Compare complete windows
Request information for the complete window and the quoted dimensions. Establish which glazing and profiles are included in that information. This provides a more useful basis for comparing quotations that specify different systems or frame arrangements.
Include ventilation
Replacing windows can change air movement within the home. Discuss how fresh air enters and moist air leaves. Have window ventilation and any existing mechanical system considered together, especially when other improvements to the home are planned.
Prepare the joints
A carefully specified window still needs suitable connections to the facade. Discuss air sealing, insulation around the opening and finishing before installation. Ask who is responsible for these elements and how their execution will be checked.