These typically flop down after some years, and then the top sash won’t stay open. These are very difficult to fix, and once it breaks once, it’ll easily break again. Typically it’s time to get a new window.  ALL manufacturers of quality windows have shifted away from this technology. It’s now the best indicator of a junk vinyl window.

These are now the industry standard. You won’t see it looking like this on your window, you’ll see the brass coil uncoiled and stretched out. It never rusts and never loses coil strength. Great for double-pane small and mid-size windows.

3. HIGHEST QUALITY = BLOCK & TACKLE BALANCE MECHANISM

You’ll see a thin white nylon cord. The most expensive Pella and Andersen windows use these, including the venerated and very expensive Renewal By Andersen series. This technology is now filtering down to vinyl windows, although some are resisting and saying that constant force is better. It’s not, it’s just cheaper for the factory. Block & tackle operate with the most ease, and they can handle heavier window sashes than the constant force mechanism, including large window and triple-pane. THE OKNA SERIES USES BLOCK & TACKLE