Having instant hot water could save all that water that gets run down the drain while people wait for the hot water to reach the fixture.
In areas suffering through drought problems instant hot water can help.
If you are suffering through drought conditions, then you already know that every drop of water is precious. There are of course, many ways to save water. Most methods of saving water involve giving up something or suffering in some manner. You have to give up washing the car, or watch your lawn die. Low flow toilets and shower heads are not a great deal of fun either.
Instant hot water is convenient too!
However, there is at least one instance where conserving water can actually provide you with a convenience. Take your hot water for example. You waste a lot of water waiting for hot water to reach the shower. I suppose there are some people who don’t wait for the hot water to arrive, and just jump into the cold water…not me though.
Having instant hot water could save all that water that gets run down the drain while people wait for the hot water to reach the fixture. We are talking about a significant amount of water too. And remember, in areas with drought problems, every drop counts!
Manufacturers of hot water circulating systems claim as much as 16,000 gallons per year in water savings by using a hot water circulating or on demand hot water system. Even if we are conservative and estimate 10,000 gallons per year in savings, for a small 25,000 home community, the total water savings would be around 250 million gallons per year. In drought affected areas that’s significant.
What kind of instant hot water system is best?
Traditional hot water circulating system / pump
There are several types of systems available, and like everything else, they all have their pros and cons. The traditional full time circulating system requires a return line from the last fixture back to the water heater, and usually isn’t suitable for a retro-fit application. In most cases it’s quite expensive to install new piping in an existing home. However, if you are willing to spend the money to install a return line, you will be rewarded with nearly instant hot water.
The downside to this type of system is that they use a lot of energy. Keeping the piping full of hot water makes the water heater work harder, and not only wastes a lot of energy, but can reduce the life of your water heater. You have to pay for the energy to keep the pump running too. Great for helping with drought problems, but a waste of energy.
Often these systems are used with a timer that shuts the pump off during times of little use, which helps reduce the wasted energy somewhat. Traditional hot water circulating systems cannot be used with tankless water heaters, since they would either not be able to pump enough water to turn on the heater, or they would keep the heater on all the time.
Warm water circulating systems bring little drought relief and waste energy
Another type of system uses a small pump and valve under a sink where instant hot water is desired. The inlet of the pump is connected to the hot water pipe, and the outlet is hooked through a valve to the cold water pipe. The pump turns on whenever the temperature of the water in the hot water pipe falls below about 95 degrees, and then turns off when the temperature reaches a much higher temperature.
As with the traditional circulating system, this type of system uses a lot of energy, since it keeps the hot water piping above ambient temperature, making the water heater come on more often and consuming much more energy. It tends to fill the cold water pipe with warm or tepid water. As with most circulating systems these will not work with tankless water heaters. There are a number of manufacturers that sell this type of system including Grundfos, RedyTemp, and Laing.
The best drought hot water solution; the hot water on demand system
A better type of cold water return type system is known as an on-demand hot water system. With a demand system you must demand hot water by pushing a button or activating the pump in some other way.
Once activated the pump sends hot water to the fixture rapidly, and when the hot water arrives at the pump, it shuts off. This prevents the cold water pipe from filling with warm or hot water. No water gets run down the drain, and the hot water arrives faster than normal.
On demand systems will work with tankless water heaters as long as they have enough pumping capacity. Metlund and Chilipepper Sales both manufacture such systems.
Tankless water heater problem
It takes significantly longer to get hot water from a tankless water heater than from a conventional storage water heater. That is because with the storage heater as soon as the faucet is turned on hot water is on its way. But with the tankless water heater there is no hot water already waiting… the heater has to make it first, and so it takes longer to get hot water at the fixture.
Longer waits mean more water run down the drain and increased drought problems. So if you have or are going to install a tankless water heater you really need a hot water on demand system, or at least it would help with the drought problems.
Check with your local water company, some water companies are offering rebates to customers for purchasing on demand hot water systems.