Hi- extention just built (bar internal insulation, electrics, plasterboard). Rendered block, internal timber frame. 2 storys. 4.5m square.   New upvc white (cheapo, yes) french doors: I have terrible condensation on the outside panes, almost continually/ & daily (& pretty much all day too). Sun  now streaming onto them for 1hr -& remains directly on this West side till sundown- the windows/ glass is totally obscured bar the perimeters.   I do not have this problem