Flexible hot water

Water heaters are one of the most energy intensive appliances in our homes.

In the past, most have operated in the early hours of the morning. Now, we are exploring ways to shift a portion of water heating to the daytime to use cheap, abundant solar power.

This small change could help to support the switch to renewable energy. It also offers an extra tool to balance the network and provide safe, reliable power to all customers.

How does it work?

More than 140,000 of our customers connect hot water systems to a controlled load circuit. This allows us to remotely adjust the time when these devices operate.

The controlled load tariff was created to boost energy use in the early hours of the morning. Now, we can use it to help everybody share in the benefits of the energy transition.

Every day, unused solar power from homes and businesses is exported to the network. Victorians have installed so much solar that exports meet a large share of our energy needs.

Using this solar in real-time can help to balance the electricity network. This avoids the need to invest in poles, wires and other infrastructure. Ultimately, this helps to provide affordable energy to all customers.

Households with a controlled load tariff don’t need to do anything to make the change. We can use smart meters to remotely shift a portion of water heating to the middle of the day.

Can I sign up?

We started switching controlled load customers to daytime water heating in mid-2025.

Our initial trials showed positive signs. The change helped to balance the network, use more renewable energy and reduce emissions.

At the same time, we found some challenges. Demand for power is growing as customers switch to electric heating, cooking and transport. Moving water heating to the daytime can add to this demand and cause problems. This is a real issue in the cooler months, when solar output is lower and people rely on electric heating.

The popularity of rooftop solar is creating a surplus of electricity during the day. Heating water during these times helps us to manage demand across the network. Ultimately, this reduces the need for additional poles, wires and other network infrastructure.

Controlled load tariffs apply to some energy intensive household appliances. Typically, this includes water heaters, pool pumps, and underfloor heating.

A controlled load circuit allows these devices to be operated when energy is most abundant and affordable. This also helps to manage pressures on the network when energy usage is highest.

We can remotely activate devices on controlled load circuits using household smart meters.

No. Changes will not affect the supply of electricity to any customers.

Customers will continue to have access to hot water whenever they turn the tap.

If customers experience any issues, we will work with them to fix the problems as quickly as possible.

Our trial show that households don't use more electricity with daytime load shifting.

Electricity use from water heating can vary for a number of reasons. Often, this is due to changes to hot water use, weather and the performance of appliances.

Our trial showed that households did not pay more from daytime operation.

Bills can vary based on demand for hot water, weather and the performance of appliances.

Hot water load shifting aims to reduce energy costs in the long term. The changes reduce the need to invest in more poles, wires and other infrastructure.

Load is a term we use to describe the amount of energy being used on the electricity network. The higher the amount of electricity being used by customers, the higher the load.

Flexible loads refer to electricity use that can easily shift to different times of the day. Electricity networks use flexible loads to balance energy consumption during off-peak periods. Historically, this has been between the hours of 10pm and 7am.

Flexible loads can reduce energy bills, increase use of renewable energy, and balance the network. This helps to keep power reliable and affordable for customers.

Contact your electricity retailer directly.