How Do Instant Hot Water Systems Work?

Instantaneous hot water systems revolutionise the way we access hot water in our homes. These innovative appliances, also known as tankless water heaters, provide hot water on demand without the need for a storage tank. An instant hot water system heats water as it flows through the unit, using either gas or electricity to rapidly warm the water to the desired temperature.

These systems offer several advantages over traditional storage tank water heaters. They’re more compact, taking up less space in your home, and can be more energy-efficient as they only heat water when it’s needed. This means you’re not wasting energy keeping a large tank of water hot all day.

The technology behind instant hot water systems is straightforward yet effective. When you turn on a hot water tap, cold water flows into the unit and passes through a heat exchanger. This component rapidly heats the water using either a gas burner or electric heating elements. The result is a continuous supply of hot water, perfect for busy households with high hot water demands.

how does an instant hot water system work

What is an Instant Hot Water System?

An instant hot water system, also known as a tankless water heater, is a modern appliance designed to provide hot water on demand. Unlike traditional storage tank systems, it doesn’t keep a large volume of pre-heated water.

These systems heat water as it flows through the unit, delivering a continuous flow of hot water whenever needed. They’re compact and efficient, making them increasingly popular in Australian homes.

Instant hot water systems come in two main types:

  1. Instant gas hot water systems
  2. Instant electric hot water systems

Gas systems typically offer higher flow rates, making them suitable for larger households. Electric models are often more compact and easier to install in smaller spaces.

Instantaneous hot water systems are energy-efficient, as they only heat water when required. This can lead to lower energy costs and bills compared to traditional storage systems.

Key benefits of instant hot water systems include:

  • Energy and cost savings
  • Space-saving design
  • Continuous hot water supply


It’s important to note that while these systems offer many advantages, they may not be suitable for every household. Factors such as water usage patterns and existing plumbing infrastructure should be considered when choosing a hot water system.

what is an instant hot water system

How Do Instant Hot Water Systems Heat Your Water?

Instant hot water systems utilise advanced heating technology to provide hot water on demand. These systems employ efficient heat transfer methods and precise flow control to deliver a continuous stream of heated water.

Core Components

The heart of an instantaneous hot water system is its heat exchanger. This crucial component rapidly transfers heat from the energy source to the flowing water. In gas-powered units, a burner heats the exchanger, while electric models use heating elements.

A flow sensor detects when hot water is needed, triggering the heating process. The system also incorporates temperature sensors and a control unit to maintain the desired water temperature.

Safety features like pressure relief valves and anti-scald mechanisms are essential components that protect users and the system itself.

Operating Principle

When a hot water tap is turned on, cold water enters the instant hot water system. The flow sensor activates the heating mechanism – either a gas burner or electric element. As water passes through the heat exchanger, it’s rapidly heated to the set temperature.

Gas systems use a powerful burner to heat the exchanger, while electric models employ high-wattage elements. The control unit modulates the energy input based on water flow and temperature requirements, ensuring consistent output.

This on-demand heating approach eliminates standby energy losses associated with storage tanks, making instantaneous systems highly efficient for many households.

Types of Instant Hot Water Systems

Instant hot water systems come in two main varieties: gas and electric. Each type of instantaneous hot water system has its own unique features and benefits for providing on-demand hot water to Australian homes.

Gas Systems

Gas instant hot water systems utilise a powerful gas burner to heat water rapidly as it flows through the unit. These systems can run on natural gas or LPG, making them versatile for different home setups.

Gas systems typically offer higher flow rates, allowing multiple taps to be used simultaneously without loss of water pressure. They’re also more energy-efficient than their electric counterparts, especially for larger households.

Installation requires proper gas connections and ventilation. While initial costs may be higher, gas systems often have lower running costs over time. They’re ideal for homes with existing gas connections or those in areas with reliable gas supply.

Electric Systems

Electric instant hot water systems use heating elements to warm water on demand. They’re compact and can be installed close to point-of-use, reducing heat loss through pipes.

These units are generally more affordable upfront and easier to install than gas systems. They’re particularly suitable for small households or single-outlet applications like kitchen sinks or bathroom basins.

