Translating…
The Problem: Waiting for Hot Water
For this article let’s use a typical house with one bathroom and a kitchen and assume that the bathroom is located the farthest away from where it is heated.
The hot line starts at the heater and goes first to the kitchen and then to the bathroom. Typically a water heater is located at some distance, 30 ‘to 40’ or more, from the farthest fixture.
If more than an hour has passed since the last time someone used hot water, the hot line will have cooled off. This cool water must be removed from the line before hot water reaches your faucet.
In many homes this is done by turning on the faucet and letting it go down the drain until it is hot.
Wasting water, money and time.
You can use your existing cold line to circulate the cool water back to the heater. In order to do this you will need a pump (otherwise known as a circulation pump) and a flow sensor at the water heater, and a crossover valve (also known as a bridge valve) between the hot and cold water valves under the farthest sink .
In our example, the pump and flow switch is installed on top of the heater and the crossover valve is installed under the sink in the bathroom. As the hot water is drawn from the tank by the circulation pump it pushes the cool water back through the cold line to the heater to be used again.
How It Works
The simple version : Turn on any hot water faucet in the house for 1 second and then turn it off. Wait about 10 seconds and you will have hot water everywhere you need it.
More details : Turning on the faucet for a moment activates the pump and it starts pushing the cool water through the crossover valve back to the heater. When 95 degree water gets to the sink the crossover valve closes.
The flow switch monitors flow and only turns on the pump when there’s a demand. Once the crossover valve closes the flow switch will turn off the pump unless there is a faucet on.
Why should you consider doing this in your home?
If you wait longer than 45 seconds for hot water in your home, a circulation system like the one described above can pay for itself in a couple of years in water and sewer costs.
Of course the benefit of drastically reduced wait times (convenience) is harder to assign a value.
And in the bigger picture anything we can do to save water and reduce waste should be considered.