A heat recovery system arranged to heat water includes at least one heat exchanger (9) arranged to heat water by heat exchange with waste heat. A storage reservoir (11) is arranged to store water heated by the heat exchanger (9). The heat exchanger (9) is switchable between a first mode of operation in which water is circulated by a pump (12) in a circuit that includes the storage reservoir (11) and the heat exchanger (9), and a second mode of operation in which water is circulated by the pump (12) in a circuit that by-passes the heat exchanger (9). Heated water of at least a desired minimum temperature can be supplied to at least one outlet during both the first and second modes of operation.
