Quick Guide: Different Digital Heater Modes

An introduction to digital heaters

A. O. Smith (AOS) digital water heaters are the current top sellers by volume and one of the most frequently asked questions is how to use the different modes of digital heaters to customize usage and save energy.

Below is a brief summary of the differences between a regular AOS electric heater and AOS digital heater. Both heater tanks look identical but digital heaters come with a wired control panel, usually mounted close to heater tank.

The level of technology that goes into an AOS digital heater is completely different from that of an electric heater. This opens up many functions to offer users full control and customization of how the heater operates.

One of the functions of digital heaters is the ability to select from 3 modes, “standard”, “single” and “multiple”.

Standard mode: This is the most ideal setting for 70% of families in Singapore of 2 – 4 users.

Single mode: Recommended for single or very low usage users. Tank virtually splits into half, heating only half the maximum tank capacity. Users who do not always use the full tank can save more by reducing unnecessary heating.

Multiple mode: MAX technology, a patented AOS function is activated to virtually transform the tank into a larger heater. This mode can accommodate a sudden surge in usage for 5 – 6 users without running out of hot water.

The timer function

Enter the timer function! The timer makes our lives really easy, but used in conjunction with the modes, it may get a little confusing for first-time users. Most of the water heaters sold in the Singaporean retail market are electric heaters.

The typical electric storage user switches on the water heater about 15 min before entering the shower to ensure sufficient hot water is heated before the shower. The heater is usually switched off after use. Otherwise, it will continue to consume energy when water is reheated due to environmental heat loss.

The timer on the digital heater automates the process of the user having to switch the heater on and off by only heating water for peak periods. In this way, users do not need to pre-heat water before a shower or be worried about forgetting to switch off the heater after use.

How modes affect timers and vice versa

Building upon what we now know about modes and timers, this table will serve as a good guide for users who opt to use both the mode and timer function together.

The timer works across all 3 modes, “standard”, “single” and “multiple”. The difference lies in whether water will be heated when there is usage during an off-peak period.

Why heat water during off-peak in “single” and “multiple” mode?

In “single” and “multiple” mode, the MAX function goes on. The MAX function is like a ‘smart’ technology which detects and preempts usage during off-peak periods. It overrides the timer, heating water so that users do not run out of hot water.

The MAX technology comes in useful during periods like school holidays or weekends, when family members get up later than usual and take showers at irregular timings. When the holidays are over and there is no usage during off-peaks, the heater will revert to regular timer settings.

Digital heaters are a new generation of heaters which are fully automated so users do not have to manually tinker with the switch several times a day. They are highly reliable and widely used for energy saving solutions.



Amanda is an education specialist at AOS Bath. She enjoys building a trusted network by sharing knowledge. Making difficult concepts simple and engaging is rewarding, on both ends.