In my opinion these windows are effectively designed to rot. The "clad" is just clipped on. There is no attempt at a water seal. All the "clad" does in these windows is wick water into the interstitial space between the aluminum and the wood and then hold it there. Especially true of the bottom section. The "brilliant" comments about painting are patently silly. You cannot seal the clad with paint as the coefficient of exapansion is different than wood and this will crack any seal at the first major temperature change. To be successful, these otherwise nicely designed windows need to have something to seal the clad. This is the exact same problem that people who buy old wooden boats and then try to cover them with fiberglass run into. They just end up sealing the water in where the bacteria have a field day.