We have condensation problems in two bedrooms - black spot mould in the cold spots and corners of the external wall/ceiling, and a build up of moisture on the windows (double glazed with trickle vents). The third bedroom is a small box room and doesn't seem to be affected at all. For a long time, we have periodically cleaned and painted over the affected areas to hide it. Now we’d like to completely redecorate the two bedrooms and buy new furniture, but before we go to the expense of doing so, we'd like to remedy the condensation problem. From research on the Internet, we're aware of mould eradication products and anti fungal sealants and paints etc, but we’ve also seen passifyer dehumidifying vents and whole house ventilation systems. We'd be interested to hear from anyone who has any knowledge or experience of any of these control methods or who can comment on the reliability and success as a condensation cure to help us make a decision. Any advice would be much appreciated.