The imminent introduction of EC ruling on the replacement window market might sound the death knell for the Georgian bar style so popular in the UK.
At the moment as of 1st. July all replacement windows supplied and fitted in the UK must have a Declaration of Performance certificate to verify that the complete window must have a “U” value equal to or better that 1.6W/m2k. However, using the usual knee jerk, stick a finger in the air type of calculation, the European Directive have decided that if the sealed unit has any form of spacer bar within the cavity the directive is that the U value must be increased by 0.1, because it might conduct a temperature transmission between the panes, even if it does not even touch the inner sides of the glass. So a simple vertical or horizontal bar may just pass scrutiny, but if your house has a full Georgian grid look, then forget it. As it stands, to replace the window with a comparable design would be illegal.