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Best Instant Hot Water System

If you are looking to find the best instant hot water system for your home, it can be tough to know where to start. After all, the Australian tankless hot water system market is filled with dozens of high-quality products manufactured all over the world, with a wide array of prices, technologies, and warranties available. 

To save you time and energy on the hunt for your next home appliance upgrade, we’ve rounded up the best instant hot water systems in Australia for homes of all shapes and sizes.  

So what are the best instant hot water system for Australians?

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Our Pick for Instant Hot Water:

While it is difficult to definitively say that one tankless heater is going to be the best choice for everyone, we can certainly say that the Rinnai Infinity 26 may be as close as it gets. For the best overall instant hot water system available nationwide, Australian homeowners should strongly consider the Rinnai Infinity 26 as a long-lasting, money-saving device.  

Rinnai Infinity 26 – Continuous Flow Hot Water System

Why the Rinnai Infinity 26 is our number one choice:

  • 6-star energy efficiency rating
  • 25 year extended heat exchanger warranty 
  • Precise water temperatures
  • Perfect for 1-2 bedroom homes

Designed with energy efficiency in mind, the Japanese-manufactured Rinnai Infinity 26 is a gas-powered tankless water heater ideal for small Australian households. Available in most major cities through a variety of retailers, this 6-star hot water system has the longest heat exchanger warranty of its kind in the country.

We love the Rinnai Infinity 26 because it allows homeowners to be as green as possible with a gas-powered system that does not sacrifice convenience or power. With instant hot water available at all times, the Rinnai Infinity 26 can be powered by LPG or natural gas and is compatible with low-flow shower and bathroom systems.

Packaged together in a confined space-saving model, the Rinnai Infinity 26 offers precise control of a home’s hot water with minimal invasion and great after-sales support. While it is certainly not the cheapest option on the market, the Rinnai Infinity’s energy efficiency and warranty can save building owners a significant amount of money on water heating costs over time.   

Other Great Instant Hot Water Systems in Australia

Of course, the Rinnai Infinity 26 instant water heater is not the end-all, be-all when it comes to reliable tankless hot water systems available in Australia. If you’d like to evaluate a few other instant hot water heaters, here are a handful of more great choices for homeowners Down Under.  

Stiebel Eltron DHE AU Instant Water Heater 

What to love about the Stiebel Eltron DHE AU:

  • German engineered, fully electric system  
  • Precise hot water temperature up to 60°C
  • Available nationwide at various retail rates
  • 5-year parts and labour warranty

For Australian homeowners looking to purchase a high-quality instant hot water system without handing over their life savings, the Stiebel Eltron DHE AU is a great product found in most retail environments. Built to last long with a 5-year part and labour warranty, the physical installation of a DHE AU is covered for years beyond most domestic products with 1, 2, and 3-year guarantees.  

Available nationwide through over a dozen well-known plumbing part providers, the German-engineered DHE AU, takes international technology and perfectly adapts it for Australian properties with 3 phase power. To best fit the demands of various home and family sizes, the DHE AU is available in 18 KW and 27 KW models, both of which are compact and have a nominal capacity of 0.4L.

Most importantly, as a fully electric system, the Stiebel Eltron DHE is a great choice for people seeking an alternative to a gas-powered heater. Approved by the Energy Efficiency Council and the Green Building Council Australia, the Stiebel Eltron DHE AU instant water heater is a smart choice for your wallet, home, and carbon footprint. 

Dux Always Hot Condensing Continuous Flow 21L

Reasons to purchase the Dux Always Hot Continuous Flow:

  • Energy-efficiency rating of 6.7 stars
  • 21 liter & 26 liter/minute models available 
  • 12-year warranty on heat exchanger
  • Full line of optional accessories for smart home upgrades

Assembled here in Australia, the Dux Always Hot Condensing Continuous Flow 21L Water Heater is a great product manufactured for unique domestic conditions and performance. With a 6.7-star energy efficiency rating, the DUX Always Hot is among the best-performing systems on the market, capable of saving homeowners a tremendous amount of gas and water heating costs over time.

Available in 21L and 26L models, each unit is densely packed into a durable case and is easily installed on an exterior wall. The stainless steel heat exchanger is warrantied for 12 full years, and parts and labour are guaranteed for three, making it a wise investment for long-term access to reliable, instantaneous hot water.

Based on Japanese technology, the Dux Always Hot Continuous Flow includes electronic ignition, which completely eliminates the need for a standby pilot light. With instant hot water at the push of the tap, both the 21L and 26L Dux Always Hot systems work great for mid-size and large homes with 2 to 3 water outlets. 

