Perception is reality and nowhere is this truer for us at Whywait Plumbing than when dealing with the issue of hot water temperature and the possibility of a 
serious hot water burn.
Everyone has a different perception of how hot they want their hot water whether it is for cleaning or sanitation or personal hygiene use.
Recent research in the United States from the Johns Hopkins Bloomberg School of Public Health, confirms hot water heater temperatures are too high.
In Australia, most manufacturers preset the thermostats for hot water heater temperature at 60-65 degrees. This is dangerously high for a significant proportion of homes, presenting a scald hazard particularly for young children and the elderly. This is because literally hot water burns like fire because:
At 60°C, a serious burn can happen in 1 second
At 55°C, a serious burn would take 10 seconds
At 50°C, a serious burn would happen after 5 minutes
It is estimated a serious hot water burn causes an estimated 1,200 hospital admissions and 50 deaths per year. Young children and elderly adults have thinner skin which burns more quickly putting them at increased risk.
In Queensland, it is the law that hot water delivered to bathrooms used primarily for personal hygiene purposes be regulated by use of a tempering valve or a thermostatic mixing valve that does not exceed 50°C. This is due to the fact that in 1995 the laws were changed requiring tempering valves to be installed on:
all new homes having a hot water system installed
replacement or upgrading of an existing hot water system
or when moving an existing hot water system to a new location on the property
However, homes built before 1995 will frequently still have hot water being delivered at 70°C. It is estimated that 37% of homes still have older electric or gas heaters delivering hot water that presents a scald hazard that will cause a serious hot water burn in one second.
Frequently these homes are rental properties. Many landlords and real estate property managers are unaware that recent litigation has placed a ‘deed of care’ onus on them to ensure the safe delivery of hot water in domestic bathrooms used primarily for personal hygiene purpose.
The installation of a tempering valve is an acceptable solution to hot water scald prevention. Delivering hot water at a consistent temperature is difficult without a tempering valve. This is due to the fact that as a hot water tank is depleted through use then replenished and reheated, the water temperature will not be constant throughout the tank.
Despite a perception by many people, a hot water service thermostat is not designed to provide precise estimates of water temperature. Its purpose is to begin heating when the temperature drops below a set level and turn off when it reaches a set level. Without a tempering valve installed it is almost impossible to assess the exact temperature of hot water delivered from a tap.
The advantage of a tempering valve is that guesswork is eliminated as tempering valves are designed to blend hot and cold water to deliver mixed water at a constant temperature and thus reduce the risk of a serious hot water burn.
Unfortunately for plumbers, property managers, homeowners and property investors hot water has increasingly become a legal minefield with the duty of care provisions.
It is for this reason Whywait Plumbing recommend that you install a tempering valve and maintain it compliantly with annual testing.
