For instance, 1L means that the panel door is hinged on the left, and as such pivots on the left. This left is determined as you stand in the room looking at the shutter. As you might expect, 1R applies to the right.
Bifold is a shutter configuration term used to describe the process of hinging two shutter panels together - so that when the panel doors are open - they fold back on each other and swing together away from the window.
You will usually see this bifold configuration in larger windows requiring four or more panels. We have also had customers utilize this configuration on their sliding doors. These configuration decisions are driven by panel weight. Every manufacturer has different warrantable standards based on the weight restrictions of their wood or poly. For most manufacturers, the width range is generally between 24" and 36" per panel. So, for a 94" window, you would have two panels left and two panels right - and both sides would bi-fold.
As you might imagine, maximum allowable panel width drives configuration choices. Why does this matter? Because, the fewer panels you have in a window, the more light and outdoor view you can preserve. Therefore, if you have a 35" wide window - depending on the manufacturer - you will either have one or two panels in your window. One panel provides a more open look - while two panels are far less open, but will provide a different design look.
From this basic understanding, the configurations can really get wild - with the introduction of T-posts. T-posts are vertical wood supports placed at certain locations which provides support for panel hinging. With the use of T-posts - shutter configurations can grow to hundreds of inches in width - accommodating the biggest windows - and many panels.
With any luck, these few insights have helped you glimpse inside how the industry configures shutter panels and what constraints we consider. We have done lots of different configurations over the years, and would love to help you with yours. Also, be sure to check out our online shutter cost calculator for a rough price estimate.