Hot water delay depends on the piping size and distance from the water heater to the fixture. It’s a common misconception that a tankless water heater installed in the place of the water heater will eliminate this hot water delay. Running water waiting for hot to arrive is a waste of water and energy. Water is precious and will become more scarce in the future in California. Minimizing hot water wastage is important. Good hot water piping design can help hot water delay in both new construction and retrofits.
In single story houses, it is often possible to greatly optimize the design of an existing hot water system by locating the tankless water heater in a different, better location.
In two story homes with fixtures on both floors it is not possible to relocation the tankless for shorter hot water delay. The tankless must go in the location of the existing water tank. In this case, a small (football size), under-sink, retrofit demand, (push button or motion sensor activated), recirculation pump can be used to eliminate water wastage. We recommend and install the Metlund system because of its high quality components.
If you home has a hot water recirculation return system, it will work the tankless. Some tankless manufacturers lower the heat exchanger warranty with continuous recirculation systems. We often install a battery backed-up timer to enable recirculation between, say, 6 am to 9 am, and 4 pm to 8 pm, with an aqua-stat to save gas and energy. Continuous recirculation systems save water but carry an energy penalty. That is why Tanknot Tankless Inc. prefers demand recirculation instead. Existing recirculation systems can be converted to demand recirculation with no reduction in the tankless warranty.