Original methods of heating a home in America, was done through multiple fireplaces throughout the house, this included having them on multiple levels in order to try and distribute the heat as evenly as possible. However, the Romans were the first to use radiant heat, the method was lost with the Romans for a while before finally emerging again late in the 19th century and was called “gravity heat”.
However, there were some drawbacks to using this method, the amount of time it required just to keep sufficient amounts of firewood on hand was full time job in of itself. Furthermore it required constant cleaning and maintenance of the chimneys and flutes to prevent fires that would burn the houses down. Unfortunately, during the early years, there were many houses that burned down from this, not to mention the hot ashes and cinders that burned throughout the night unguarded.
Eventually people discovered that they could use steam to heat houses and buildings, thus the Radiant Heat system was introduced. Radiant heat systems require a boiler to heat the water that flows through the system. Original boilers were heated from the same firewood used to heat fireplaces and the pipe system was relatively basic, relying on much trial and error, mostly error.
From these trial and error programs, post World War II, it was discovered that coal could be used in lieu of firewood, this did not require near the effort as chopping wood since customers could have it delivered to their own basement through a coal chute and it was fairly inexpensive. However, they were still in the trial and error phase of discovering the efficient radiant heat system, and one of the errors was finding out that boilers had a boiling point in which they would explode.
In warehouses, storefronts and other commercial buildings the radiant heat system was a series of the overhead pipes that distributed the heat throughout the facility as the pipes would follow all exterior walls and eventually make their way back to the boiler to be reheated. Most of these systems also had a pump system that assisted the steam to travel much more effectively in order to reduce the loss of heat.
Homes that were heated by radiant heat, typically had radiators throughout the system, generally in each room and under the windows that helped maximize their efficiency. Radiators were large heavy cast iron devices that would get very hot and had to have protective grates over them to prevent those in the house from receiving burns if they leaned against or touched them.
Later in the 20th century boilers were being heated from heating oil, this was even easier to operate and maintain than the coal system and delivery was much cleaner and more efficient as well. These systems required a oil tank to be installed, which was a gravity fed method to feed the oil to the boiler.
There are still some of these oil based boiler systems still in use today, fairly uncommon, but still in use there are even newer boiler systems available that run off of natural gas, propane and even electric. These systems are used in commercial buildings, residential applications have become more popular in the form of heated floors. The newer systems use heated water running through a network of special insulated pipes under concrete and tile floors, which also meets part of the new green energy drive.