Does attaching aluminium foil to the inside of double glazed windows cause mildew?
You could damage the seal inside the double panes with the foil “bouncing” the rays back while the rays are also beating in, making the inside of the vacuum too hot. Remove the aluminum foil. It is close to autumn now and not needed anyhow. If you don’t want the sun’s rays shining in, pull the shade down or install a tinted plastic on the windows. I don’t think mildew would be a factor in using the foil because it would be too hot for it to grow. It looks “tacky” anyhow.
