Tankless Gas-fired Water Heater

On-demand gas-fired water heaters are tankless water heaters that differ from traditional hot water tanks because they don't require a storage tank. Instead, when a hot water tap is turned on, cold water flows into the heater and is heated by a gas burner. They can run on natural gas or propane and are available in a range of sizes to supply water to an entire house or at a specific point of use, like a shower or a sink.

On-demand gas-fired water heaters need to be connected to a gas line, and their combustion gases must be vented to the outside.</p><p>The heater must be large enough to provide enough hot water for your typical household uses. Sometimes, it can't provide enough hot water for multiple simultaneous uses. For example, taking a shower, washing clothes and running a dishwasher at the same time might be too much for a heater to handle and so the water might not be delivered at the desired temperature.

Because on-demand water heaters don't have a storage tank, there are no standby energy losses during periods when hot water is not being consumed. If you don't use a lot of hot water, then this can save a lot of energy compared to a hot water tank. However, be careful, because they also supply an endless amount of hot water and so it might be tempting to take longer showers, resulting in just as much or more energy use!

The earliest well-known prototype of an 'instantaneous' water heater was built in 1868 by Benjamin Waddy Maughan, a painter in London, England. It used a gas burner to heat water as it passed through pipes. Norwegian engineer Edwin Rudd improved on the design in 1889 and 1897, launching the first standard tank and tankless water heaters in the USA.