What is your hot water tank’s maximum temperature set at? Perhaps more importantly, what should it be set at?
There is much debate around this issue as there are significant pros and cons to setting your water heater higher or lower. This article does not provide a definite mandate for hot water settings, but instead attempts to provide information from both sides of the argument.
First, why might you want to set your hot water tank to a lower temperature? Your gas bill would be an obvious place to start. Obviously, the lower your maximum temperature setting, the lower your utility bills will be. This is also a benefit for those attempting to ‘go green’ in their homes. Another, and perhaps more urgent reason to set your temperature lower would be to try to prevent scalding. When hot water heaters are set to higher temperatures, more caution must be exercised when turning on your taps to bathe or wash. Small children and the elderly especially can suffer severe burns and other complications from high water temperatures.
However, there is a compelling argument for keeping your hot water tank’s temperature set higher: preventing water-borne disease.
Though modern plumbing systems help mitigate water-borne diseases so well that most of us in Canada never even think about them, the Legionella bacteria is known to grow in standing water within even our modern systems. Legionella causes a type of pneumonia in its victims, and is fatal in up to 30~50% of cases.
Legionella thrives and multiplies in still water at 32 ~ 42 C. Currently, many Canadian government agencies recommend keeping hot water heaters set to 49 C, however this temperature is sufficient only in preventing the bacteria from multiplying – it is not hot enough to kill them. The World Health Organization recommends keeping hot water heaters at 60 C, which is hot enough to kill 90% of Legionella within 2 minutes.
For those concerned about scalding problems, anti-scald mixing valves can be installed at human points of use, such as sinks, showers, and bathtubs. Though while these may be sufficient to mitigate burns and related complications, they unfortunately will not mitigate gas usage associated with heating the hot water tank.
Ultimately, home owners will need to research and weigh both sides of the argument then choose what they believe is in their best interests. If our plumbers can be of any assistance with any hot water heater issues, don’t hesitate to give us a call – 24 hours a day!
Reference: The Canada Safety Council