You will need permission under Article 4 of the Conservation Order to replace your windows. Milton Keynes Council is unlikely to grant permission for sash windows to be removed and replaced with UPVC windows.

Where original, your windows will be painted wooden sash windows. Never scrap original sash windows before checking that they cannot be renovated. Common faults are draughts, ‘rattling’, or rotten bottom rails, which can be repaired by a good carpenter. You should not need to replace the complete window.

Original windows will have rolled or cylinder glass, often thinner than modern float glass. If modern glass is fitted adjustment may be necessary as sash windows are dependent on the right weight of glass to slide/work properly.

Ideally, to keep wooden windows in good order, they should be repainted every 5-7 years

There is information in the Library about local carpenters/joiners who can repair or replace sash windows. If your house has substitute plastic windows, when these deteriorate, please consider replacing them with wooden sashes.

Many street and roads have examples of original sash windows