We run a dehimidifier all day, everyday through winter and it goes a long way towards keeping things comfortable. We still get condensation when the night time temperature drops below about 11 degrees, and I get thoroughly suck of wiping windows and frames every morning, but if it doesn't get done there is mould within 3 to 4 days. Was far less of a problem when we lived in Canterbury and the relative humidity was lower. However this year we purchased a Karcher window vac on the advice of a friend, and I have to say, it is bloomin fantastic and sucks up so much water. You can get them in Good Guys for around $100 or so.