External condensation on double glazed windows

Birka

I've noticed a large area of condensation on the outside surface of the double glazed units on two bedroom windows on colder mornings (its a bungalow so they're at the same height as unaffected windows). The condensation is limited to the middle of the glass and doesn't affect the edges. It seems to me that there's heat transmission between the interior facing glass surface and the exterior surface yet there's no condensation in the double glazed cavity so that seems to be intact.

They're Munster Joinery argon filled units, approx ten years old.

Any idea what's causing it?

10-10-20

Same as this thread.

https://www.boards.ie/discussion/2058211941/condensation-outside-tiriple-glazed

The losses around the periphery of the glass is slightly larger, keeping it slightly above the DP.

LimerickGray

https://www.boards.ie/discussion/comment/118101246#Comment_118101246

oddly I was in Poland last week. Various DP and various temperatures from 4C to 15C early AM. didn't see such. condensation on exterior or triple anywhere. I think it is a coating on the glass

10-10-20

You'll only see it in cooler rooms. Heat the interior window pane somewhat and the condensation stops.

In shops and warmer rooms/locations, or where there is breakdown in the insulation/U-value, it doesn't happen.

Wildly Boaring

It's a good sign.

Means your external window is cold and not losing heat.

Only happens with certain dew point outside.

https://www.energlaze.ie/external-condensation-windows/

Dudda

https://www.boards.ie/discussion/comment/118104468#Comment_118104468

We probably have a milder climate with more moisture in the air coming in from the Atlantic. It also depends on the weather and doesn't happen all the time, just on cold damp but not raining and no or light wind nights.

LimerickGray

https://www.boards.ie/discussion/comment/118105615#Comment_118105615

I get this every morning on all windows. its been like this for few months. not weather dependent, although it is worse if it is colder/damper outside. inside is warm. I've tried leaving off the heating in rooms to see if it matters 0 it does not

Dudda

https://www.boards.ie/discussion/comment/118106393#Comment_118106393

Are you on about condensation inside or outside like the original poster? And is it triple or double glazed you have? Having it every morning for the last few months is very unusual as that would bring you back to summer when it isn't as common.

LimerickGray

https://www.boards.ie/discussion/comment/118107919#Comment_118107919

IMG_0149.jpeg

ij

LimerickGray

CORRECT Orientation

LimerickGray

does the ERC logo look backwards?

this image is from the inside and other panes are the same

10-10-20

https://www.boards.ie/discussion/comment/118105615#Comment_118105615

Apparent it's more common when there is grass or leafy matter under the window as there will be more moisture coming up off the plants.