How hot should you be keeping your hot water tank’s temperate set to? Have you ever given it any thought?
There is an ongoing debate about how high or low to set a hot water heater’s maximum temperature, both sides with compelling reasoning behind their recommendation. This article will attempt to briefly explore both sides, but will leave readers to make their own decisions on the matter.
Many Canadian government agencies currently recommend setting a hot water heater’s maximum temperature to 49 C. This lower temperature is recommended for two main reasons: (1) It can help prevent scalding, especially of small children or senior citizens, and (2) it reduces resources – and therefore cost and environmental impact – required for residential water heating.
Conversely, the World Health Organization recommends a higher maximum setting of 60 C to ensure the water-borne bacteria known as Legionella is killed.
Legionella is responsible for a certain type of pneumonia called legionellosis, which can be fatal in up to 30~50% of cases.
While Legionella thrives and multiplies in still water between 32 ~42 C, the oft-recommended 49 C is insufficient to kill the bacteria – only its further growth is prevented. The WHO-recommended 60 C, however, is sufficiently hot enough to kill 90% of the bacteria within 2 minutes.
A recommended “best of both worlds” solution is to set the hot water tank to 60 C to kill the Legionella, then have scald-prevention mixing valves installed in sinks, showers, baths, and other points of human usage. However, this solution doesn’t impact the cost associated with heating the water in the tank in the first place.
Homeowners will ultimately need to research both sides of the issue and decide what makes sense for their home and family. If we at the Gentlemen Plumbers can provide any assistance with your hot water heater, feel free to call us 24/7.
Reference: The Canada Safety Council