Constructing a new window that eliminates condensation and improves insulation
The article “Warm windows without condensate” by Konrad Huber of ift Rosenheim documents what effect the airtightness of the building envelopoe has on the internal climate, and what this means for the windows.
Previously, air leakage through the building envelope provided air changes which are no longer present. Relative humidity has therefore increased.
Brief periods of ventilation several times a day have only temporary effect as moisture is contained in walls, ceilings and furniture. The moisture discharged by ventilation is quickly replenished, and depending on the external temperature, condensate will form near the glass edge.
Tougher directives aimed at encouragng the use of glazings with enhanced Ug-values and frames with enhanced Uf-values are a part of the solution, but are they enough? Or are alternative constructions needed to protect against mould?
The article discusses a variety of design principles for both placement and number of seals. Different types of spacers are also discussed. Depending on these aspects, and also on your edge overlap, different demands can be made.