Tankless Hot Water Heaters
“Another disadvantage of the tankless is that a hot water circulation system cannot be used. Therefore, you must draw water through the system until hot water reaches the tap. Heating costs go down, but water consumption goes up. The only way around this is to install a unit at each point where the hot water is used, and this is cost prohibitive and in most cases not even feasible.”
George, good morning and we would like to address your statement. In talking with Bill Morse of Yavapai Plumbing, a tankless water heater can be incorporated with a circulating system. Yavapai Plumbing installs a circulating pump with a timer and aqua stat. The way it works is when the water in the return line cools down, generally 10 degrees below set temperature on the tankless water heater, the aqua stat will turn on the circulating pump, in turn causing flow through the tankless which will move the hot circulated water through the recirculating system. The tankless water heater industry recognizes these methods of piping in a recirculation loop as acceptable so all warranties are protected. Kim and Bill Gagnon of The Plumbing Store informed us that there are tankless water heaters that can be plumbed and installed with a hot water recirculation system. Certain tankless units are made to be connected to a recirculation system and again, the warranty is protected and performance is not affected. George S. is correct with his statement that some tankless units cannot be used with a recirculation system and some homes do not require them. Most of the tankless units that The Plumbing Store installs are also plumbed with a recirculation system so you see they work with and without a recirculation system. Kim stated that in their home they have 8 people, 3 showers, 2 washing machines and 2 dishwashers and they never run out of hot water and their tankless is connected to a recirculating system. Keith Riggs of RED Plumbing is also in support of connecting a tankless into a recirc system and shared that to maintain the warranty you must first install a small 6 gallon water heater for the return line to circulate back to. This keeps the burner in your tankless from constantly running. Next you should have some sort of water conditioner system. If this type of system is installed you can run the recirculating hot water system to a tankless water heater and your warranty will be maintained.
George, we hope this answers your concern.