I am installing a hot water recirculation system with a dedicated return line and a circulation pump at the water heater. There are two options for connecting the return line - the bottom of the water heater tank at the drain or to the cold water inlet at the top. I realize that unscrewing the drain hose bib can be a problem if it doesn't come out easily,i.e., it's only plastic and can break. If the connection is to the inlet, then an additional check valve is needed to prevent recirculation line hot water from feeding the cold lines when there is cold water demand in the house. What are the trade-offs?