Abstract: An instant hot water delivery system for efficiently heating water when necessary to provide instant hot water to a faucet. The instant hot water delivery system generally includes a water heater including an inlet and an outlet, a cold water supply line introducing cold water into the inlet, a hot water supply line connecting the outlet to a faucet and a recirculation line connected to the hot water supply downstream of the outlet and the cold water supply line upstream of the inlet. The recirculation line forms a first recirculation loop for water within the water heater to flow during a first water heating process. A recirculation pump is connected to the cold water supply line between the recirculation line and the inlet for circulating the water during the water heating process. In one embodiment, the control unit is used to retrofit an existing gas or electric water heater.

Abstract: An instant hot water delivery system for efficiently heating water when necessary to provide instant hot water to a faucet. The instant hot water delivery system generally includes a water heater including an inlet and an outlet, a cold water supply line introducing cold water into the inlet, a hot water supply line connecting the outlet to a faucet and a recirculation line connected to the hot water supply downstream of the outlet and the cold water supply line upstream of the inlet. The recirculation line forms a first recirculation loop for water within the water heater to flow during a first water heating process. A recirculation pump is connected to the cold water supply line between the local recirculation line and the inlet for circulating the water during the water heating process.