There are many ways to provide hot water in the home. These include:
For an overview of options see the advice from Renew (formerly the Alternative Technology Association), either in the web page or their downloadable Efficient Hot Water booklet.
Traditionally people wanting an environmentally friendly way of getting hot water chose solar hot water systems using flat panel or evacuated tube collectors. When solar PV was expensive it was wasteful to use it to heat water since only around 20% of the energy that falls on a PV panel is converted to electricity.
However as the cost of PV has reduced there is increasing interest in diverting surplus PV to reduce water heating costs. This is also seen as a way of getting
better value from an existing PV system. Instead of exporting surplus energy and getting a low feed-in tariff the energy is used to pre-heat water saving the cost of purchased electricity.
Solar hot water system may still be desirable (particularly if designing a house from scratch) but another reason why using surplus PV to heat hot water may be more cost effective is that if it uses an existing hot water service, no plumbing is required.
If you are planning a new-build or your existing hot water system needs replacement we recommend considering all the options set out in the Renew booklet.
However if you have an existing electric hot water system in good condition making the most effective use of it with tariff 93 (whether or not you have solar) will be the cheapest and easiest way to save money. The options are explored in more detail in our fact sheet on Saving money on hot water with tariff 93.
¹ While the site remains active, some (slightly dated) Tasmania specific information is available at https://tasrenew.org.au/solar/
² More detail and historical info on this topic is available at https://tasrenew.org.au/metering/
