The comfort of man is often predicated on how warm the shower or bath is. In the early days of our country, there were very few ways of obtaining hot or warm water: heating it over the stove or an outside fire. It is not hard to understand that baths were not really enjoyed in the colder months of the year. As always, necessity is the mother of invention and it was just a matter of time before man solved the problem of warm water. One of the earliest water heaters was the gravity fed heater which was no more than a large metal pot set at a high point behind the house. Logs were used to heat the water and the hot water was fed through a pipe with a spigot that was run through the window and into the kitchen.
The gas water heater was born when gas lines were established in the early cities. The gas that powered the street lights was run into the homes of the day and kept a fire under a water tank on the lower floor of the home. The early gas hot water heaters were not really very good as the best people could hope for was warm water. As the gas supply became better, thermostats were developed that allowed the gas water heater to be better regulated. Soon gas hot water heaters were in a majority of the homes.
A new form of gas was soon introduced to the rural areas of the country. Propane water heaters soon were the new kid on the block and they would rule in the farm country until the gas lines reached the farms. There are many places today where propane is still the fuel of choice for water heating.
Just when we think that everything has been invented along comes someone with a new idea. The new idea is the tankless gas water heater which heats water only as it is needed in the house. The tankless gas water heater is a complicated device that involves circulating water through a copper heat exchanger.