Table 1. Summary of Typical Water Heater Costs and Efficiencies

Born fourth of five children to a merchant family in coastal Greenock, Scotland, on January 19, 1736, Watt was an ingenious modelmaker as a youth, being exposed to all the ship chandler's tackle and instruments, and was fascinated with natural philosopy, as science was called. His grandfather Watt was a very successful professor of mathematics in this remote locale. His mother's death when he was seventeen set his determination to pursue instrument making.

After nine years of some difficulty but considerable learning opportunity in London and at the University of Glasgow, while he was repairing a poorly built Newcomen engine for the university, he had the flash of inventive intuition that a separate condenser would greatly improve its efficiency. For this patented improvement, and its eventual technical and economic success, he is popularly credited with the invention...