top of page
  • Writer's pictureRory McEwan


RMC Plumbing Services is asked this question many times a week, and the answer all depends where you live and how much hot water you need a peak times.

Most homes of 10 years or older are built with storage hot water systems, this was done due to designers believing having stored water ready to go was the right thing to do.

The plumbing authorities and Plumber's Licencing Board brought in a by-law which was designed to protect families which ensured that the hot water delivered to any shower, basin or bath have a maximum temperature of 50' c. This was brought in to prevent the very young and the older people from getting scalded with extremely hot water causing third degree burns. Through extensive testing it was agreed that hot water at 50'c can burn the very young and older people but it will not cause scarring therefore reducing risk.

The methods of controlling the temperature of hot water is to install "TEMPERING VALVES" on all hot water supplies into bathrooms. These valves are set up when the building is completed. The problem with tempering valves are they are consumable as they corrode with the impurities in our water causing failure within the valve diminishing hot water delivery.


Because of our quality of water in the South West of Western Australia i.e. hardness of water and impurities in the water delivered through our water meters this alone dictates what Hot Water System we should be installing!

If you have very hard water with a rating of 120m/g per 4.5litres of water you should be using a Continuous Flow HWU i.e. Rheem, Rinnai, Bosch, Dux or Therman.

All of these HWUs do not store water and are less likely to corrode.

If your water hardness rating is below 120 m/g per 4.5litres you can install a Solarhart, Solar Panel system or a storage type HWU.

With high hardness rating with storage HWU the heated water that is stored can be very corrosive when the water is continually heated when not being used.

So what is recommended by RMC PLUMBING SERVICES our advice would be to install a Continuous Flow Hwu as these units are rated at 6/6 energy rating which means they are economical to run and have a great warranty.


The economy of running costs

The purchase cost of unit

The ease of installation.


Requires power supply to run

Cost of installing power point

Pre-set temperature of 50'c on domestic installed units

So this information should assist with selection of your next HWU.

Do not forget that RMC PLUMBING SERVICES are the specialist in supplying and installing all types of HWUs.

Free quotes Free advice and Free friendly service.

Call Rory now 0412287673

99 views0 comments

Recent Posts

See All


bottom of page