For private dwellings within a conservation area, typically you won’t require permission to change your windows. However, we would suggest contacting your conservation officer before proceeding.
IF your property is covered by an Article 4 Directive, or has any commercial elements (including rental), permission probably will be required. Again, contact your local authority conservation officer before proceeding.
For listed buildings, planning permission is always required. Listed status looks at traditional materials as well as aesthetics, meaning that uPVC is unlikely to be permitted except in special circumstances.
In instances where maintaining the traditional aesthetics is of the utmost importance, we would recommend our Heritage Rose and Ultimate Rose sash windows. Both are virtually indistinguishable from timber and have already been accepted in numerous conservation areas including Torfaen Council, Isle of Wight Conservation and Lake District National Park.