Lower Water Heating Costs in Your Building: Use Tankless Systems

Water heating can account for 25 percent or more of the total energy consumption in a home, and in a commercial setting, this total can be much more. When looking for ways to lower water heating costs in your building, consider replacing traditional tank-style water heaters with more efficient tankless systems.

Advantages of a tankless water heater

Tankless water heaters, sometimes called instantaneous or demand water heaters, produce hot water when it’s needed. They use a gas burner or an electric heating element to heat water as it flows through the system and to the faucet. They offer several advantages that can lower water heating costs over a traditional tank-style water heater:

• Ongoing supply of hot water – Unlike heaters that heat water and then store it in a tank until it’s used, tankless models produce hot water as needed. The system produces hot water constantly, and as long as the heating system continues to work, you won’t run out of hot water.
• No tank needed for water storage – With tankless models, there’s no tank that can run out of hot water in the middle of a task, leaving you standing in a cold shower or wondering how you’re going to finish cleaning the dishes. The amount of hot water the system can produce is limited only by the capacity of the system, not by the amount of water that can be kept in a tank.
• Increased energy efficiency – Standard models heat water and store it in a tank until it gets used. While sitting in the tank, the water can lose heat energy and cool off. Before it can be used, it must be heated again. In this case, you’ve lost energy and money heating water that didn’t get used, and then wasted an equivalent amount of energy and money reheating the water to an acceptable temperature. This type of loss doesn’t occur with tankless water heaters. Tankless units can significantly reduce energy loss and decrease your water-heating expenses by up to 50 percent.
• Reduced space requirements – Tankless water heaters are much smaller than tank-style units and can be more easily installed where needed. If indoor space is limited, there are tankless models that can be installed outdoors.

Sizing a tankless water heater

To effectively lower water-heating costs with tankless units, you must size them correctly. In other words, the tankless units must have enough capacity to provide the amount of hot water you need when you need it. Keep in mind two important sizing concepts: flow rate and temperature rise.

1. Flow rate – Flow rate is the number of gallons of hot water needed every minute to accommodate your facility’s highest level of demand. In a commercial building, flow rate could be substantial. Determine total flow rate by estimating which hot water devices are most likely to be in use at the same time. Add up the total gallons of hot water used by these devices in bathrooms, kitchens and other areas throughout your facility. This number is the flow rate that your tankless water heaters must produce.
2. Temperature rise – Temperature rise is the temperature difference between water coming into your building and the temperature you want the water to be when it’s used. For example, if water coming out of your utility connection is 50 degrees and you want hot water in your building to be 120 degrees, the temperature rise is 70 degrees. Make sure the tankless systems you install are powerful enough to provide this type of temperature rise.

Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection and Alarm Systems in Mechanical, Commercial and Residential settings. For more information on how to lower water-heating costs, to find out more about the advantages of tankless water heaters, or to view projects we’ve worked on, visit our website!

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