This 90 tube system was installed in 1998 in Victoria, BC. It was flush mounted with the concrete tile roof. It heats about 3000 sq. ft. of radiant floor in this straw base construction house. The Domestic Hot Water uses an SST 120 Triple Coil Stainless Steel tank, with the solar going to the bottom coil, an electric boiler to the middle coil for backup, and the radiant floor drawing heat from the top coil.