Curtains are another great way to beat the chill. They come fully lined for a naturally snug and cosy feel to keep you warm.
You'll need to make sure there's enough room at the sides of your bifold doors for the curtains to sit neatly when they're fully open, so choose a header like wave or eyelet that is neat and compact, so the curtains don't take up too much space.
Or you could go for a single curtain that pushes to one side. It'll look amazing and won't get in the way when you want to step in and out.
Curtains can also help keep your home cooler in summer by reducing the amount of warm air transferred in, so they're a great solution to see you through the changing seasons.