Hi lightairsky, thanks for your great questions! All Marvin windows can be tailored to suit your exact climate needs, so these windows can absolutely be a great choice in colder climates as the correct glass would be recommended to ensure best window performance. They do open - these are casement windows - and screens are certainly an option for this style.

Please let us know if we can help with any additional questions you may have. Thanks again!

How do you open these windows? What is the material of the windows?

Hi denicekatija, thanks for your interest in this project! These are Marvin Ultimate Casement windows, which crank open as shown below:

The windows shown above are wood-clad windows, meaning they have aluminum cladding over wood on the exterior, and wood on the interior. We happen to make the largest operating wood-clad casement window in the industry (36" x 102" or 44" x 91 1/8") if you are looking to bring tons of light into your home. Please let us know if we can answer any additional questions.

what size are the grills of the windows? thanks

Hi Bsquared Construction, we believe the simulated divided lites are 5/8". Thanks for your question!

Fantastic room and LOVE the windows! What style of divider/sticking was used?