Frame fungi on insulated windows.

Insulated windows (fixed triple glass window elements), became common in Finland during and after the energy crisis. Moisture tends to condense along the edges causing mold growth on the frames. Nine houses with insulated glass windows and eight with other types of window were studied. Fungus samples were taken from the window edges and from the inside air and cultivated on malt extract agar. In five of the houses with insulated windows there was visible mold growth on the window edges. The predominant fungus was Aureobasidium pullulans. With other types of windows there was only one case of visible mold. The concentrations of fungi were about the same in the air of houses with both types of windows. Aureobasidium was rare in the air samples. Thus, window frame molds seem to contribute very little to airborne fungus concentrations. In situ trials were done to control the mold growth with disinfectants. Repeated spraying with aldehydes or quaternary ammonium chlorides in alcohols proved to be successful.