Timber window manufacturer Mumford & Wood says English Heritage is contravening the government’s new Green Deal scheme by refusing to allow modern double-glazed energy-efficient timber windows to replace single-pane originals on listed properties.

The much-vaunted Green Deal, which offers tax cut incentives for thermally efficient homes, is at odds with the “defiant” position being taken by many council conservation officers under English Heritage guidance, according to Mumford & Wood.

Mumford and Wood accused them of having a “head-in-the sand” position.

“Properties with single-glazed windows and ill-fitting doors can be a misery for owners and outweigh the pleasure of living in an aesthetically beautiful Georgian, Victorian or Edwardian property,” said Mumford’s sales and marketing director Chris Wood.

“The need to upgrade these properties as demanded by Government policies should be high on the agenda for the comfort of their occupants as well as to contribute to the UK’s targets of an 80% reduction of UK carbon emissions by 2050 (over 1990 levels).

“To meet these targets domestic emissions from residential buildings need to be cut by almost 30% over the next decade.”

One Mumford customer recently lost her fight to upgrade her windows with Mumford & Wood high- performance timber windows in order to improve insulation and cut out traffic noise.

“Conservation organisations should conform to sensible, national guidelines that allow replacement within a framework of tolerances, and not leave it to the personal discretion of an individual to make an ill-informed decision,” said Mr Wood.