I have just viewed a 4 bed home in Gloucestershire built by Redrow in 2011. It has double glazing throughout and the frames are hard-wood frames. Alas there are no trickle filters (those filters located above the window, but within the frame that allow air to pass through). Should I be concerned re: condensation? Can trickle filters be put in by a decent workman (or even me?) at a decent price?