How Do Tankless Water Heaters Work?

Tankless Water Heaters are not storage tanks, like conventional hot water heaters. They heat the water directly as it is needed, instead of storing it for later use. This cuts costs by avoiding standby heat loss that comes with storage type water heaters.

How is This Done?

When you turn on your hot water tap, the cold water goes through a pipe, directly into the tankless water heater unit. This supplies a constant flow of hot water for your immediate usage. Instead of waiting for a storage tank to get full, then having to wait for it to be heated, hot water is supplied to you right when you need it. It is heated as it flows through the pipe into the unit. Typically, tankless water heaters provide hot water at a rate of two to five gallons (7.6 to 15.2 liters) per minute.

Choosing the Best Tankless Water Heater for You

Just like conventional water heaters, tankless units come in two types, electric and gas. They are both efficient, but there are some differences. Electric tankless water heaters use an electric component to heat water. While gas-fired tankless water heaters use a gas burner to heat water. Gas-fired units tend to produce higher flow rates than electric ones.

The size of the unit has a great impact on efficiency. Some of the smaller ones aren’t able to provide enough hot water when multiple uses are needed within the household. One example of this is when someone is taking a shower in the bathroom, while someone else is washing dishes in the kitchen at the same time. This can push the unit to its limit trying to provide hot water for this multiple, simultaneous usage. Here are three great options to help avoid this problem:

1. Install a “Whole House” unit that will be strong enough to provide hot water for every appliance in the home that needs it.
2. Install multiple tankless water heaters throughout the house, but connect them in a parallel manner so that they can work together.
3. Install a separate unit for each appliance that requires a lot of hot water for efficiency. For example, washing machine, dishwasher, sink, etc…

Other Tankless Water Heater Applications

Tankless applications are not just for everyday household appliances. They can also be efficiently used for providing hot water to other appliances that are not necessarily located inside the home. Here are a few examples:

• Remote BBQ pits
• An outdoor sink
• An outside shower
• A poolhouse
• Remote bathrooms
• Outside hot tubs
• Solar water heating systems
• Outside sanitation uses

Measuring Savings

If you and your family use less 41 gallons of hot water on a daily basis, a tankless water heater can be 24 to 34 percent more energy efficient that conventional hot water heaters. For homes that use a high amount of hot water, like 86 gallons per day, tankless units can be 8 to 14 percent more energy efficient. For an even higher amount of savings, install a tankless water heater at each hot water outlet located in or around the home. This can provide a savings of 27 to 50 percent.

For more information on tankless water heater flow rates, visit Plumbing with PEX for assistance.