Double glazing condensation.

[denpunk]

Are certain makes of double glazing more prone to condensation than others? My upvc windows are running with condensation all winter, in heated and unheated rooms. I have patio doors, also upvc, which were fitted at a different time and are a different make yet they get no condensation whatsoever even though the window at the other end of the room is creating a pool of water on the sill....

[TWR]

Is the room ventilated?

[denpunk]

If I leave all the doors and windows open I obviously get rid of the problem. Even when un-ventilated there is no condensation on the patio doors which are only 1 metre from the closest soaked window.

[TWR]

You should have a vent in the roof / celling, is the vents clear of leaves etc? do you use a heater around the area of condensation? I presume the condensation is on the outside of the glass not inside!

[Gizmonster]

Condensation is formed by warm, moist air coming into contact with a cold surface (a bit more to it than that, but that's it in a nutshell).
If you're getting condensation on your windows, you either have damp air (do you dry a lot of clothes, boil pans of water, boil kettles or anything else that releases lots of water vaporr into the air??), or your windows are not very good at keeping the cold air out.
Best way to prevent this is to keep rooms well ventilated and try a de-humidifier, and/or get some new panes of glass with better thermal properties.
If you want a good read, have a look at: http://www.doityourself.com/forum/house-home-doors-windows/362701-condensation-inside-windows.html
..... and read Oberon's post about 8 posts down .....

[The Builder]

As you know, water vapour condenses on cold surfaces. Patio doors usually have 28mm DG units of superior (thermally) K-Glass. I guess your window isn't glazed as efficiently.

[Tilly2]

Are your windows still under guarantee?

[denpunk]

Unfortunately the windows were fitted before I moved into the property. Maybe they're inferior quality windows. They don't seem cheap rubbish ( I'm a builder and reckon I can spot poor quality). The window vents make little to no difference.

[TWR]

Again, Is the Condesation on the outside of the window?

[jomifl]

Get a humidity meter (about £5) then you will know if you are expecting too much from your windows. As a guideline for you at the moment it is 8C outside, 20C and 60% inside and no condensation on a single glazed window in our bedroom. I suspect you have a humidity problem rather than a condensation problem.

[gingejbee]

Most replies (except The Builder) have missed the main point in the question!

[starone]

I was quite interested in this question and answers den, because I recently moved out of rented accommodation. There was a small porch on the back, an addition to the house and I used it to dry my clothes when it was raining. There's only me so it wasn't much and I tried to dry most outside. I must admit it didn't dry very well, seemed to take forever. When I left the landlord said I had made the porch damp by putting my clothes there to dry. Would that be possible, anyone, especially gizmonster. I accepted what he said as I thought he must be right, and I can't do anything about it, but just wondered if he was right.

[Gizmonster]

@Starbuckone - if you dried your clothes in the porch and it was unventilated, it is possible you may have caused some degree of damp in the porch. The moisture that evaporated from the clothes had to go somewhere.
If you'd left the windows open, or a vent of some kind, then eventually most of the moisture would have probably left the porch.
However, if you left the doors and windows shut, the moisture may have migrated to within the structure of the porch.

[buildersmate]

Most replies (including the OP) continue to miss the point The Builder made.

The patio door has thicker DG units, ergo the temperature in the inside pane will be higher than those of the windows. Hence more water vapour will condense on the windows, even in the same room as the patio doors.

It is nothing to do with quality per se, except that older DG units were specified as thinner, in the good old days when energy was cheap and we didn't worry about the cost of fuel.

[denpunk]

Thanks @buildersmate & @gingejbee for getting the point spot on. Thanks to all who answered. A great site.
The funny thing is, my last place was over 100yrs old with ancient single glazed sash windows...........not a drop of condensation! With electric heating....never broke down in 20yrs there. I've been in this house less than a year (built 1971) terrible condensation and 4 boiler repairs...don't get me started!!!