Many workplaces have hot water available for hand washing, general kitchen use and showering. This service is supplied from what is known as a 'domestic' hot water system. Hot water is costly to generate, so it's important that it is produced and used efficiently. For example, supplying just 100 litres of hot water per day can cost $300 each year and generates three tonnes of greenhouse gases. The simplest change you can make is to reduce hot water consumption. This section provides an overview to heating water for domestic hot water uses in sites such as Offices, factories, restaurants and shops, and highlights the opportunities to improve the hot water service and save on running costs. It focuses on smaller, local hot water systems rather than larger centralised systems. Taking Action 1.Stop excess hot water going the drain. Install AAA rated showerheads or flow restricting valves on taps. They not only save on energy and water bills, but also reduce the risk of running short of hot water, and may save capital costs by reducing the size of hot water system required. AAA rated showerheads can simply replace existing ones and cut water consumption from about 15 Litres/minute to 7 Litres/minute without reducing the quality of the shower-up to a 50% reduction in energy consumption. AAA rated showerheads cost between $15-80, while aerators and flow regulators for taps are in the range of $6-30. Repair dripping taps. They waste water and energy. Use separate hot and cold taps rather than a single lever tap which will tend to be used in the middle and some hot water will be used when cold water is sufficient. 2.Can the existing system be improved? Install an adjustable thermostat to provide more control and to ensure water is not being heated to unnecessary temperatures. Most units have their thermostats set at 80ºC but could be economically set to 60-65ºC. Insulate pipes between the tank and taps. Insulation should be at least 10mm thick, especially the first two metres leading from the hot water system as this is where most heat energy is lost from the pipes. Upgrade the insulation of the hot water tank (electric tanks only) by wrapping extra insulation around it. The heat loss from a small electric hot water system and its fittings costs around $70 each year. Studies indicate that an $80 hot water cylinder wrap should save a typical household $65 per year in electricity costs. Install the hot water tank as close as possible to the usage point, to minimise heat loss from pipes. Consider removing or switching off unnecessary hot water system units, e.g. if a boiling water unit is installed above a sink, an outlet with a mixing valve could be fitted to supply the modest amounts of domestic hot water needed for washing dishes much more cheaply and efficiently than a separate hot water system.

Save 80% of your water heating energy costs by conserving hot water and using the appropriate hot water system. Halve hot water consumpt-ion by installing AAA rated showerheads, water saving aerators on taps, or in-tap flow regulators. Maintain and repair taps and hot water pipes. Leakages cost money. Save energy by upgrading tank and pipe insulation.

3.What's important in a new system?

• Water heaters eventually need replacing and when they do, are often replaced with the lowest initial cost option, which is usually a greenhouse intensive electric system.

However, an investment in a more efficient system such as a heat pump or solar system can result in large ongoing energy savings and a rate of return of about 10%.

When making the change, consider:

1. Sizing the new hot water system to accurately meet your needs.
2. The Technology Table that follows provides details on available systems, their energy efficiency and greenhouse intensity. Use this table to find out about your existing system and new options.
3. The storage of hot water should also be considered as this influences the greenhouse intensity of the system.