How can you design energy-efficient water heating in buildings?

2 Size of water heaters

The size of the water heater determines how much hot water it can provide at a given time and how much energy it consumes. If the water heater is too small, it may not meet the peak demand and cause discomfort and frustration. If the water heater is too large, it may waste energy and money by heating more water than needed. To size the water heater correctly, you should estimate the peak demand of hot water in your building, based on the number and type of fixtures, the flow rate and temperature of water, and the occupancy and schedule of users. You should also factor in the recovery rate and the first-hour rating of the water heater, which indicate how fast it can heat water and how much hot water it can deliver in the first hour of operation.

3 Location of water heaters

The location of the water heater affects the efficiency and convenience of the water heating system. Ideally, the water heater should be located as close as possible to the point of use, to minimize the heat loss and the waiting time for hot water. However, this may not be feasible or practical in some cases, especially for large or multi-story buildings. In such cases, you may need to install multiple or decentralized water heaters, or use a recirculation system that circulates hot water in a loop and reduces the waste of water and energy. You should also ensure that the water heater is installed in a well-ventilated and insulated space, to prevent overheating and heat loss.

4 Distribution and insulation of pipes

The distribution and insulation of pipes play an important role in the energy efficiency and performance of the water heating system. The longer and more complex the pipe network, the more heat loss and pressure drop occur, resulting in lower water temperature and flow rate at the point of use. To optimize the distribution of pipes, you should use the shortest and simplest route possible, avoid unnecessary bends and fittings, and balance the pressure and flow in the system. To reduce the heat loss of pipes, you should use proper insulation materials and techniques, such as wrapping pipes with fiberglass or foam, sealing joints and gaps, and covering exposed pipes with jackets or sleeves.

6 Smart controls

Smart controls are devices or systems that monitor and regulate the operation and performance of the water heating system, using sensors, timers, thermostats, or remote controls. Smart controls can help you save energy and money by adjusting the water temperature and flow rate according to the demand and usage patterns, switching off the water heater when not needed, detecting and preventing leaks and malfunctions, and providing feedback and alerts. Some examples of smart controls are programmable thermostats that allow you to set different temperature settings for different times of the day or week, occupancy sensors that turn on the water heater only when someone is present, and smart meters that track and display the energy consumption and cost of the water heating system.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?