Hot Water Systems Compared


Compare hot water systems from Rinnai, AquaMax, Rheem, Bosch and Dux. Systems are reviewed on their effectiveness, reliability, quietness, ease of use, after sales service/warranty, value for money & overall customer satisfaction in 2017.

See our Ratings Methodology.

2017 award for hot water systems

Most Satisfied Customers | Rinnai

In the inaugural year of our customer ratings for hot water systems, Rinnai leads the way from AquaMax, Rheem, Bosch and Dux, scoring five-star reviews from users on effectiveness, reliability, quietness, ease of use, after sales service/warranty, value for money, and overall customer satisfaction in 2017.

Rinnai the winner in hot water system ratings

Finding the best hot water system for your home is no easy task. You first need to understand what different types of hot water systems are available, get to grips with their ongoing running costs, and find a product that best meets your needs and budget. To help you on the road to a reliable and cost-effective hot water system, Canstar Blue has produced this guide. In it we review the different types of systems available in Australia, compare ongoing running costs, and find out which brands are rated highest on factors such as effectiveness, reliability, value for money and overall customer satisfaction.

To produce our customer satisfaction ratings for 2017, we’ve surveyed hundreds of households right across Australia, finding out what type of system they use, how much they paid for it, and how they rate their brand of choice across several key variables. Five leading brands have featured in the final results, but only Rinnai scored a five-star review on overall customer satisfaction in 2017. In fact, Rinnai achieved five stars across all research categories. It was four stars overall for AquaMax and Rheem, while Bosch and Dux both rated three stars.

Now we know which brands are rated highest, let’s go into detail about the types of hot water systems available in Australia, what they are likely to cost you upfront, and how much they are likely to add to your ongoing energy bills. We’ll then provide an overview of the five brands that have been reviewed to help you make a decision on which will be best for your circumstances.

Types of hot water systems

The humble hot water system might seem like an unlikely culprit for large energy bills, but did you know that the cost of heating water can make up 30% of an average Australian household’s total electricity bill? Your hot water system could be costing you big time – depending on the type you have – so we’ve compared electric, gas, solar and heat pump hot water systems to help you find the best and most cost-effective water heating solution for your home.

Hot water systems come in two designs – ‘storage’ and ‘continuous flow’ (also known as instantaneous). A storage hot water system heats and maintains warm water in a tank until it is ready to use. This provides instant hot water, but is limited by storage capacity. Continuous hot water systems – on the other hand – rapidly heat up an unlimited amount of water when you need it. While it does take a few moments to heat up, an instantaneous system won’t waste energy by keeping water warm when no one is using it.

Electric Water Heaters

How they work

Electric storage hot water systems heat water using an electric-powered element which sits at the base of the water tank. Continuous systems work in a similar way, but instead the element is coiled around the pipes to rapidly heat the water inside.


Electric hot water systems have quite low up-front costs and are a reliable way to keep your water warm. Some electric hot water systems can also be programed to do the majority of its heating during off-peak periods to help minimise your energy bill.


Electrical hot water systems are almost always the most expensive long-term hot water solution. They also have high greenhouse gas emissions and are generally discouraged.

  • Cost: $200 to $2,000

Gas Water Heaters

How they work

Storage systems use a gas burner to continuously heat and maintain water in a tank at 60°C. Continuous flow systems also use a burner which ignites only when the water is needed.


Gas hot water systems produce less greenhouse gas emissions than electric water systems. Additionally, depending on your location, gas systems are usually considered to have lower usage rates compared to electricity, making them the most cost-effective option long term.


Gas hot water systems are only really viable if you’re connected to mains gas, as using LPG bottles is more expensive and creates the risk of running out of hot water. Gas hot water systems must be located outside, or have an exhaust vent if they are located inside.

  • Cost: $800 to $1,900

Solar Water Heaters

How they work

Solar hot water systems are storage units which generate heat from the sun using panels installed on the roof of the property. This heat is used to warm and maintain the water in your tank. When there is insufficient solar generation, systems can be boosted to a temperature of 60°C by either electric or gas boosters.


Solar hot water systems are able to reduce your hot water system’s energy consumption by up to 90%. Being that hot water systems are notoriously energy hungry, this can mean significant savings on your power bills. Solar hot water systems are also the most environmentally friendly option. Accredited solar systems are also eligible for STC rebates from the federal government through the Clean Energy Regulator as well as other state-specific rebate schemes.


Solar hot water systems have the highest up-front costs – anywhere from $2,000 to $7,000 after rebates depending on the system size, and excluding installation costs. Some solar hot water systems may also be unreliable on overcast days, though most models will kick-over to gas or electric back-up heating if the water isn’t hot enough.

  • Cost: $2,000 to $8,000

Heat Pump Water Heaters

How they work

Heat pumps have a fan that draws warm air into the system, which is transferred to the water storage tank. It’s essentially a reverse fridge. Rather than pumping out hot air to keep your fridge cool, it pumps hot air in to heat the water up.


Heat pumps are one of the most energy efficient hot water solutions. While they need electricity to run, they are roughly three times more efficient than traditional electric water heaters.


Heat pumps are only suitable in warm environments. While some heat pumps do come with boosters, if the climate isn’t suitable, there is little benefit in spending the extra money on a heat pump. They are also considered unreliable and servicing costs are generally expensive.

