Hot water takes too long to arrive

Hot water travels at the speed of the water in the pipes, and every metre of pipe between the heater and the tap must fill with hot water before the tap runs warm. A 3/4 in supply line holds about 1.5 L per 10 m, so a 30 m run can mean several litres of cold water to clear, which at a normal tap flow is tens of seconds. The heater is working correctly the whole time.

The pattern confirms the cause: if the water arrives hot once it finally comes, and the wait grows with the distance from the heater, the fix is distribution, not a bigger heater. If the water arrives warm but never hot at one fixture, that is a different fault (a mixing valve or a crossed connection).

Three honest options exist. A recirculation system keeps hot water moving through a return line or crossover valve so the pipe stays warm and the wait drops to seconds; it adds cost, gas use and, on a timer, tuning. A point-of-use heater at the distant fixture heats locally for that sink. And insulating the hot-water pipes reduces cooling between draws, which shortens the warm-up after idle periods but does nothing for the initial cold slug.

Tankless units add their own few seconds of firing time, which is why the wait on a tankless system at a far tap can feel long even with recirculation; Rinnai and Navien document recirculation modes for exactly this reason.

Slow delivery is a fault when it is new, one-sided or never hot: a single tap that ran hot quickly and now runs cold for minutes points at that fixture's valve or a shut-off; a whole-house wait that suddenly doubled points at a partially closed main or a failing mixing valve. A technician tests rather than guesses, and the diagnostic fee CANRO publishes is credited toward the repair if you proceed.