How Many Tankless Water Heaters Does Your Home Need?

If you are constructing a new home or upgrading your hot water system, then tankless water heater is a great option. Tankless water heaters offer a range of advantages over traditional water heaters, including greater energy efficiency, less maintenance, and a longer lifespan. They also take up less space a full tank. Aside from their higher initial cost, however, tankless water heaters do have one downside: reduced flow output when compared to traditional tanks. This can make it more challenging to select the right number and type of heaters for your home, but there are some simple ways to make this process a bit easier.

Two Configurations: Zoned or Whole House

Standard hot water heaters are designed to supply the entire house with hot water. Instead of having multiple units, you have a single hot water heater located in a central location. Demand is filled with hot water from the heater's tank. This configuration is necessary in part because tank heaters are extremely large and it would be wildly impractical to have multiple heaters throughout a house. Since tankless heaters are much smaller, the option of having on-demand near points-of-use is available.

In a zoned setup, multiple units are used to supply various "zones" or fixtures in the house. Individual heaters can be used to supply a bathroom with hot water, for example, allowing other units to supply demand for kitchen sinks or laundry machines. Multiple units can overcome the major downside of tankless water heaters, keeping flow rates consistent, even if there is heavy demand from multiple locations around the house.

Which is Right for Your Home?

Although tankless heaters can be zoned, they can also be installed in a central location in the same way as a traditional tank heater. In this case, you would likely choose a much larger and more powerful unit instead of the smaller units that are common in zoned setups. Cost and convenience are the two primary reasons to choose this configuration. A single, larger heater is often cheaper and much more convenient to install as a retrofit in older homes. The downside is that heavy demand can overwhelm the single unit, reducing the temperature of the water it can provide.

If cost and installation difficulty are not major concerns (or if you are installed heaters in a new home), then zoned setups are often more efficient. Your contractor can work with you to determine exactly how many heaters you need based on likely peak demand. By installing units in zones, you eliminate the risk of a central unit being overwhelmed by demand from multiple locations. If extra hot water is required in certain areas, then multiple, smaller units can be installed in series to provide extra water.

Making a Decision

Budget will be the primary driver of installation decisions for most people, with installation difficulty being a close second. Installing zoned heaters at points-of-use can be potentially disruptive and require significant modifications to a home, depending on the availability of gas lines or electrical drops. Despite the advantages, the extra cost and time required may not be practical or affordable. In this case, a central tankless heater is still an excellent option. Whichever configuration you choose, the benefits of tankless heaters make them well worth considering.