Buildings within conservations areas, including houses, are under regulations to protect their historical beauty. For example, you couldn’t remove original timber windows to replace them with standard uPVC ones as this wouldn’t fit in with the look or heritage of the building.
Most planning officers won’t allow uPVC windows to be installed in houses within conservation areas but Residence 9 is an exception. R9 is sympathetic to a building’s original appearance and the traditional features help it achieve an authentic 19th century flush sash timber window look.