A furnace makes heat, a boiler makes steam or hot water. Many small buildings have a boiler that does all three by combing components in a single unit. Large buildings have three separate units, and more for specialized tasks. In New York City, there is an important distinction between cellar and basement. Cellars are not habitable while basements are. The building code definition of a basement is that at least half its height is above street level, and that of cellar is that just over half its height is below street level. Many residential buildings are designed to take advantage of that distinction. The rule covers sloping site conditions to average the difference between front and back. The basement level is often called the Ground Floor to take away any stigma associated with basement. Much mechanical and electrical equipment is located in the cellar to maximize habitable space above. Same goes for the roof. Terrific expenditures for excavating multi-level cellars are the norm for high-rise buildings -- even in hard rock as in Manhattan -- to produce maximum habitable space allowed under the zoning code, which, in combination with building health, and environmental codes, regulates bulk, height, light, air, room sizes, window sizes and a host of requirements for barely tolerable human habitation -- and legal standards are ever dropping in squalid, squirming cities for luxury as well as dirt cheap holes. We architects are expected to, well, cheat, to maximize what property owners want at the expense of building inhabitants and the inccreasingly squeezed and violated public. What helps us get away with cheating is massive PR by our professional flacks, sophisticated aesthetic and environmental theories that claim wretched architecture is beautiful, drunken orgies with regulatory officials, revolving door participation in standards committees and holding public office -- to be sure, as practised by all professions, in particular those that are solemnly licensed and sworn to protect the public from people like us. Occasionally an idiot architect, like this one, tries to go against the grain, and work dries up instantly and family says dont be stupid, dont shame us. Then back to doing what church and family command to be an outstanding citizen/bandit. Social planning is a useful deception, twinned with the free market -- the two backed beast.