We bought a house which was remodeled in the early 90s and had an old Insinkerator in it. Not positive when it was installed but you could tell it was old but still worked, but it was so loud. It finally gave up the ghost and we decided to replace it with a newer model that was actually made for our septic system. This was super easy to install and is so quiet. Very happy with our choice, we would recommend this model to anyone with a septic system.