Tankless or instantaneous water heaters have recently been introduced for domestic water heating in American homes. They have been popular in Europe for some time. What are they? Do they provide instant hot water? Are they a good deal?
As you’d expect, a tankless water heater isn’t built like a typical water heater. It doesn’t store a tank full of hot water. The tankless system heats water as it flows through a heat exchanger. A relatively large burner modulates the size of the flame to match the water flow for an even discharge temperature.
Tankless water heaters are complex systems designed to evenly heat water at various flow rates. They require a special stainless steel vent and a large natural gas line. They also require routine maintenance – you need to acid-flush the heat exchanger to remove deposits. The installed cost is about five times the cost of a standard tank-type water heater.
Do they provide instant hot water? No, the water in the pipe to the fixture will still be cool, just like water from a standard water heater. They instantly heat water as it moves through the system. Do they save money? Yes, but it may take 10 years of savings to make up for the higher installation cost.