Abstract: Fenestration unit monitoring apparatus configured to retrofit an existing fenestration unit to incorporate components that are capable of monitoring the locked or unlocked status of the existing lock assembly and/or the panel position status of a movable panel of the fenestration unit. The fenestration unit monitoring apparatus described herein may provide a relatively easy and aesthetically pleasing option to monitor the lock status and/or panel status of an existing fenestration unit with an existing lock assembly already located thereon. The fenestration unit monitoring apparatus may be inserted into an existing lock assembly slot in a frame member of an existing fenestration unit that already contains a lock assembly without requiring removal of the lock assembly from the lock assembly slot.

Abstract: Fenestration unit monitoring devices described herein are configured to retrofit an existing fenestration unit lock assembly to incorporate components that are capable of monitoring the locked or unlocked status of the existing fenestration unit lock assembly and/or the panel position status of a movable panel of the fenestration unit. The fenestration unit monitoring devices include a monitor housing configured for mounting on the surface of a frame member on which a fenestration unit lock assembly is already mounted. The monitor housing of the fenestration unit monitoring device includes a lock cavity such that a portion of the fenestration unit lock assembly is located in the lock cavity formed between the monitor housing and the surface of a frame member to which the monitor housing is mounted.