A hydronic heating system for a building includes condensing and non-condensing boilers in a hybrid arrangement. A control apparatus receives information from one or more condition sensors, such as air temperature or water flow, and calculates heating load requirements. The control apparatus then independently selects and operates the various boilers of the system to optimize boiler efficiency and operating characteristics. The independent operation of said first and second boilers is modulated as a function a comparison of a heat load assignment for the and second boilers to a heat output of the first and second boilers.
