With a tankless water heater, there’s no question that hot water is slower to appear than through the old storage tank water heater. Waiting on the water to heat also forces you to waste water. Something’s not right when you must waste water in order to save on energy. However, there’s a way to fix this.
Demand systems is a pumping system that allows you to have hot water quickly without having to run it down the drain as you wait. If you shop around, you’ll find that there are quite a few manufacturers of these systems. Research may convince you to try it.
Years ago, there were not any low flow fixtures, and hot water was ready quickly. However, less water was not used. The difference was that the water came out a lot faster, thus producing hot water faster. For instance, a pipe ½ inch around and 63 feet in length contains 1 gallon of water.
If your faucet is set to release 5 gallons a minute, within 12 seconds you’ll have water. With a slower flowing faucet that releases only 1 gallon a minute, the water needs 60 seconds to arrive. In addition, the pipe will be cold unless recently used, and will absorb the water’s heat as it makes its way to you. In cold pipes, it takes longer for the heated water to appear.
With tankless heaters, there’s not a full tank of water waiting to heat. It’s more like a piece of pipe over a burner. To get the water hot, it has to stay over the burner for set amount of time. The water in the center of the pipe won’t be over the burner long enough for heat. First, it has to move through the entire pipe for maximum heat.
This can be remedied by pumping water in a circle from the heater’s outlet through the pipe and cold pipe back to the heater. Turn off the pump just prior to the hot water reaching the faucet and you won’t have hot water entering the cold pipes. Since no water is wasted running down the drain, you now have a green water heating system.
“Demand” systems work through placing a small pump at the faucet furthest away from the heater. These are connected between the cold and hot lines. A device senses temperature increase in the pump that shuts it off. The heated water won’t get into the cold line.
The price tags on the Demand systems range from around $180 to over $500, depending on what your needs are. However, a family of 4 has been shown to save over 10,000 gallons of water annually with this system. So the cost could be worth it.