  • Cost: $2,500 to $4,000

Hot water system running costs

The below table, courtesy of the NSW Government’s Smarter Choice Initiative, shows the estimated running costs of different hot water systems. As mentioned, gas boosted solar storage hot water systems are the cheapest over time with an annual cost of only $183 for a medium-sized household. LPG gas and continuous electric systems prove the most expensive, costing $901 and $1,111 respectively per annum.

Household size & water usage Energy source Type Annual cost*
Small 1-2 people

77 litres per day

Gas Continuous flow $215
LPG $529
Electricity Cont. – DR^ $610
Off peak $357
Solar Gas boosted $98
Electric off peak boost $125
Medium 3-5 people

156 litres per day

Gas Continuous flow $360
LPG $901
Electricity Cont. – DR^ $1,111
Off peak $563
Solar Gas boosted $183
Electric off peak boost $197
Large 6-8 people

231 litres per day

Gas Continuous flow $497
LPG $1,254
Electricity Cont. – DR^ $1,589
Off peak $759
Solar Gas boosted $261
Electric off peak boost $266

* Approximate cost based on 32c/kWh and 2c/MJ

^ Continuous – Day Rate

What’s the best type of hot water system?

If you’re connected to mains gas and your home receives at least moderate amounts of sunlight, the most ideal system for you could be a solar storage hot water system with gas boosters. If your home doesn’t get much sunlight, the next best thing in terms of running costs would likely be a continuous flow gas system. However, there is no ‘one size fits all’ solution when it comes to cutting your energy bill. It could be said that you should avoid electric hot water systems if possible, particularly continuous flow models, as they have high emissions and are often considered to be the most expensive option.

Let’s now get an overview of the five brands in our 2017 review, with details about the types of hot water systems they offer.


When you look at the massive range of Rinnai hot water systems, it’s not hard to see why this brand took the top spot in this year’s ratings. Rinnai produces two lines of continuous gas water heater: Infinity and Hotflo. It also produces a range of domestic and commercial solar, electric, gas and heat pump storage systems, along with gas boosters and other accessories to manage hot water usage, provide added security, or improve the aesthetics of your system. Prices for a Rinnai storage system start from around $500, while continuous flow systems will usually set you back at least $1,000. If you’re considering a Rinnai solar hot water system however, expect to pay at least $2,000.


Aquamax produces gas storage, electric storage and gas continuous flow hot water systems. It also has a ‘premium’ range of stainless steel storage systems which it says are lighter, more energy efficient and easier to maintain than regular models. Aquamax prices start from as low as $400 for its smallest electric storage system. The continuous flow systems are considerably more expensive, however, priced around the $1,200 mark.


Rheem produces all kinds of water heaters, including electric, gas, heat pump and solar storage, as well as gas continuous flow systems. Rheem hot water systems are deliberately designed to cater for a variety of needs. It has steel systems for added durability, compact systems for those tight on space, plus extra-large models and plenty more. A small electric Rheem storage system will set you back at least $500, with larger models costing up to about $1,500. Continuous flow systems start around $800. Solar hot water with Rheem can cost anywhere between $1,200 and $3,000.


While Bosch does produce electric and heat pump storage systems, what actually sets Bosch apart from other brands is its range of gas continuous hot water systems, with its patented ‘Optiflow’ technology. Bosch says its Optiflow hot water systems provide more responsive hot water and include Bluetooth connectivity so users can track usage data and adjust the water temperature from their phone. Bosch Optiflow hot water systems start at a reasonable price of about $800.


Dux produces a huge range of hot water systems, including heat pump, electric, gas and solar boosted storage systems, as well as gas continuous flow water heaters. Dux storage systems come in a plethora of sizes between 25L and 400L, so there should be something suitable for your home. If continuous flow is more your style, you might be interested to know that DUX systems have a 6.7 star energy efficiency rating – higher than most similar models on the market. Small Dux electric storage systems start at around $350, while its continuous flow systems will set you back at least $800. Expect solar water heating to cost a couple thousand, depending on the size of the system.

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How to save on hot water heating

Hot water is a necessity, meaning it’s somewhat of an inevitable cost. That said, there are ways to minimise your hot water system’s impact on the energy bill.

One of the easiest ways households with electric storage systems can save on hot water is with a controlled load tariff. Sometimes referred to as a ‘dedicated circuit’ or two-rate tariff, it’s an arrangement where the hot water system is metered separately to the rest of the house and charged a lower usage rate on electricity. Electricity is only supplied to the hot water system during off-peak usage hours, usually from 11pm to 7am depending on the electricity network. During these hours, the hot water system will heat the water and store it for use later on.

Most hot water systems are installed with a dedicated meter, meaning that retailers will often put you on a controlled load tariff by default. If, for whatever reason, you don’t have a controlled load tariff, Canstar Blue calculates that you could stand to save big by making the switch.

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Frequently asked questions

Canstar Blue surveyed 3,000 Australian adults across a range of categories to measure and track customer satisfaction. Data was collected using Qualtrics’ online sample aggregation from ISO accredited panels. The outcomes reported are the results from customers within the survey group who have purchased a new hot water heater in the last 5 years – in this case, 582 people.

Brands must have received at least 30 responses to be included. Results are comparative and it should be noted that brands receiving three stars have still achieved a satisfaction measure of at least six out of 10. Not all brands available in the market have been compared in this survey. The ratings table is first sorted by star ratings and then alphabetically. A rated brand may receive a ‘N/A’ (Not Applicable) rating if it does not receive the minimum number of responses for that criteria.

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