Electric systems have lower flow rates compared to gas models. This means they may struggle to supply hot water to multiple hot water outlets simultaneously. They can also be more expensive to run, especially during peak electricity tariff periods.

For environmentally conscious homeowners, electric systems can be paired with solar panels to reduce energy costs and carbon footprint.

why get an instant hot water system

Why Get an Instant Hot Water System?

Instant hot water systems offer significant advantages for Australian households. These units provide energy efficiency, space-saving benefits, and a continuous supply of hot water to meet daily needs.

Energy and Cost Savings

Instant hot water systems are highly energy-efficient, as they only heat water when needed. This on-demand approach eliminates standby energy losses associated with traditional storage tanks. By heating water instantly, these systems can reduce energy consumption by up to 30%.

The energy savings translate directly to lower utility bills. Over time, the reduced operating costs can offset the initial higher purchase price of an instant system. Many Australian households find that their energy bills decrease noticeably after switching to an instant hot water system.

Additionally, instant systems are often eligible for government rebates and incentives, further enhancing their cost-effectiveness.

Space Conservation

One of the most appealing aspects of instant hot water systems is their compact size. Unlike bulky storage tanks, these units are typically wall-mounted and take up minimal space.

This space-saving feature is particularly valuable for smaller homes, apartments, or properties with limited storage areas. The compact design allows for flexible installation options, such as in cupboards or outdoor areas.

By freeing up valuable floor space, homeowners can utilise the area for other purposes or simply enjoy a less cluttered living environment.

Continuous Water Supply

Instant hot water systems provide an endless supply of hot water, eliminating the risk of running out during peak usage times. This feature is especially beneficial for larger households or families with high hot water demands.

Unlike storage tanks that can be depleted, instant systems heat water on-demand, ensuring a constant flow of hot water for multiple simultaneous uses. This means no more waiting for the tank to refill and reheat between showers or during busy mornings.

The continuous flow hot water supply also allows for more efficient use of hot water, as there’s no need to overfill baths or run taps unnecessarily to avoid using up the stored hot water.

Installation and Maintenance

Proper installation and regular maintenance are crucial for the efficient operation and longevity of instant hot water systems. These factors ensure optimal performance, safety, and cost-effectiveness over time.

Professional Installation

Installing an instantaneous hot water system requires expert knowledge and skills. A licensed plumber should handle the installation to ensure compliance with local regulations and safety standards. The process involves:

  • Selecting an appropriate location
  • Connecting gas or electrical supply
  • Installing water inlet and outlet pipes
  • Setting up venting systems (for gas units)


Installation costs vary depending on the system type and complexity. In Australia, prices typically range from $1,500 to $3,000, including labour and materials.

Professional installation guarantees proper functioning and maximises energy efficiency. It also helps prevent potential safety hazards associated with improper setup.

Routine Maintenance

Regular maintenance is essential for keeping instant hot water systems in top condition. Key maintenance tasks include:

  • Annual system inspection
  • Checking for leaks or damage
  • Cleaning or replacing filters
  • Flushing the system to remove mineral buildup


In areas with hard water, descaling may be necessary more frequently. This process removes limescale deposits that can reduce efficiency and shorten the system’s lifespan.

Homeowners can perform some basic maintenance, like checking for visible leaks. However, it’s advisable to schedule professional servicing at least once a year to ensure all components are functioning correctly.

Contact Proud Plumbing Today for All Your Instant Hot Water Requirements

Proud Plumbing and Gas offers expert installation and maintenance services for instant hot water systems throughout the Perth metropolitan area. Our licensed plumbers are equipped to handle all aspects of system setup and care. No matter if you’re looking to get an instant gas hot water system or instant electric hot water system, we can help.

We provide:

  • Comprehensive system inspections
  • Professional installation services
  • Regular maintenance plans
  • Emergency repairs


Our team stays up-to-date with the latest technologies and best practices in instant hot water systems. We can advise on the most suitable options for your home or business, considering factors like household size, water usage patterns, and energy efficiency goals. 

Don’t hesitate to reach out for a consultation or to schedule a service appointment. Trust Proud Plumbing and Gas to keep your instant hot water flowing reliably and efficiently.

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