Drafts or air-infiltration are year-round issues: in winter they allow valuable warm air to escape and unwanted cold air to enter; in summer, the reverse occurs. It is important to ensure that new thermal windows are installed correctly, without gaps between the frame and wall.
Once the window is screwed into position the gap can be filled with foam or tape. Most installers in Australia use PU-Foams to reduce air infiltration. Siegware offers products made by Ramsauer and blaugelb, including foams, tapes, guns and cleaners.
For more information see Products – Consumables – Installation.