We all know that over heating hot water is a waste of energy money.
However, water that is not hot enough can be a heath risk.
Looking at the numbers:
Water at 160F (71C) will physically damage the human body by scalding. That is way too hot.
We humans cannot stand temperatures of 140F (60C). Your body will not let you hold your hand in water that is 140F. As an engineer, I have used this fact to determine if machinery is running too hot. If I can hold my hand on an electric motor, I know it is below 140 and running OK. If it is too hot to hold on to, it may be over loaded.
Water at 140F will kill 90% of the bacteria in it in 2 minutes.
Water at 122F (50C) will kill 90% of bacteria with in 2 hours.
Warm water in the range of 95-113F (35-46C) is perfect for growing Legionella bacteria. This is the bug that causes Legionnaire’s disease.
Most folks like their hot tub or spa to be in the 95 to 105F temperature range. That’s about the same temperature that the bugs like. That is why Chlorine, Bromine or other chemical must be used make spa water healthy.
You will see articles suggesting that for energy conservation a home hot water heater should be set in the 115-120F (46-49C) range.
We have one U.S. government agency saying keep it at 140F for your good health and another U.S. government agency saying set it at 120F to save energy!!!
120F might not be hot enough for your health. If there are dead ends in your piping, where the flow stagnates, bacteria could grow inside your home hot water system.
The general recommendation for hot water heaters that are in public or commercial buildings is 140F (60C).
I really enjoy a hot shower and shave in hotels because they have plenty of hot water. They keep it hot to avoid the liability risk of water born disease.
A good choice for home hot water tanks is 130F (55C). Adding an extra blanket of insulation on the tank will slow the heat loss.
If you have problems dreaming about the little bugs in your pipes run the hot water at each faucet for a few minutes once a month and send them down the drain. Yes, that is a waste of hot water, but if you sleep better, it may be worth it to you.
Click here for a free money saving report titled HOW SAVE MONEY ON YOUR NEXT HEATING BILL
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