In determining applications for replacement windows in listed buildings local planning authorities must take account of national planning policies, including those on the historic environment and supporting energy efficiency improvements to existing buildings. They must weigh up these policies and any other relevant considerations, including the relevant development plan, in considering each case.
Government guidance makes clear that conservation is an active process of maintenance and managing change. It recognises that heritage assets are likely to require sympathetic changes from time to time to ensure they remain used and valued.
Historic England publishes a range of useful advice on saving energy for owners of listed buildings and developers. This can be found online at: https://www.historicengland.org.uk/advice/your-home/saving-energy/.
I will meet my rt.hon. Friend, the Secretary of State for the Department for Energy and Climate Change soon but in line with the established practice under previous administrations, details are not provided on the topics discussed at meetings between Government Ministers.