The right window is not determined by one universal winner. Frame material, glass, opening size, hardware, exposure, installation quality and maintenance expectations all matter.
Real project imagery for context.
These images come from the current KAINOS project library and are included to show the visual language of residential, commercial and design-stage work.



uPVC
uPVC can suit homeowners who want a low-maintenance frame with a softer appearance and good everyday performance. It is commonly used for sliding and casement applications in residential work.
ALUMINIUM
Aluminium frames can offer a slimmer visual profile and can be useful for larger openings or a more minimal architectural language. The exact system and thermal treatment should be assessed with the fabricator.
GLASS MATTERS TOO
Comparing frames while ignoring the glass can be misleading. Solar exposure, acoustic requirements, privacy and safety all affect the appropriate glass specification.
INSTALLATION IS CRITICAL
A high-quality frame installed badly can still leak, bind or allow air and water infiltration. Accurate openings, fixing, sealing and finishing are part of the window specification.
ASK FOR A COMPLETE SPECIFICATION
Compare frame system, profile, glass type, hardware, mesh, colour, warranty and installation—not just “uPVC” versus “aluminium”.
Use the guide with your actual project documents.
Online guidance can help you ask better questions, but the final construction scope should be based on the actual plot, drawings, engineering requirements, selections and project-specific BOQ.