Condensation and PVC Window Use

The incident which is called “humidity” colloquially is actually the water in the form of vapor in the air. There is always some water vapor in the air of the environment we are in. The ratio of the water vapor amount contained in the air to the amount of maximum water to be carried by the air at the same temperature is called relative humidity. Maximum amount of water to be stored by the air in 1 cubic meter area is 17,5 gr. If there is 10gr water vapor in the air of such an environment, the humidity ratio is determined as 57%. [(10/17,5)x100=57]

Water vapor in the air has a certain condensation temperature. When the air is in contact with surfaces colder than the environment, if the surface temperature is lower than the condensation temperature, the state of water vapor in the air changes to liquid. This is called condensation. Minimum values for no condensation to occur on the surface temperatures depending on the humidity rate and environment temperature are given in the table below.

Humidity Ratio
30% 35% 40% 45% 50% 55% 60% 65%
30 10,5 12,9 14,9 16,8 18,4 20 21,4 22,7
29 9,7 12 14 15,9 17,5 19 20,4 21,7
28 8,8 11,1 13,1 15 16,6 18,1 19,5 20,8
27 8 10,2 12,2 14,1 15,7 17,2 18,6 19,9
26 7,1 9,4 11,4 13,2 14,8 16,3 17,6 18,9
25 6,2 8,5 10,5 12,2 13,9 15,3 16,7 18
24 5,4 7,6 9,6 11,3 12,9 14,4 15,8 17
23 4,5 6,7 8,7 10,4 12 13,5 14,8 16,1
22 3,6 5,9 7,8 9,5 11,1 12,5 13,9 15,1
21 2,8 5 6,9 8,6 10,2 11,6 12,9 14,2
20 1,9 4,1 6 7,7 9,3 10,7 12 13,2
19 1 3,2 5,1 6,8 8,3 9,8 11,1 12,3
18 0,2 2,3 4,2 5,9 7,4 8,8 10,1 11,3

On the assumption that room temperature is 23 °C and humidity ratio is 45% in the table above, for the condensation to occur at any surface, temperature of that surface should be equal to or lower than 10,4 °C. Due to this reason, for the condensation to be prevented, increasing the indoor temperature levels is one of the most effective methods. This can be achieved by insulating the walls from the outside and using glasses with low heat transfer coefficient.

Condensation may be prevented with the methods below;

  • Increasing the indoor surface temperature of the building with insulation. (20–22 °C)
  • In order to decrease the humidity ratio of indoors, it should be aired for at least 3 times each for 15 minutes by opening the sash with the help of turn and tilt system.
  • Preventing the humidity from reaching other rooms by closing the doors of internal humidity sources (such as laundry drier, bathroom and kitchen).
  • Not using the heaters such as Gas stove, catalytic which produce water vapors.


  • For a longer service life, it is important to grease the espagnolettes, which are the mechanisms constantly working since they are made of metal and they constantly move, in every 6 months.
  • Profiles should be cleaned with warm water, powder detergent should not be used so that surface wear should not occur, and cleaning should not be carried out via surface wearing materials such as sponge, sandpaper.
  • Materials such as thinner which could harm the surface and cause the material to lose its composure should not be used in the window surface cleaning.
  • Protective folios applied on the profile surfaces are used for the purpose of protecting the profiles from the impacts which might occur during transportation or assembly. Protective folios should be removed after the assembly. If the folios are not removed for a long time, it would be harder to remove the folios which have been exposed to the sun for a long time. Protective folios should be removed in maximum 3 months after the assembly.
  • Materials such as paint, mortar which could be formed on the profile in construction environment should be immediately cleaned and hard objects and chemicals like thinner should not be used for cleaning them.
  • The labels on the glasses which are assembled into the windows after the first assembly should not be removed with hard objects, they should be removed with the help of a cloth dampened by warm water and after the label is softened via hot water.