Hot Water Re-circulation System
When a hot water valve is opened in a home, the water in the hot water pipe has usually been sitting in the pipe for a while and is no longer hot. Anyone needing hot water opens the hot water valve and waits until hot water from the water heater tank reaches the fixture. In large homes, especially at the plumbing fixtures farthest from the water heater, this can take a while and the water running in the meantime is wasted.
Hot water recirculation systems circulate water in the hot water pipes, so that hot water will always be available and less water is wasted. This causes the water heater to run more, but how much more depends on the type of system. If the home uses a solar water heating system, this is less of a concern, since heating water is inexpensive or free.
Undersink System
This systems is typically used on retrofits but may also be installed on new construction. This pump is installed under the bathroom sink farthest from the water heater. The pump contains a sensor which switches the pump on when water temperature drops below 85°F and switches it off when water temperature reaches 95 °F. Newer pumps are adjustable from 77° to 104°.
In this system hot water is re-circulated intermittently. Hot water is returned to the water heater via the cold water pipes. This raises the temperature of the cold water slightly, but it returns to the usual cold temperature in a short time.
Hot water Recirculation System
This system can deliver hot water to fixtures quickly without waiting for the water to get hot. Rather than relying on low water pressure common in most water lines, recirculating systems use a pump to rapidly move water from a water heater to the fixtures.
Tankless Water Heaters Gaining in Popularity
Tankless water heaters have been in use in Europe and Asia for over 20 years.
They are just starting to gain wider acceptance and use in the United States.
Tankless water heaters are more energy efficient than traditional tanks because
they heat water as it is used, rather than heating and re-heating water in a storage tank.
They are also common in Europe and Japan in large part because they take significantly less physical space.
