The first steam radiator patented for in-home use was invented in 1862. The very first steam radiator was invented in 1831, but the system had too much pressure for in-home use.
The first successful in-home steam radiator was invented by the partnership of three American inventors: Angier Marsh Perkins, Joseph Nason and Robert Briggs. A later design addition, the Bundy loop, was introduced by Nelson Bundy in 1872. All of these early systems were built with steam valves which would spontaneously release as pressure built up in the system. Early steam radiators were constructed with cast iron steel and relied on a boiler to heat water and push the hot water through the pipes.