Since installing Shepherd Filters, our system has been kept perfect throughout. I have inspected it myself a number of times thinking I will find grease in the ducting and inside the canopy due to the cooking we do, but it’s still perfect, 100% clean. It’s the best filter we have ever had as the others got very greasy, which meant we had to clean them 2 or 3 times a week and a couple of weeks after the deep cleans it was already getting greasy again. This saves us money on deep cleans and hours cleaning the filters during the week. We are very happy to recommend it!