Commercial system layout. The DeltaSol MX operates a metered energy supply of Hydronic space heating and DHW for 2- apartment townhouse. Solar closed loop system consists of 2 loads: DHW, heating Buffer storage. The back-up of Space Heating and DHW is provided by a single stage Boiler pre-heated by solar Buffer storage tank. Home distribution incorporates 2 hydronic heating circuits (HC) controlled by floating action 3-way mixing valve with temperature compensation using Outdoor Reset and Indoor temperature Feedback. The DeltaSol MX provides Warm weather Shutdown (Summer Mode), boiler differential and 7-day independent programmable Setback control. Energy use for heating and DHW consumption volume is metered separately for each dwelling.