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Hot Water

Types of Hot Water Systems

Hot water can use many different energy sources , gas ,electric, wood and solar.  Please find below a detailed explanation of possible choices for you the customer.

These systems store heated water at a constant temperature in an insulated tank, ready for use. The water is reheated by a Gas flame when the temperature falls below the thermostat setting. Internal and external models are available. Internal models require a flue. These systems are rated for their energy efficiency with an energy star rating system. The more stars the more energy efficient. Their storage capacity and recovery rate determines how much hot water they can deliver. Because gas hot water systems heat much faster then electric systems, they usually require a smaller tank to produce the same amount of hot water per hour.

Being a Green Plumber we highly encourage the 5 Star Efficiency Units. Gas is also a clean energy source.

5 Star Efficiency Unit                               3 Star Efficiency Unit
5 Star Efficiency Unitimg_013

GAS CONTINUOUS FLOW SYSTEMS Continuous flow or instantaneous hot water units as they are sometimes referred, heat water as required, so they never run out. They are sensible method of water heating, since you only pay to heat the water you use. These are much smaller in size than storage systems plus they can be installed externally or internally with a flue. They are rated by the volume of hot water they can produce per minutes, which is usually 10 to 26 litres. The more hot water you use the higher the capacity unit you will require. Gas units generally require a large supply line potentially adding to the cost of installation. Continuous flow systems are often popular for units or homes with limited space.

Introducing the most energy efficient systems on the Australian market. - the Rinnai Infinity 26 Enviro. Technically they are known as "condensing unit", but what is important is that they use considerably less gas to produce the same quantity of hot water as standard systems.


  • Australia's first 7 Star equivalent Hot Water System - 26 Litre
  • Use less gas, substantially reducing running costs
  • Around 1/6th of the Greenhouse Emissions of a standard electric hot water
  • Also available as a 32 Litre - 6.8 Star equivalent
  • 12 year warranty on the Heat Exchanger

In electric storage hot water units, water is heated in an insulated tank by an electric element, like a giant kettle. Units that are less then 160 litres generally use continuous rate. They are ideal for households where smaller amounts of hot water are used throughout the day rather than a large amount being required at one time. Systems greater than 160 litres capacity generally use off-peak electricity. With an off peak system, water is heated overnight to provide adequate water for the following day, reducing your total electricity charges over that of a peak system. Electric Storage Units may even be phased out in the future and be replaced with either a Solar Electric or Heat Pump.


Solar hot water systems use the suns energy to heater water. They are generally the cheapest system to run, however their high purchase cost means they have an average pay back period of approximately 5-7 years, depending on what rebate is available at the time of purchase. All solar systems come with a gas, electric or solid fuel booster to supply adequate hot water during periods of low sunshine. Solar collectors are located on the roof of the home and connection to a storage tank on the roof or ground level. Ground level tanks are sometimes preferred because they provide a clean roofline. Solar hot water systems are environmentally friendly alternative to gas and electric systems and government rebates are offered in many states in an effort to encourage their use.

Kelly Plumbing supplies and installs a range of Solar Hot Water Systems.

HEAT img_018PUMPS:

The environmentally friendly Heat Pump has been specifically designed for Australian environmental conditions by cleverly removing heat energy from the ambient air and storing in the water tank. In cold conditions the Heat Pump has a unique freeze mode which activates a booster element to ensure plenty of hot water is available, even on the coldest winter nights

BOILINBoiling waterG WATER:

No longer do you or your employees have to fill urns or kettles and wait for the water to boil. As boiling water units are a common fixture in many work places and domestic properties, we are highly trained and knowledgeable in the repairs and new installation of Boiling Water Units. This makes it ideal for clubs, factories; schools, lunch rooms, kitchens or anywhere boiling water is required.

Types of solar hot water systems

A solar hot water system takes energy from the sun in a similar way that a hose does when it is left lying in the sun € but the pipes in a solar hot water system have been designed to work much more efficiently than a garden hose. It is critical that each unit is sized correctly for your individual needs, as can cause troubles if either under sized or over sized. Call and make an appointment for a highly trained technician to attend site and best suggest a system for your needs.

There are 3 types of solar hot water systems:

  1. Thermosyphon / Roof Mounted System.
  2. Split system (or €forced circulation€).
  3. Evacuated Tubes

Thermosyphon / Roof Mounted system

This is the most common system available. It consists of roof-mounted solar collectors with a storage tank positioned immediately above the collectors. As the heat from the sun is absorbed through the collectors, the water inside becomes hotter and lighter, expanding and rising upwards into the tank. The colder, heavier water is drawn down into the bottom of the collector where it is heated, causing it to move upwards. This circular heating motion is called the thermosyphon effect. The greater the difference in temperature between the water in the collectors and the water in the storage tank, the faster the flow between them. A closed circuit system separating the collector circuit from the tank is available for areas prone to frost

Split system (or forced circulation)

For householders who prefer their tank at ground level, this system has the solar collectors on the roof and the storage tank on the ground. These systems require a small electric pump to circulate water through the collectors into the storage tank. As a result, this system is generally more expensive to buy and operate than a thermosyphon system. Furthermore, the moving parts in the pump can wear out over time meaning these systems require more maintenance than a thermosyphon system. The pump is regulated by a controller, which reacts according to the difference in water temperature between the collectors and the tank. The controller unit also acts as a frost protector by sending warm water from the tank into the collectors when it senses that the water is reaching freezing temperatures.

Split system

Connect Solar Hot Water to your Wood Heater or Stove

Solar Hot Water and Wood Heaters or Stoves make a perfect combination. With a correctly sized solar hot water system, the sun will provide at least 70% of households hot water needs. However, in the cooler months solar needs boosting, and this is the time of year when you use your wood heater to keep warm.


Why not tap some of that heat going up the flue to heat your water?

Where houses are off the reticulated gas grid it make good sense to utalise your wood heater or wood stoves fitted with water jackets, otherwise known as wet-backs, to provide hot water booster. Kelly Plumbing has extensive knowledge in this area and can tailor a system to best suit your requirements.

For more information you can call our advice line on (03) 5447 1596

Hot water

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Phone:  (03) 5447 1596