Why do windows fog up on the outside?
Windows tend to fog up on the outside mainly during the transitional seasons – spring and autumn – although it can also happen at other times of the year. This problem largely affects buildings situated near water, in the vicinity of marshes or forests, where the most moisture is present. Windows on north-facing facades, which receive the least sunlight during the day, are most sprone to fogging.
Temperature difference. How does condensation form on the glass?
The main cause of condensation on the outside of windows is a significant temperature difference between the interior of the building and its surroundings. Water vapour condenses on the rapidly cooling surface of the glass when moist air rising from the ground, bodies of water or plants comes into contact with it. This usually happens when the flat is no longer heated at night, and the outside temperature rises and falls sharply in a daily cycle. This causes moisture to settle on the windows and other surfaces, which then turns into characteristic droplets, most often in the morning or at night.
When should we be concerned about windows fogging up?
Although windows fogging up is a natural phenomenon, there are situations where it may indicate problems with thermal insulation. If water vapour condensation occurs inside the glazing unit, i.e. between the panes of glass, this suggests a leak or structural defects. In such cases, it is worth consulting a professional to prevent further problems with damp, heat loss and mould growth.
Paweł Buchman, DAKO Product Manager at the Drewno Group, explains:
– Condensation inside the glazing unit is a sign that should not be ignored. It indicates a leak in the spacer bar and the loss of the inert gas responsible for the window’s thermal insulation properties. Such a pane ceases to fulfil its function: it no longer protects against heat loss and simply becomes unsightly. In this situation, the only effective solution is to replace the glazing unit with a new one, which, with modern systems, can be done without having to replace the entire window frame.
What can be done to prevent windows from fogging up on the outside?
It should be noted straight away that there are no universal ways to eliminate the problem of external condensation on standard window panes. Even with room ventilation, the use of micro-ventilation and the adjustment of air vents, we have no control over the weather conditions responsible for condensation on this side.
The good news is that you can completely eliminate this problem or significantly reduce it by using anti-condensation glass, which is also available as an option in DAKO windows. This type of glazing significantly delays the onset of condensation and often completely eliminates the presence of water vapour on the outer pane of glass. This ensures full visibility even in changeable weather, throughout the different seasons.
It should be noted straight away that there are no universal ways to eliminate the problem of external condensation on standard window panes. Even with room ventilation, the use of micro-ventilation and the positioning of air vents, we have no control over the weather conditions responsible for condensation on this side.
The good news is that you can completely eliminate this problem or significantly reduce it by using anti-condensation glass, which is also available as an option in DAKO windows.
– This is a technologically advanced solution featuring a special, hard coating on the outer surface. Its purpose is to raise the temperature of the outer pane of glass and alter its properties. As a result, water vapour does not settle as tiny droplets that impair visibility, but evaporates more quickly or runs off. This type of glazing significantly delays the onset of, and often completely eliminates, water vapour on the outer pane of glass. It is an investment in a clear view and visual comfort, particularly useful in energy-efficient homes with a very low Uw coefficient, where the phenomenon of external condensation is most noticeable – emphasises the expert.
Summary – Why do windows fog up on the outside?
In summary, windows fogging up on the outside is the result of natural processes related to temperature differences and does not indicate problems with thermal insulation. By investing in windows from DAKO, we can be sure of high-quality workmanship, excellent thermal performance and adequate micro-ventilation, and temporary water droplets do not indicate a product defect. Furthermore, by fitting them with anti-condensation glass panes, we can eliminate this problem altogether.
