7.7 The SPD may need to be a bit more flexible on the use of modern materials for windows and doors. Heritage metal frames are already widely approved in Conservation Areas and 'Heritage' designs in UPVC widows are almost indistinguishable with narrow glazing bars and butt joints from timber originals. Without obvious aesthetic blemishes, the benefits they offer in energy saving, insulation and security outweigh the retention of less effective alternatives. After all, inhabitants of wattle and daub cruck-framed cottages didn't hesitate to infill with brick and swap shutters for glazed widows when the technology became affordable.

7.7 Current circumstances concerning energy efficiency and carbon reduction make resistance to non-traditional materials unrealistic. Significant improvements have been made in the design of various ‘heritage’ ranges of UPVC, metal and composite materials to make them more acceptable to use in locally listed buildings. It is also unrealistic to deter homeowners from making their homes and offices warmer, less costly in upkeep. The building may be a 15th Century cruck-framed cottage but subsequent generation of owners will have replaced wooden shutters with glazed fenestration at some point in the past. It would be better to phrase the guidance more positively. ‘Although timber joinery is preferred, the Authority will consider on a case-by-case basis the use of modern materials. The designs, whether UPVC, metal or composites, should blend with the listed building and offer significant energy efficiency gains. Designs that offer solar gain and heating from ground or air will be judged on a similar basis.’