An air to water heat pump system is configured to minimize operating cost of the system utilizing one or more of hot water demand patterns, present or predicted ambient conditions, and/or electrical power cost. The system may be configured to reduce production and/or storage of hot water during periods of low demand, and increase production and storage of hot or hotter water immediately prior to a period of predicted high demand for hot water. The system may be configured to take into account ambient weather conditions to increase production and storage of hot water during favorable ambient conditions, and/or to increase production and storage of hot water prior to predicted cold ambient conditions.

A controller for an electric booster element in a water heater is described. The electric booster element is powered from mains power and the controller comprises a control module and a capacitive module adapted to store power and supply stored power to the control module. The control module produces a control signal for controlling a relay to supply or restrict mains power supply to said booster element, said control signal depending at least in part on time of use data.

A controller for an electric booster element in a water heater is described. The electric booster element is powered from mains power and the controller comprises a control module and a capacitive module adapted to store power and supply stored power to the control module. The control module produces a control signal for controlling a relay to supply or restrict mains power supply to said booster element, said control signal depending at least in part on time of use data.

Object of the present invention is an electric water heater with a vertical development storage and upper and bottom resistive heating elements and possibly a lower heating element consisting of the condenser of a heat pump. The water to be heated enters the bottom portion and is drawn from the upper section. The water heater is configured to operate in different heating modes selectable by a user, wherein all the modes guarantee to meet a set temperature but different by control logic and consumption level and is further able to have flexible consumption depending on a condition of the power grid.

Object of the present invention is an electric water heater with a vertical development storage and upper and bottom resistive heating elements and possibly a lower heating element consisting of the condenser of a heat pump. The water to be heated enters the bottom portion and is drawn from the upper section. The water heater is configured to operate in different heating modes selectable by a user, wherein all the modes guarantee to meet a set temperature but different by control logic and consumption level and is further able to have flexible consumption depending on a condition of the power grid.