Efficient Hot Water Systems in Canberra and Surrounds

Instantaneous (aka ‘continuous flow’) hot water systems can be limited in their hot water output to just one outlet (such as a single tap or shower), or be sized to multiple outlets. If you want instantaneous hot water for all your hot water points, we will carefully consider what works best for this.

In electric systems, there are a series of heating elements wrapped around the discharge pipework leading to the hot water outlet, and these continuously heat up the water flowing past when the outlet is open. Gas systems work similarly, but with the water passing, on its way to the outlet, through a heat exchanger, heated by a burner.

In both cases, there is no hot water being stored, so no tank is needed. This means that these wall-mounted systems may only take up an eighth of the space that an electric storage tank system does.

For those without mains (natural) gas, it is possible to get systems that run on liquefied petroleum gas (LPG). For those without reliable electricity, it is possible to get systems that ignite the natural gas or LPG using hydropower (energy from the water flowing through the system is turned into electricity to provide the ignition and to operate the appliance).

Just as cooktops and kettles use electric elements, an electric storage tank system has at least one element. It uses this to heat (and keep hot) the water in its tank. The unit can be installed either indoors or outdoors.

This type of hot water system is usually the cheapest option to buy, but costs the most to run – it can comprise a large portion of a household’s electricity bill. If your electricity is on a time-of-use pricing plan, you may wish to consider a storage tank system that heats the water through the night (during the ‘off-peak’), resulting in lower electricity costs. However, because the heated water then has to last all day, you would need a larger water tank than you would for a standard system.

These hot water systems, which are usually a lot cheaper to run than an electric storage tank system, use a gas burner to heat (and keep hot) the water in the tank. They usually have a continuously burning pilot light that ignites the main burner when the temperature at the bottom of the tank goes below a set level. They are typically installed outdoors because of the requirement for a flue.

For homes without mains gas, it is possible to get systems that run on LPG. LPG is typically more expensive than mains gas per unit of energy used, and, for running a storage hot water system, LPG is likely to work out more expensive overall even when factoring in the fact that mains gas comes with a daily supply charge on top of the usage charges.

In NSW, electricity is still primarily generated by coal, making gas storage tank systems a substantially cleaner choice there compared to electric storage tank systems. Though, even in NSW, heat pump storage tank systems may, on balance, be more environmentally favourable than gas, given heat pumps' higher efficiency in providing heat relative to the metered energy input they receive. Heat pumps are so efficient because they work by extracting and moving ambient heat energy, rather than directly converting electricity, or (in the case of gas) stored chemical energy, into heat energy.

By contrast, the ACT generates a small proportion of its electricity demand from solar panels located in the territory, while funding renewable energy generation elsewhere in Australia equivalent to the remainder of its consumption (this is explained further on the Environment, Planning and Sustainable Development Directorate website and in an ABC News article). So in the ACT, even electric storage tank systems can be considered more environmentally friendly than their gas equivalents.

Just as a reverse cycle system operating in heating mode uses a refrigerant gas to extract heat energy from the air outdoors (even if it seems cold outside) and transfer that heat energy to air indoors, a heat pump hot water system does the same but transfers the heat energy to a tank of water.

These systems are expensive to install, but are more energy efficient than electric storage tank systems.

The system has a compressor, just like a reverse cycle system’s outdoor unit, and this creates some noise. So you should make sure to position it away from your bedrooms and away from neighbours. As you may be aware, Canberra has strong noise regulations. Also as with a reverse cycle system, the compressor needs to be in a well-ventilated outdoor area, so do not cover it with screens or clutter the area around it.

Water is circulated between the solar collector panels (which are normally on the roof) and the storage tank (the main tank is usually at ground level, but there may also be a smaller tank on the roof, like there is in the photograph above). The collector panels do not generate electricity, but instead absorb heat from the sun and use this to heat the water passing through them.

This type of system usually uses a larger tank capacity than any other type of storage tank system (even systems designed around off-peak usage), so as to heat as much water as possible when there is more sunlight available. They also come with an electric or gas booster system, positioned between the water outlet of the tank and the input to the property, which further increases the water temperature if sunlight alone was unable to get the tank(s) to the desired temperature.

For a four-person home, one can expect to need 4 square metres of panels. It is very important to have the panels installed in a location where they will be at their most efficient.

The systems are expensive to install, but cheap to run.