Condensation on External Glass Windows

[Futsal]

I have a project that I'll be looking at in Aust. They have a block of home units that gets massive condensation on the inside of the glass windows and this leads to serious mould issues and corrossion/damage to the window surrounds.

Im thinking double glazing.

This problem is surely not unique. What do other countries do where it is very cold outside and warm inside (due to heating) to stop internal condensation on external glass faces?

 

[SAK9]

Two ways to skin this cat:
Cheap option :Have the heater/grill located close to the window to keep the glass temperature above condensing
Costlier and better optionouble glazing

 

[Futsal]

Thanks

 

[IRstuff]

Note that cheap double paned windows will also get condensation, so don't pick the lowest price.

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[willard3]

You can also try to control the moisture inside the building along with double or triple pane windows.

 

[IRstuff]

How massive is the condensation? Perhaps a dehumidifier is required. Is there something peculiar about these particular homes that result in high internal humidity? I've got a friend that has an indoor hot tub and sauna, so something similar could result in extraordinarily high humidity

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[chicopee]

Air conditioning should be able to control the humidity within the homes.

 

[Drazen]

i feel something is strange, condensation on cold windows is more of a problem in siberia than in australia.

am i missing something? what is your winter design temperature, and did you measure humidity in your rooms? can you tell us exactly which type of windows do you have, to give u-value estimate is even better?

 

[ChasBean1]

Futsal1st,

If you have condensation problems inside it means it's really cold out and you have high humidity in the indoor air. If you have condensation problems on the exterior glass it would be more understandable - a humid environment and a cooled interior (e.g., outdoor dew point is over 70°F, but indoor temp is 70°F or less, meaning window surface temperature is cool, producing condensation from outdoors).

 

[sprinkler1000]

South of the ecuator they are in Winter, and around the same latitude that I am.

It is very common to have cold temperatures outside (in the range of 2-10 ºC), and high humidity inside. If the window pane is simple glass it will condensate on the inside for sure, even in some cases with air conditioning.

Double pane glass is the solution.

regards

 

[DRWeig]

I agree with insulated (double or triple pane) glass.

Less expensive might be baseboard heaters beneath each window? That might help with drafty discomfort inside too.

Best to you,

Goober Dave

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[ozmosis]

I assume the poster does mean Australia and not Austria...

 

[Futsal]

Yes its in Australia but not near the coast. The outdoor design in winter is around -1.0C.

The condensation is on the inside of the external windows. Sounds like double glazing and adequate ventilation for wet areas is the answer. I'm a little surprised there are no little window heaters for really cold areas. Maybe the same things that go on car rear windows or similar.

Anyway thanks for the input guys.

 

[ozmosis]

Having moved down to the Southern Hemisphere from the northern, I'm constantly baffled by the lack of good insulation and adequate ventilation. Very few homes have double glazing, let alone triple. The amount of heat and cooling going via glass is quite obscene really.

 

[Drazen]

i am wandering how humid can it be on the inside, heating outdoor air which is really wet will lower humidity witin reasonable range.

it is likely issue of really, really badly insulated windows. it's good they are rusty now, it will be easier for you to decide on replacement.

 

[317069]

has this problem been only seen in this specific home units or it is a common in the area, I mean for sure there are many other home units in the area have the same single windows, did they suffer the same problem.
can you check the humidity ratio(%RH) inside this spaces, what type of HVAC system is used, is it air system or what, Are these units ventilated properly,
(-1C) outside design will not cause whole this problem otherwise we would see it everywhere, if double glass would solve problem in an area with -1C design temperature, what about areas with -20C or less like Canada for example, in this case we may need triple glass or more which is not the case.

 

[EnergyProfessional]

Get some really good windows. not only you avoid condensation, you also reduce energy usage and more importantly provide comfort. A cold glass pane makes people feel cold as they radiate heat towards it.

I don't know your market, here in the US there are "alpen fiberglass windows" with 7L glazing that have overall U-values down to 0.14 (imperial, not metric!). I use them in many buildings (Fire Stations, other commercial applications) and in every meeting with the Fire Chiefs they tell me how much they like the windows just for how warm the room feels after replacing older double-pane windows and they budget for replacing windows in all the fire stations because the crews like the comfort. So imagine how much improvement after replacing single-pane windows.

Looking at overall U-value (and if you calculate correctly you realize a single bad envelope element kills overall performance quickly), windows and doors are the weakest link in a building. Want to amke a chain stronger? Reinforce the weakest link.

In addition obviously check indoor humidity. But the single-pane I think is the cuplrit.