very cold outside and the shower's been on for a while. Even without boosting the MVHR, they clear within half an hour. 

 

I can't imagine condensation on the inside of our 3G windows so bad it forms droplets like that, so gut feel is that there's something wrong with the window itself. Is there any evidence of air leakage within the glazing units?

[Mr Punter]

That looks like high humidity.  Have you got a hygrometer / humidity sensor?  Try it in the office.  Open the supply valve in there.

 

In the bathroom is the extract vent directly above the shower?  Does this only occur within an hour of bathing / showering?

[craig]

95% leaning towards a ventilation issue rather than a unit failure. 

[Conor]

You also have a mouse problem.

[Onoff]

Get zero condensation on the inside of my 2G bathroom window. That's because inside and outside temperatures are near equal I guess!

[Olf]

11 hours ago, Onoff said:

That's because inside and outside temperatures are near equal I guess!

No, this would actually make it worse, because...

21 hours ago, dnoble said:

Two of the triple glazed casement windows appear to have significant condensation problems.

... condensation forms when the air temperature drops below dew point. The higher the moisture content (relative humidity), the higher the dew point, the earlier (at higher surface temperature) condensation will occur. And the warmer the air, the more moisture it can hold.

So what you have is high humidity in the bathroom (too much steam generation or poor extraction) or poor window insulation (that includes how it is mounted - my 'FENSA' installers only used mastic to hide the gaps (poorly as well) to close the gaps, there was a cavity at external temperature with cold draught from between the window frame and windowsill) - or both

 

Invest in £10 hygrometer to get some idea of local relative humidity and temperature to start with