Both make quality windows. I would look at the u value and SHGC, lower the better.

The technical factors will be very different since they both use the same glass manufacturer. The differences will be warranty and construction of the window. Pella is a wood window with an aluminum cladding on the exterior, while Andersen uses a vinyl skin on the exterior to protect the wood interior. From what I see in my market- east coast- the vinyl cladding holds up much better than the aluminum. The aluminum cladding of the exterior of the Pella is prone to separating from the wood on the sash, allowing moisture to react with the wood...


I do work for Andersen- full disclosure- but am honestly commenting on what I see in the field when a homeowner is replacing problematic windows.