Does anyone know if there is an easy replacement for the Autoflo 97 humidifier. The existing return duct opening is 7” high by 7-3/4” wide. I’m hoping not to have to modify existing opening in return duct. It’s a bypass type humidifier. The overall space I have at the location of the humidifier is 15”x 15”. Is there a good replacement humidifier out there?? Thanks much.