steam rising from hot water in a sink

Tankless vs Recirculating Hot Water Systems

When selecting a new water heating system for your home, it can be helpful to take your household needs into account. Did you know that depending on the size and fuel source for your hot water tank, you may be waiting up to 1 hour and 20 minutes for water in the tank to reheat? When you have a busy household with a high demand for hot water, this wait can be frustrating. Below, we have explained two common solutions to this problem often referred to as instant and on-demand hot water.

On-Demand Hot Water

Tankless water heaters heat water on demand, without the use of a large storage tank. When a hot water tap is opened, cold water enters the unit, and a gas burner or an electric element heats the water. As a result, tankless water heaters deliver a practically endless supply of hot water. Typically, tankless water heaters provide hot water at a rate of 2–5 gallons per minute, though there are larger units that can deliver 11 to 13 GPM.  The larger units are definitely much harder to retrofit and must be considered while the house is being built. Even the largest, gas-fired model cannot supply enough hot water for concurrent, multiple uses in larger homes, however. For example, taking a shower and running the dishwasher at the same time can stretch a tankless water heater to its limit. To overcome this problem, homeowners sometimes install two or more tankless water heaters to satisfy heavier demand. We’ve written more about tankless water heaters here

Instant Hot Water

A hot water recirculation system is a plumbing system that keeps hot water generated by your traditional water heater near the fixtures, so when a hot water tap is opened, access to hot water is almost instant. There are two types of systems: dedicated and integrated.

Dedicated Loop:  The circulation pump for this system is mounted on a pipe connected to the water heater tank down low. This is the cooler side of the loop, or the return. The hot water pipe is installed in a loop throughout the home, passing near each plumbing fixture. At each fixture, a short pipe connects the loop to the hot water valve. Because hot water is constantly circulating through the hot water loop, any time a valve is opened, it takes only a fraction of a second for hot water to reach the valve.

Integrated Loop:  This system is typically used on retrofits but may also be installed on new construction. It consists of a pump installed under the plumbing fixture farthest from the water heater. In this system, hot water is re-circulated intermittently and hot water is returned to the water heater via the cold water pipes. While this raises the temperature of the cold water slightly, it returns to the usual cold temperature within a short time. 

Between the cost and the number of choices, it can be overwhelming to decide on a new hot water system for your home. At North East Air Conditioning and Plumbing, we are here to help you understand your options and answer any questions you may have. Reach out to us today online or give us a call at 210-658-0111.


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