There is provided a space heating system (100) that includes a heat pump (105), a supplemental gas heating system (110), and a controller (115) connected to the heating system (100). The controller (115) controls a switching set point, which in its simplest case is an ambient temperature at which the controller (115) switches between operation of the heat pump (105) and operation of the supplemental gas heating system (110). The controller (115) is connected to a real time source of information (195) providing at least one of current electricity prices and current prices of a source of heating such as gas, and changes the switching set point in response to changes in at least one of the electricity prices and the gas prices. There is also provided a method for control of the heating system (100).