To insulate old windows, apply weather stripping around the edges to block drafts. Use caulking to seal any gaps or cracks in the window frame. For additional insulation, install window film or thermal curtains to reduce heat loss and improve energy efficiency during colder months.

Old windows can be insulated with weather stripping and caulking. Adding window film or thermal curtains helps improve insulation and prevents heat loss, making your home more energy-efficient without replacing the windows.