8 Key Factors to Consider When Choosing an Electric Water Heater

8 Key Factors to Consider When Choosing an Electric Water Heater

In our daily lives, we use water heaters almost every day, making it crucial to choose a safe and reliable model. Here are eight factors to consider when purchasing an electric water heater.

Key highlights of this article:

  • Hot Water Supply Speed
  • Hot Water Supply Volume
  • Hot Water Temperature
  • Water Pressure
  • Energy Label  / Power Consumption
  • Standby Power Consumption
  • Size
  • Limitations

1. Hot Water Supply Speed

Electric water heaters are available in three types: instant, rapid, and storage. Each type has different hot water supply speeds:

  • Instant Heaters: Provide hot water immediately without preheating.
  • Rapid Heaters: Heat water to 40°C within 5 minutes.
  • Storage Heaters: Take 15-25 minutes to provide hot water.

2. Hot Water Supply Volume

Instant heaters can continuously supply hot water, while central storage and shower storage heaters have capacities ranging from 12 to 38 liters, suitable for multiple outlets. Choose the capacity based on your bathing habits.

3. Hot Water Temperature

Most modern electric water heaters come with a thermostat for adjusting the temperature. However, the temperature range varies by brand. If you prefer hotter showers, look for models with high-temperature settings, which can go up to 85.5°C.

4. Water Pressure

Adequate water pressure is essential for electric water heaters to function properly. Insufficient water pressure can cause the heating element to burn out, posing a safety risk. Before purchasing, check your building's water pressure to ensure it meets the heater's requirements.

5. Energy Label / Power Consumption

Storage and rapid heaters typically require lower rated power, starting from 3,000 watts. In contrast, instant heaters need a higher rated power of 7,000 watts or more. Ensure your building can support three-phase power supply before opting for an instant heater.

6. Standby Power Consumption

The Electrical and Mechanical Services Department (EMSD) compares the annual standby power consumption of different electric water heater models. Lower standby power consumption indicates higher efficiency. A Grade 1 energy label signifies the most energy-efficient storage water heaters, making them the top choice for smart consumers.

7. Size

Instant heaters, lacking a storage tank, are compact and ideal for smaller bathrooms. Storage heaters range from 18 to 38 liters in capacity and can serve multiple outlets. Generally, the larger the storage capacity, the larger the heater.

8. Limitations

Users must regularly monitor the building's water supply status. When the water supply is interrupted, turn off the water heater to prevent dry burning. Once the water supply resumes, open the hot water tap for 1 minute to release air from the heater before restarting it.


When choosing a water heater, consider the type, shower duration, building water pressure, and budget.

After reading this Moorgenzine article, you should have a better understanding of how to choose an electric water heater. If you have any questions, feel free to contact Moorgen. Additionally, if you want to experience the benefits of smart home technology firsthand, visit Moorgen's showroom in North Point, Hong Kong, and discover the true smart home experience.

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