mmf: ... Too much moisture on the windows in winter? The simplest solution is double glazing. Unfortunately it's the most expensive to retrofit. ...
E3xtc: well we are almost a week down now after having the ducted system put in and wow what a difference. I know that the temp of the days has dropped considerably since originally having the issue, but even when our son's room jumps up to 31 deg (like it did yesterday afternoon), we just pop the system on and the temp just comes down like a dream! Even on low fan speed the unit is pushing a real decent amount of air into the room; you get chilled ankles standing outside the door with the rush of air coming out from under it :P
Dynamic: I would get a quote for a heat pump to assist your decision.
They dry the air as they work