The book explains physical principles and mechanical design of household equipment and appliances, connecting theory to typical domestic practice. It surveys heating systems—steam, hot-water, and hot-air—covering boilers, radiators, ducts, vents, and temperature-control mechanisms, and provides operational and efficiency guidance. It details plumbing and sanitary arrangements, including fixtures, traps, back-venting, sewage disposal, and water-distribution piping. Water-supply chapters treat analysis, well construction, pumps, and treatment methods. Installation, proportioning, maintenance, and automatic controls are discussed with representative examples to illustrate practical domestic engineering solutions.