I have some double glazed, aluminium framed windows in my flat that are a source of many headaches due to the issues they cause with condensation. I believe the frames have some form of cavity construction but the internal metal surfaces get very cold and this results in large build-ups of condensation on these internal surfaces (which then runs onto the surfaces/carpets below). I'd love to replace the windows for UPVC units but the special circumstances of my flat means that replacement is not an option. I'm at my wits end as to what I can do to solve this issue. I was wondering if there's anyway of injecting some form of insulating material into the cavity of the framework to help or any paintable covering that could coat the painted metal but I don't even know if this would be effective. I appreciate the general advice of good ventilation and possible use of dehumidifiers, but this doesn't overcome the route problem which is the cold metal. Does anybody have any advice for me please??