Rheem Metro 26L Gas Continuous Flow Water Heater 

Highlights of the Rheem Metro 26L:

  • 50°C limited temperature and 60°C options available 
  • 26L for homes up to 5 people 
  • 10-year warranty on heat exchanger
  • Propane or natural gas-powered systems for sale

As an American company based in NSW, Rheem Australia offers international brand recognition with their high-quality Metro 26L Gas Continuous Flow Water Heater. Designed for homes of up to 5 people, the Rheem Metro 26L Gas Continuous Flow is a fully capable device that can typically be installed for fewer costs than most other top-of-the-line products.

Including 50°C limited temperature and 60°C model options, the Rheem Metro is a safe choice for both CPG and natural gas hot water use. With a 10-year heat exchange and 3-year labuor warranty, the Rheem Metro 26 L is among the highest quality products available today with the company’s Q Factor guaranteeing rapid hot water, every single time the tap is turned. 

Last but not least, the Rheem Metro 26L gas continuous flow water heater has a 6-star energy rating, with new models constantly becoming more efficient. Tied together with a remote-powered option for complete temperature control, the Rheem Metro 26 L is well worth considering as a smart upgrade for most Australian homes.  

Thermann 6 Star Continuous Flow Hot Water System

What to know about the Thermann 6-Star Continuous Flow Hot Water System:

  • 16L, 20L, and 26L models for homes of all sizes
  • Propane and natural gas options are available
  • 12-year heat exchanger warranty
  • Universal controllers and other optional upgrades 

Finally, the Thermann 6-Star Continuous Flow water heater is a versatile product from a 100% Australian-owned company. If you’d like to keep your money Down Under as much as possible, the Thermann 6-Star Continuous Flow system is a great local choice for homes of all sizes, with 16L, 20L, and 26L models available. 

In addition to the different flow capacities, Thermann offers their tankless hot water systems with natural gas, LPG, and 50/60 degree models available. Backed by a 12-year heat exchange warranty, a 3-year guarantee on parts and labour, and one of the fastest-growing domestic hot water brand names, homeowners can rest assured that the Thermann 6-Star is a solid investment in energy-saving performance.

With Japanese technology and an Australian-owned workforce, the Thermann 6-star continuous flow gas water heater is watermarked and AGA approved for safe operation. Now with universal controls available, it has never been easier to ensure you have access to precisely operated hot water in your home with the Thermann 6-star continuous flow hot water system.   

How to Choose Your Instant Hot Water System 

Now that we’ve showcased some of the best instant hot water systems on the Australian market, here are the things to keep in mind when finding the ideal appliance for your property. 


First and foremost, the term “instant hot water system” actually serves as a nickname for a few different kinds of products. In some cases, if you think you’ve found a great deal on a full-home continuous hot water heater, it is crucial that you must verify that you are purchasing the right kind of product for your property.  

From electric tea kettles to small water heaters designed to meet the demands of campers and RVs, there are plenty of “instant hot water systems” on the market that cannot power a full home. As such, it is always advisable to double-check your shopping cart before committing to the wrong kind of appliance.  

Size and Shape

Although tankless water heaters are designed to save space, they are still capable of occupying a significant portion of the limited space on the property of a small apartment, home, or condo. And while you may have the perfect spot in the backyard for the new system already picked out, your installer may have bad news if the location will not work logistically with the home’s plumbing. 

Thankfully, unlike traditional water heaters, tankless systems only have a small component that is used to heat a home’s water and exterior installation considerations are rarely an issue for most. When wall space is limited, if possible, we recommend an onsite consultation with a plumber before you make a purchase.  

Power Source

In today’s appliance market, Australia’s instant commercial hot water systems are typically powered by gas (natural or Liquefied Petroleum), but more and more devices are being introduced that solely run on electricity. While the cost-benefit analysis largely depends on local availability and utility prices, certain homes may be able to utilize gas or electricity as a cheaper long-term option. 

With that said, both electric and gas powered tankless hot water systems continue to become more energy-efficient as new models continue to improve. However, when paired with a renewable energy source such as PV solar, electric instant hot water systems can be cheaper and more environmentally friendly to run over long periods of time.


Speaking of costs, it is simply impossible to ignore the sticker price of a tankless water heater as it relates to your purchasing decision. Of course, when evaluating your choices, it is very important to consider all of the costs associated with a tankless water system, which includes parts, installation, transportation, and occasionally other hidden fees.

