When the pump is activated, it will pump cooled water in the hot water pipes back into the cold water pipe and push it back toward the water heater, creating a temporary loop as the water heats up.

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A minor drawback with this type of system is that the loop pushes water into the cold side; most distant fixtures will initially have warm water in the cold water pipes when you first run it.

Some systems also offer motion sensors that sense the flow of water automatically, turning on and shutting off automatically. Either way, having hot water on demand is an excellent option for saving water and conserving energy.

Most models come with timers and often built-in sensors that will turn on when the water temperature drops below a set temperature. This under-the-sink hot water recirculating pump will require power under your sink to operate.

Cooled water does not get wasted by going down the drain as you wait for hot water to arrive; it is kept in the loop and sent back to the water heater for heating. When the water comes through the hot water pipe, reaching the desired temperature, the pump shuts off, and the hot water runs out of the faucet rather than looping back through the cold water pipes.

Hot water recirculating pumps save water, save money, and conserve energy. They are particularly helpful in places where water is in short supply.

The system and the installation costs by a plumber may be pricey upfront, but it should save you money on your energy and water bills, conserving energy and water in the long run. These systems are even more beneficial in places that have water shortages, like drought-prone locations, desert climates, and areas that have more expensive water costs.

A recirculating pump is installed in the plumbing lines to create a loop that slowly and constantly circulates the water in the hot water pipes back into the water heater for reheating. When you open a faucet or turn on a shower, hot water is in those pipes, so you don't need to waste water down the drain waiting for the water to heat up.

For this configuration, the pump is located above the water heater, and a check valve is located under the sink, furthest away from the hot water heater. The pump pressurizes the hot side of the system and, through the bypass valve under the sink, pushes the hot water into the cold water system, creating a hot loop.

Depending on the size of your home and the length of the plumbing pipes, some fixtures may require several minutes before hot water arrives from a water heater that might be located some distance away. If you are environmentally conscious, wasting hundreds of gallons of water while you wait for hot water to be delivered isn't acceptable.

If you are tired of waiting for hot water or don't like the idea of wasting water, consider installing a hot water recirculating system.

Water recirculating pumps can last five to 15 years, depending on the quality of the product and if it's properly maintained regularly.

Water and Energy Savings Using Demand Hot Water Recirculating Systems in Residential Homes: A Case Study of Five Homes in Palo Alto, California. U.S. Department of Energy.

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A hot water recirculating system costs between $200 and $400, depending on the material used in the construction of the system. For example, a stainless steel system runs about $200, while a bronze or cast iron system can cost $400 or more.

If you have a dedicated return line, then this is a great system to use. You can even get pumps that have timers built in, so the pump only runs during the hours you need it, offering you savings on energy costs.

In a traditional hot water recirculating system, there is a dedicated return line for the hot water pipes, which runs from the furthest bathroom or fixture back to the water heater. Near the water heater area, a recirculating pump pulls the water from the furthest fixture back into the water heater, creating a loop. This loop keeps hot water going throughout the house, so when a fixture is used, hot water is right there.

This recirculating system does not require a dedicated hot water return loop. It can be installed and used in any house. Instant hot water systems come in many different varieties. The two main pump locations are over the water heater and under the sink.

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This style is installed underneath the sink, furthest away from the water heater, and it pushes the hot water into the cold line so you will have hot water for all your fixtures, as needed.

This type of recirculating system is similar to the instant recirculating system, but rather than running constantly or at preset timed intervals; it requires the user to activate the pump when hot water is needed. It can be a traditional style with the pump at the water heater with a dedicated return line, or it can be an under-the-sink pump that is installed in the farthest sink and provides hot water throughout the house.

There are many options for hot water recirculating systems; this guide can help you understand the different types and if this system is right for you.

Aaron Stickley is a licensed plumber with 15 years of experience in commercial, new residential plumbing, and residential service and repair. He started his own residential service and repair plumbing business. Aaron's articles about plumbing on The Spruce span four years.

One study in Palo Alto, California, using a small sampling size of five homes, found that thousands of gallons of water are wasted per year just waiting for hot water to reach the faucet, equalling savings of several hundred to several thousand dollars annually.

An instant hot water recirculating system usually comes with everything you need to install it. You will need power near the water heater to plug in the pump. These systems are recommended for all types of pipes and are virtually maintenance-free.

This loop can run constantly or be used with a timer that may be built into the unit. With the timer, set the pump to run during the times you need quick hot water. Connecting the recirculating system check valve to the system under the sink furthest away allows the system to provide quick hot water throughout the line because the hot water is circulating throughout the house.

A hot water recirculating system is a way to bring hot water directly to the faucet when needed, and if it goes unused, it gets returned to the hot water heater.

This is a very efficient system because when the hot water is sensed at the pump, it automatically shuts off and stops pushing the water from the hot line into the cold side. Pressing a button may give the impression that you still have to wait for hot water, but it can be activated by a wireless remote or with buttons in multiple locations throughout the house, making it very convenient.