There are many devices that can help you save water in the home. These include low-flow faucets and toilets, as well as toilet tank adapters. Check with your water company. Many offer free water-saving tools and rebates on water-efficient toilets.
In order to get hot water at the faucet faster, some people with large homes put in recirculation systems that keep hot water constantly circulating in the pipes. This gives the user almost instantaneous hot water at any fixture in the house, saving both time and water. However, this also wastes a lot of energy, since hot water circulating through the pipes continually loses heat—even with insulated pipes, as explained above. It also takes energy to pump water through the system, though this energy loss is much smaller than the loss from escaping heat.
Things can be slightly improved by adding a timer to control the pump, which will cut run time by about two-thirds. Somewhat better results are achieved by adding a thermostat to keep water temperature in the lines down to 105–110°F. Best of all is demand pumping, which turns on the pump only when you want hot water, cutting run time to minutes daily instead of hours.
An improvement on demand pumping is a device installed under the sink that circulates water from the hot pipe into the cold pipe and back to the water heater. Examples include the Chilipepper and the Metlund Hot Water D’MAND System. When hot water arrives at the device, it automatically switches off and hot water is supplied at the tap. This doesn’t require the extra pipe runs used by other recirculation systems, further reducing heat loss.
Drain Water Heat Recovery
When we shower, we heat cold water and then run it over ourselves and down the drain. A drain water heat recovery (DWHR) unit captures up to 60% of that heat and puts it back into the shower water or the hot-water tank. These units can also triple the recovery rate of a water heater, making hot water available much sooner and extending the life of the heater.
Drain water heat recovery units all have the same basic design. They consist of a central core, through which warm wastewater flows, wrapped with copper heat exchanger tubing, through which the cold incoming water flows. Fresh cold water is thus preheated before it goes to the water heater—or better yet, to the cold-water side of the shower. (Preheating the cold shower water means you need less fuel-heated hot water.) It’s a relatively simple system with no moving parts and no maintenance, but it does require sufficient room below the drain to allow gravity to work; it may not be usable in a single-story home without a basement. Some brands are Power Pipe, ThermoDrain, and Retherm. Utility rebates are available in several states, paying up to 40% of the cost of these units.
Select a Water Heater That Is Compatible with Your Needs
Now that you’ve done your homework and reduced as much waste as you can, you may still need to buy a new water heater, but you probably won’t have to get a big, expensive one. The first step in deciding what type and size of heater to buy is to determine how much hot water you really need. If you are considering sizing your water heater to accommodate more people than live in the home at present, don’t get a bigger tank. Instead, get the same-size tank with a bigger burner.
To select the right size of water heater for your household, first figure out how much water your family needs during the busiest hour in your house (for instance, when everyone is getting ready to leave in the morning).
Then look for a water heater with a first-hour rating (found on the EnergyGuide label) that matches your peak-hour demand. This rating tells you how many gallons of hot water a given model can deliver in an hour, starting with a full tank of hot water. You may also want to check the first-hour rating of your old water heater; the EnergyGuide label, the nameplate, or a call to the manufacturer (providing the model number) should get you the information.