House Beautiful architect tip: sash window dilemma

'I live in a Victorian terrace and am worried about my sash windows. They're 30 years old, single-pane, draughty and rattle in the wind. I'm not sure whether they need replacing or just refurbishing, but want to keep their period character if possible.'

Architect Gareth Bridge says: In terms of appearance, English Heritage says that repairing existing timber windows is better than replacing them, and that energy savings can be made by draught-stripping windows and installing better insulation elsewhere. For more detail, read Framing the View - Window Frames for a Sustainable Future by Lydia Wilson (available free at ni-environment.gov.uk). Many glaziers will replace existing glass with a thicker, more secure pane. In most cases, the extra thickness can be accommodated in the existing rebate - the slot in the frame that holds the glass. Double-glazed windows will be a bigger problem because the rebate would need to be increased, weakening the sash's joints. In this case the best option would be to employ a specialist firm.