Bi-fold doors are a favorite choice for a door wall leading out to the patio, as you can then open the entire door wall for maximum air circulation and an unencumbered view. When it comes to choosing a door wall, you want to think about the material of the door, its overall size and appearance, and many other features. Note a few of those features here so you're sure to get bi-fold doors that work for your door wall and outside space.
A high-quality locking mechanism for your door may include a lock that requires a key to unlock from the inside of your home. However, be careful about this type of lock. This can mean trapping persons in your home in the event of a fire or other such emergency. It can often be better to opt for a bi-fold door with a locking mechanism that relies on a button or latch that you simply turn, like a deadbolt. If you are worried about security, invest in a thick, heavy-duty lock rather than a flimsy, lightweight aluminum lock that can be pried open easily.
The R-value of any material tells you how well it insulates an area. For a door wall, you probably want a very high R-value so you don't let heat or cool air escape out this area. Not all glass in bi-fold doors is alike; some will be thicker and offer better insulation, and some will be thinner and let in heat during summer or cold during wintertime. Wood frames may also be better insulators than most metals, but a door with a metal skin wrapped around a thick foam core may offer more insulation than most wood doors. Rather than choose a door by material alone, go by the R-value for the most insulation.
Note that a bottom track for your door wall may mean interfering with your view and traffic; that bottom track may detract from the look of wood floors or may mean a slight lip that makes the open doorway seem less attractive. However, without a bottom track, your door wall or bi-fold doors may have less strength and durability and may come out of alignment more easily. Note the weight of the doors as heavier doors may do well with a bottom track versus the look you want from your door wall when you're choosing the track design for your home.