Indian Time - A Voice from the Eastern Door

Correcting a Common Error: Don’t Set Your Water Heater Temperature Too Low

Last week, an article in Indian Time recommended setting the temperature of your water heater to 120 degrees (F) to save energy. I would like to direct your attention to the potential for Legionella bacteria growth at such a low water storage temperature.

Please see en.wikipedia.org/wiki/Legionella on Wikipedia.

Also see the recent news about the outbreak in Quebec City http://www.cbc.ca/news/health/story/2012/09/14/legionnaires-new-cases-quebec-city.html

I see this a lot in my profession as a mechanical engineer. People trying to reduce costs.

There are no studies that indicate drinking water with the Legionella bacteria causes any illness, but the risk of infection is when you inhale steam or water vapor with the bacteria in it (during a shower). Most healthy individuals are normally not at risk, but elders and children with weaker immune systems are. For the people at risk it can cause severe illness and death.

I always recommend that domestic water should NOT be stored at any temperature less than 130 degrees F to reduce/eliminate the risk (and in no instance less than 125degF).

To prevent/reduce the risk of scalding a Thermostatic valve can be installed under any sink, tub or shower, or at the water heater to reduce the temperature to a safe level (less than 120 deg F). Thermostatic valves can be purchased at most home improvement stores and installed by most DIYers.

To reduce energy consumption (standby loss) of electric water heaters, a water heater blanket can also be installed easily.

Other fuel fired (propane or oil) water heaters are never to be modified, covered with such a blanket, as it is not designed to be modified or in close proximity to any materials/combustibles and usually require minimum clearances per the manufacturer’s owner’s manual.

Niawenkowa,

Karoniahere

Jeremiah Point, P.Eng., LEED® AP

Owner

Point Engineering

Kawehnoke, Akwesasne