Water gets heated in such giant boilers.

Mine is equipped with all the standard offerings, such as a solar-powered boiler, the subject of my last column.

In industrial settings, waste heat from boilers and large refrigeration units is sometimes recycled to reduce heating costs elsewhere.

Pipes convey hot water from the boiler to the radiators.

Then I lay there, listening to the boiler roar, and feeling the cool air on my face as it came through the half-open kitchen door, and the warm water on my body.