Dangers of Too Hot Hot Water Heaters

According to the Public Health Agency of Canada, the 60°C water delivered by most water heaters can cause severe burns in a matter of seconds. Drop that temperature back just a little to 49°C, and it takes two full minutes of skin contact before the same degree of burning occurs.

All this sounds great, until you actually lower the thermostat on your water heating system. Have you ever tried it? That’s when you’ll notice how much more quickly you run out of hot water. A lower tank temperature means you need to mix proportionally more cold with hot water to get water that’s just right for showering, washing dishes and running hot loads in the washing machine.

Then there’s the physical dangers of running your hot water tank too cool. Temperatures lower than 49°C can allow the growth of harmful bacteria, including the kind that causes Legionnaires Disease. But there is a way to make your taps virtually burn-proof and bacteria proof, while also retaining a full measure of hot water when you need it. The trick is a small piece of hardware sometimes called a mixing valve or tempering valve.

I just finished installing a new hot water tank at my house, along with a mixing valve. The model I bought is made by Watts, and cost about $90 at Home Hardware. This sounds expensive until you see the unit. It’s heavy duty, all-brass and comes with the fittings you need to connect to 3/4″ diameter pipe.

All mixing valves work the same way. Scalding hot water directly from the tank is combined with a controlled amount of cold water in the valve itself, depending on how you have it adjusted. The fully hot water in the tank lasts a long time and remains sterile, without ever getting directly to your taps and causing danger. You dial in whatever temperature you want for the hot side of your water system. The Watts valve I used has a locking feature to prevent the temperature control knob from being tampered with.

But not everyone has mechanical access to the source of their hot water. If you live in an apartment building or condo, what flows out is what you get as far as hot water goes. Or perhaps you need very hot water from some taps in your house, while only needed tempered water in the bathrooms. This is where something called HotStop can help. It’s a line of anti-scald shower heads and tub spouts that automatically shut off the flow of water when it gets dangerously hot.

We’ve been using the HotStop shower head at my place for a couple of weeks now, and it does everything it claims to. Turn the hot water on full, and just about the time it’s getting too hot to tolerate, the water trickles to a halt all by itself. A minute or so later, after the shower head cools, water starts flowing again. It’s simple, safe, and costs less than $50. My only complaint is the angle of the shower head in relation to the handle. Used with a separate hose, as we do, the geometry isn’t quite ideal at our place. Right now, you’ll find HotStop at Lowe’s stores.

Hot water is one of the essentials of civilized life, but it also causes a lot of unnecessary suffering each year. It doesn’t have to be this way at your place. A little understanding and a little equipment goes a long way to keep your hot water flowing without getting you into the kind of ‘hot water’ that nobody likes.

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