When speaking with potential plumbers about your new system, be sure to ask what metrics are included in the price of the unit. In some cases, certain companies will be able to offer free installation and/or ongoing maintenance services to save you money upfront, close a deal, and move forward. 

Energy Efficiency 

To save on costs over time, energy efficiency is an aspect of tankless water heaters that should certainly not be ignored. In Australia’s cities that are lucky enough to experience all four seasons, energy efficiency is critical to keeping costs low during cold winters, when warm showers and hot water appliances need to use more energy to meet building demands. 

While shopping around for the right hot water heater, most companies will claim that their systems are efficient in some way or another, but smart customers can look at energy input and output, flow rates, and other measurements to determine approximate long-term running costs. Be sure to look for energy efficiency labels, as that remains objectively managed.  


With the big picture in mind, there are very few things that are as important to consider when purchasing an instant hot water system as the included warranties. Often protected separately at the product, parts, and labour levels, your full system warranty will depend on both the manufacturer and installer of your tankless heating system. 

By and large, a long warranty period not only protects consumers against future maintenance costs but also highlights products and manufacturers that believe in the quality of their systems. Although a budget may prevent you from buying a top-of-the-line model, a short warranty period will only cause headaches in the future if you decide to purchase a cheap system.  

Rebates and Incentives

Finally, energy efficient models of instant hot water systems (and many other home appliances) may be eligible for rebates and incentives to help drive down the initial costs of installation. 

All over the country, local and national rebates and incentives are available at different rewards levels and may be able to be paired with a solar energy system, as electric tankless heaters are more likely to be eligible for various hot water rebates in Australia.

Instant Hot Water System FAQ

Finally, let’s take a look at some of the most frequently asked questions related to instant hot water systems to paint a full picture of the products themselves and leave no stone unturned.  

What is an instant hot water system?

Although technically not instantaneous, “instant hot water systems” are a nickname for the more accurate label of “tankless” or “continuous” hot water heating appliances. As the technology advances and systems continue to work quickly and efficiently, on-the-spot heating for an entire home’s hot water supply is becoming faster and faster, though it can never truly become “instant” for a continuous residential water supply. 

What is the difference between a tankless and an instant hot water heater?

There are no differences between tankless and instant hot water heaters, as the terms are generally used interchangeably. When purchasing any sort of “instant hot water system,” it is very important to ensure that you are evaluating products based on the water supply necessary to fulfill the needs of a home, business, campervan, or property. 

Are instant hot water heaters efficient?

Yes, instant or tankless hot water heaters are manufactured to be as energy-efficient as possible. By heating water only when it is actively in use, households that are not consuming large amounts of water can save on monthly energy consumption with continuous and point-of-use systems. If you aren’t sure a continuous hot water system is for you, solar hot water heaters and hot water heat pump systems are also extremely efficient, both offering some compelling benefits (as well as drawbacks), and would be worth investigating.

What are the advantages of a tankless water heater?

Without a massive tank, continuous or tankless water heaters do not require the space necessary to accommodate traditional systems. They are typically very energy efficient, do not require a significant amount of ongoing maintenance, and can save home and building owners money on both short and long-term energy costs.  

What are the disadvantages of a tankless water heater?

While some tankless systems are very efficient when it comes to heating a home’s water, the technology is overall slower to deliver hot water than traditional systems with hot water storage tanks. With an electric or utility gas-powered system, building owners will also not be able to access new hot water during a blackout or power outage when public resources are limited or unavailable. 

How many years does a tankless water heater last?

Although warranty periods typically last between 5 and 10 years, there are plenty of tankless hot water systems that can work efficiently for 15 to 20 years and more. When evaluating various products, advanced tankless systems can usually deliver a slightly longer lifespan than traditional hot water tanks at the same price points. 

What maintenance is required on a tankless water heater?

Over time, a tankless water heater requires a relatively small amount of maintenance with recommended inspections every 2 years or so. Routine instant hot water system check-ups typically include component cleaning, flushing, and preventive maintenance services. Intervals between maintenance should continue to shorten a system’s lifespan, and inefficient systems should be replaced to save money and energy.


At the end of the day, there are a lot of reasons to go tankless, and we hope that this guide has helped you better understand the world of instant hot water systems. With an ongoing commitment to economically and environmentally friendly products, Envio Friendly is proud to be Australia’s go-to resource for hot water systems and other eco-friendly home upgrades.