Lived and worked there for 16 years Warm air heat & AC not done by plumbers, pipework copper soft under slab, rigid above CPVC (solvent weld plastic) & polybutelene (plastic with crimped copper fittings) (which has now been banned but tons of it around). Waste water Sch 40 ( thick) solvent weld soils & wastes then sch 20 (thin) once it exits property separate vents on more or less everything although only 1 1/2 "or 2" every thing imperial Electric unvented cylinders, 2 immersions, gas in town. terminology was the worst part, i remember standing in a "supply house" (merchants) trying to buy a 4" swept tee, after a few jokes about my accent and a trip into the warehouse was told i needed a "4" combo". My experiance was in the South, i know in the northern states they have heating and water systems similar to ours, boilers (furnaces) no radiators its all skirting heating or warm air