Spring bronze works well on wood windows. If you have steel windows, metal weatherstripping is more complicated. There are resources on B+B for both. The advantage of metal weatherstripping is that it is a long-lasting solution. Using foam or plastic strips will help, but they will have to be renewed periodically. A product that works very well is Mordite rope caulk that you press into place where the sash and frame meet. I use this as a supplement to the metal weatherstripping. The combination totally eliminates any air incursion around the sash. Mordite can be removed easily when you want to open the window. But I have had it last several years on unopened windows.
Spring bronze works well on wood windows. If you have steel windows, metal weatherstripping is more complicated. There are resources on B+B for both. The advantage of metal weatherstripping is that it is a long-lasting solution. Using foam or plastic strips will help, but they will have to be renewed periodically. A product that works very well is Mordite rope caulk that you press into place where the sash and frame meet. I use this as a supplement to the metal weatherstripping. The combination totally eliminates any air incursion around the sash. Mordite can be removed easily when you want to open the window. But I have had it last several years on unopened windows.