I think the main advantage of these windows isn't heat retention, but how practical and space-saving they are. They help you save a ton of space. Of course, Slider Windows come in different types, just like any other windows, and their insulation depends on the design, the quality of the seals, and the installation. I wouldn't rule out this option just because of cold winters, since it's absolutely possible to install these windows even in colder climates. But I also wouldn't choose them based on looks alone. So it's worth doing a bit more research and learning about the technology.