Hot water

If you need a new hot water system, or if you are looking to upgrade one, then it’s important to be as energy-efficient as possible. Hot water systems can often be responsible for 40% of a household’s energy usage and they can last for around 10 years, so choose carefully.

If your system is more than 7 years old, it is important to start preparing today to upgrade to an efficient system, so that you don’t find yourself needing to replace the system in a rush down the track.

There are many different types of hot water systems, all with different running costs.

Source: Sustainability Victoria

What is the most efficient type of hot water service?

The graph below shows the annual running costs for the most common types of hot water systems.

Source: Energy Consult

As you can see, both heat pumps and solar hot water systems are very efficient with very low running costs. However, we recommend households to install a heat pump over solar hot water for a number of reasons:

  • Many households are moving away from using natural gas as it is a fossil fuel with associated greenhouse gas emissions
  • The cost of gas continues to rise each year
  • Solar hot water systems use up roof space exclusively for hot water. Instead, this space could be used to install solar panels, which can provide power to other appliances as well as hot water
  • If hot water is your last gas appliance, you could be financially better off replacing it with an efficient electric system and disconnecting from mains gas to save on the daily supply charge. This could save you a further $200-$300 per year

What is a heat pump?

Traditional electric water heaters use electricity to heat water directly through an element, whereas, a heat pump uses electricity to operate a pump that circulates a refrigerant around the system. The pump uses far less electricity than the element. A refrigerant then picks up ambient heat from the air and transfers it to the water. It’s the same principle as a reverse cycle air-conditioner; it just heats water instead of air. In this way, heat pumps are able to use far less electricity than traditional electric hot water systems. That means they cost less to run and create less greenhouse gas emissions. In fact, the running costs of heat pumps can be up to 45-65% lower, depending on if your existing system is gas or electric!

Heat pump technology has been around for more than 100 years, so it is well and truly proven. They have been popularly in use for decades in the USA and many parts of Europe, particularly Italy and Spain.  In Australia, thanks to generous government rebates and rising energy prices, more and more households have been making the switch to heat pump hot water systems.

How much do they cost?

On average, you can expect to pay between $2,000-$4,000 for a heat pump.

Are there rebates available for heat pumps?

Yes! Hot water heat pumps attract rebates from the Federal Government as part of the Small Scale Renewable Energy Scheme.

Who is a heat pump best suited for?

  • Anyone with an existing gas or electric storage hot water system more than 7 years old
  • Homes with up to 4 residents
  • Anyone with a solar power system. Heat pumps only require a small amount of power so they can be very easily powered by your solar – even with smaller power systems
  • Households with hot water as the only gas appliance. Switching to a heat pump can allow you to disconnect from mains gas and save an additional $200-$300 per year in supply charges

Aren’t heat pumps noisy?

The way that a heat pump works is similar to an air-conditioner running ‘reverse-cycle’. The main difference is that a heat pump heats water rather than air. You have probably come across air-conditioners and have heard the ‘fan-coil’ unit whirring away on a hot day. Heat pump systems are similar and care should be taken when choosing where to locate a heat pump, for example, away from bedrooms or places where the noise might disturb others.

How will it work with my solar power system?

Heat pumps are very easily integrated with existing solar power systems. Most come with a built in timer which allow the system to be operated during the day which means you can use free power from the sun to power your system!

Many heat pumps come with a built-in timer which means you can very easily set them to run during the day, allowing you to power the heat pump using free electricity from the sun! Most heat pumps only require a small amount of power to run which means even small solar power installations can generate enough power during sunny days to run them. Check out our ‘Use Your Power’ activity for more advice on how to use your solar power in your home and what you can do to maximise the benefits of having solar.

Do heat pumps work in cold weather?

It is true that in areas of frequent frost, the system takes a little longer to heat up the hot water, however, most heat pumps have been designed to operate in cold conditions. Check with the manufacturer to confirm under which conditions the system can operate.

Can I set up the heat pump on a controlled load tariff?

Depending on your location it may be possible to set up the heat pump to operate on a controlled load electric tariffs.  If available, this means you can operate the heat pump on a much lower electricity tariff leading to even more dollar savings! Please check with your electricity retailer to see if this is possible in your area.

Use less hot water

No matter the system you have, reducing your hot water usage can have a big impact on your overall energy usage. Here are some of our favourite tips!

  • Install water efficient showerheads to reduce hot & cold water usage. Showers typically use the vast majority of your hot water, and water heating often constitutes around 40% of your energy bills. This makes installing an efficient showerhead a good investment for both reducing your water and energy bills.

  • Use cold water when washing your hands, shaving or cleaning your teeth
  • Take shorter showers, ideally 4 minutes or less. Use a shower timer as a reminder.
  • Fix leaking taps and appliances.
  • Wash laundry in cold water. This can save you around $100 per year.
  • Make sure the thermostat of your hot water system isn’t too high. For a storage hot water system set it to 60°C and for an instantaneous hot water system set it to 50°C. Too high a temperature means that energy is used unnecessarily.
  • Maintain your hot water system and have it serviced according to manufacturer’s instructions. This will extend the life of your hot water system.
  • Install tap aerators or flow controllers to reduce water flow