The choice comes down to visual preferences, planning guidelines and budget. Eclipse Aluminium Windows are thermally and acoustically on a par with UPVC Windows, featuring exceptionally high security and even lower maintenance. The profile size of aluminium frames is much slimmer than in UPVC windows, so the overall look is more modern, sleek and streamlined, with more glass and less frame. This gives an enhanced, uninterrupted view through the window. Engineering tolerances are much smaller with aluminium than UPVC, so the frame looks tighter and more compact. Eclipse Aluminium Windows will continue to look their best with minimal effort, just an occasional wipe down with warm soapy water. As a more expensive material, aluminium windows do cost more than UPVC, but they will look fantastic for a lifetime. If you want replacement windows with slimline frames that will last for decades, then aluminium is the best choice.