US Patent 10317247 Fenestration unit monitoring apparatus with tethers and methods

The fenestration unit monitoring apparatus with tethers are 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 include a lock status sensor located on a tether such that the lock status sensor can be positioned within an existing fenestration unit lock assembly when a monitor housing of the fenestration unit monitoring apparatus is located on the fenestration unit adjacent the fenestration unit lock assembly.