Tankless Water Heater History
The first tankless water heater was invented by an Englishman named Maughan in the 1870s. The idea of tankless water heater is to heat the water only when you need it and almost instantaneously, so no storage tank of hot water. Like many inventions tankless water heaters went through many designs over the decades.
Most of the tankless water heaters were designed to be used at point of use. That is that wherever you needed hot water you would install an electric or gas powered unit and have hot water at the point you needed. This reduced also the plumbing of a house since you didn’t need to run another water pipe for the hot water.
Typically you had a small unit in the kitchen; the unit incorporated the kitchen faucet and maybe a very small tank of one gallon or so. Whenever you turned the hot water faucet open you would get hot water automatically after a few seconds.
In the bathrooms you had larger units, mostly gas operated that would do the same. No tank and no constantly heating water and with excellent efficiency that would remain largely the same. Efficiencies of 80 plus percents were common. Since there isn’t a storage tank of water with its associated standby heat loss the overall efficiency would be much higher.
Compared to storage tank water heater where you heat the water and keep it hot the tankless water heater heats the water only once for immediate use with higher efficiency. This goes for electric tankless water heaters as well as for gas tankless water heaters.