Period homes deserve windows that respect their heritage while delivering modern performance. The most important choice is the style: sash windows for Victorian and Edwardian properties, casements for 1930s semis, and bay windows to preserve original frontages.
uPVC has come a long way - modern woodgrain finishes are virtually indistinguishable from timber and offer far better insulation. Aluminium slimline profiles are a great option where you want to keep sightlines narrow.
Whichever material you choose, look for A-rated energy performance, multi-point locking and a proper FENSA-registered installation.