Position and output temperature restrictions

Where to position your hot water system

Choosing the right position is very important when picking a site for your hot water system. A lot of efficiency is lost when the wrong place is chosen. Efficiency isn’t the only thing you need to think about when choosing where to put your hot water unit though.

Setting the tank's temperature to 60°C prevents the growth of bacteria.

When placing your hot water heater, you have to consider the type of system you are installing. For example, there may be restrictions in your area regarding the use of heat pump hot water systems due to noise levels. This is more of an issue in denser city areas where houses are closer together – generally speaking, heat pumps make about the same amount of noise as air conditioner units. If in doubt, check the decibel output levels (dBA) on the model you are considering, calculate the distance to your neighbours’ doors and windows and consult with your state’s noise control authority.

You may also need to provide drainage for water that comes out of the T&P valve and discharge pipe. This may require adjustments to your current plumbing, or a redesign in your plumbing blueprints if you’re building from scratch, but is a necessary concern. Likewise, you should adhere to the manufacturer’s instructions regarding how much clearance the unit needs around it and how high off the ground it can or should be installed when planning your home.

Tempering valve 
A tempering valve contains a thermostatic element to limit the temperature of the water at the tap.

Many of these requirements will come from local council ordinance laws or from a body corporate. Make sure to check with them before you plan so you know about any restrictions or special requirements beforehand.

When positioning solar collectors, check your roof will support the weight. This is generally not an issue if all you’re installing are the collectors; adding a frame to angle them will weigh a little bit more. Put the tank up there too and there’s a good chance your roof will need added reinforcement. While not a restriction, it also makes good sense to ensure that your solar collectors are facing north to get the most sun.


Temperature restrictions

It is mandatory in all states that all storage tank hot water heaters are set to heat the water inside them to a minimum of 60°C. This is to kill any bacteria living in the water, as it will be sitting in one place until drained from the tank through the hot water pipes. Be aware that setting the temperature much higher than this may also increase your running expenses.

Another state based law that has been adopted country-wide is the regulation on how hot the water can be when it comes out of your showers and taps. To prevent scalding injuries, hot water from taps shouldn’t exceed 50°C.


The difference in temperature between the requirement for your tank (60°C) and for your taps (50°C) will solve itself in some instances due to the heat that’s lost as the water travels to the taps, but the most common solution to this issue is the installation of a tempering valve.

A tempering valve contains a thermostatic element. When hot water is drawn into the valve, it tests the temperature of the water from the hot inlet and allows in enough cold water to bring the temperature down to the set level. A tempering valve will often be installed along with your hot water heater, but you should make sure this is included in the quoted price for installation.