Waiting for hot water at the sink or shower can waste thousands of gallons every year.
Over the past two decades hot water on demand systems have flourished. These systems are now simpler and cheaper and installation has become something that many DIYers can do themselves in an hour or two.
Auxiliary water tanks: When hot water on demand is mentioned, some think of a small auxiliary water heater placed beneath the sink that provides hot water at all times.
It’s important to keep in mind that these units usually only handle one sink. If you have three or four sinks you’ll be looking at a cost of at least $2,000 in heating units and electrical installations.
Pump systems: Our idea of hot water on demand is a bit different than adding tanks. Why not? We’re guys … we like adding motors instead. Also, our choice of new technology utilizes the systems once used by only the wealthy, but with a couple of cool twists. There are two types that we like:
Grundfos Comfort System: Our first choice is one that involves the installation of a motor at the water heater and a small plastic pipe under the sink known as a crossover.
First, a small high speed, low volume (extremely quiet pump) is added to the outgoing hot water line at your water heater. We took about 20 minutes to install ours. The pump is regulated by a simple timer that causes it to run during those times of the day or night when you feel you will want hot water on demand.
We had to use an extension cord to provide 110 volt power to our unit. The pump can be set up to run for as little as 15 minutes once a day or 24/7.
There is no need for a secondary hot water line. Instead, there is a 6-inch-long plastic “crossover” pipe that connects to the faucet that lies farthest from the water heater — and thus affecting all fixtures in between.
The crossover connects the hot and cold water lines together and contains a check valve so that the cold water won’t back up into the hot water line. The crossover is also thermostatically controlled and when it senses cold water in the hot water line it opens and lets the water silently run into the cold water line (and back into the water heater).
This simple process continues until the hot water arrives at the faucet. Instant hot water at every location in your home with two simple additions — a pump and a crossover. When the crossover senses the heat it shuts off. The process repeats when the water cools (as long as the timer is set in the on position). What could be simpler?
The Metlund D’Mand System: This on-demand system works especially well with tankless and hybrid water heaters.
In fact, it is the only one we know of that does. This system differs from the Grundfos in that it requires the pump to be installed under the sink.
Interestingly, the pump, thermostat and the crossover in the Metlund unit come in a single package (as a combined unit) making installation quicker and by far the least complicated. As with the Grundfos, the Metlund needs a 110-volt power source. You will probably have to add one because we don’t usually find outlets under sinks.
A manual switch is provided so the pump can be turned on only when wanted. An optional remote turns the unit on from anywhere in the home.
Metlund’s midpriced unit, the S-70, runs about $400 with one remote control and one manual switch. Check it out at gothotwater.com/default.asp.
The Grundfos kit with a pump and a crossover retails for about $450.
Both of the systems we have mentioned recommend a single installation. However, in our home we have two crossovers, because the water heater lies in the middle of our plumbing system.
For tips from James and Morris Carey, go to www.onthehouse.com or call the listener hot line, 800-737-2474. The Careys are also on KRKO (1380-AM) from 6 to 10 a.m. every Saturday.
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