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Circulation Pumps: Why You Need One


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When a water heater circulation pump is installed, hot water will be delivered nearly instantly each time a hot water tap is opened. This happens because the pump keeps the hot water moving throughout the plumbing system so that hot water is always available.

In homes without a circulation pump, the hot water tap will run cool water until the hot water from the water heater eventually reaches the faucet. Over the course of a year, hundreds and even thousands of gallons of water can be wasted while waiting for hot water. This can result in not only wasted time and water but also money!

What Does a Circulation Pump Do?

If your home doesn't have a circulation pump, when a faucet is closed the hot water stays within the pipes and eventually cools. When the faucet is then opened again, the cold water needs to be pushed through the plumbing system. The water flow is not hot until the cold water within the pipes is replaced by hot water from the water heater. The result is a lot of wasted water going down the drain!

A hot water circulation pump, also known as a recirculation pump, solves this problem. These pumps circulate hot water throughout your house on a continuous basis, keeping the water within your pipes always hot and ready to be used. When a hot water tap is opened, hot water is delivered right away. However, as good as this sounds, there are some things you should consider before installing a circulation pump to your water heater.

Advantages of Installing a Circulation Pump

Hot water circulation pumps have been around for years. Many high-end hotels and restaurants have provided on-demand hot water to their guests as a standard convenience. However, recently more homeowners are beginning to take advantage of the many benefits a circulation pump can provide.

Here are a few of the advantages:

Convenience: A circulation pump delivers hot water almost immediately when the faucet is opened. The ability to have access to nearly instantaneous hot water is probably the number one advantage.

Water Usage: Because hot water is delivered nearly immediately, less water is wasted. When installed, the need for waiting for the water flow to reach your desired temperature is eliminated. This is particularly useful in areas where water is in short supply. A huge benefit of using a circulation pump is it's ability to save a significant amount of water, resulting in a savings of money and time.

Ease of Installation: Installing a circulation pump is relatively easy and you'll likely already have the tools you need. The majority of pump models are designed for the average home plumbing system. In addition, no special permits are required to add a pump to your water heater.

Ease of Operation: As a general rule, circulating pumps are very straightforward and easy to operate.

Selection: Water heater circulation pumps can be found nearly everywhere with a variety of manufacturers and options to choose between. 

Disadvantages of Installing a Circulating Pump

The convenience of near-instant hot water has a price, but even so, there really are very few disadvantages to installing a circulating pump.

Initial Cost: There's a wide price range to select from, but it's a good idea to purchase a high-end model. Purchasing a quality pump will help you maximize your savings down the road.

Power Consumption: Many of the earlier circulating pumps worked non-stop and were more expensive to operate because they were constantly using electricity. In addition, they also required your water heater to work harder in order to keep the water hot around the clock. Fortunately, many of the current models are made with energy conservation in mind and are designed to deliver hot water on-demand, rather than running all of the time.

Heat Loss: Since your plumbing will be filled with hot water constantly, you'll experience heat loss from the pipes themselves. However, by insulating your hot water pipes you can keep the heat loss to a minimum.

BOKYWOX 110-120V 3/4'',3-Speed Food Grade Domestic Circulation Pump Hot Water Circulator Circulating Pump (RS15-6SG)

Bokywox manufacturers a circulation pump that is priced for nearly every budget.

Types of Circulation Pumps

The simplest system (not covered here) utilizes a small pump that runs continuously. It circulates the water slowly through the home's main water lines (trunk lines) and returns the water back to the water heater if not used. We do not recommend this type of system because it places unnecessary wear-and-tear on the water heater because the system is constantly running.

There are 2 main types of circulation pumps we recommend for your water heater. Both are very energy efficient and effective.

On-Demand Circulation Pumps

These systems are designed so that the pump operates only when there's a demand for hot water, such as opening a faucet or drawing a bath. They're equipped with either a remote switch or a motion detector that triggers the pump to switch ON when movement is detected in the hot water line.

Once activated, the water circulates until it reaches the designated temperature; or the pump is manually switched off; or the timer has expired. Depending on the size of your house, these units typically cost between $300 - $600.


  • If correctly configured, an On-Demand Circulation Pump can reduce the amount of energy your water heater uses.
  • Hot water is delivered rapidly when needed. This will significantly reduce the wasted water and the time you wait for the faucet to deliver hot water.
  • On homes that have retrofitted their plumbing system with an On Demand Circulation Pump, there will be reduced crossover of hot water into the cold water pipes.
  • The ability to override the motion detector and manually activate the pump.


  • On retrofitted plumbing systems it will be necessary to have a power source and a pump at each hot water loop.
  • Hot water is delivered quickly, but not instantaneous because the pump will need to be activated.
  • The amount of time it takes to deliver hot water depends on your home's plumbing configuration.

Time and Temperature Circulation Pumps

This type of system automatically pumps hot water into a supply loop at a designated time. The pump is manufactured with an adjustable timer and an adjustable aquastat which controls the water temperature and also cycles the pump on and off. These units typically cost around $300.


  • The ability to override the settings if you choose.
  • Hot water is delivered nearly instantly which greatly reduces wasted water and time.
  • The settings can easily be adjusted to meet your household hot water needs.
  • Hot water circulates through your plumbing only when both the temperature and time settings are met.


  • If the system is overused it could negatively impact your energy usage.
  • Although not common, if you retrofitted your plumbing with this type of pump, there's the possibility that the cold water lines could be heated at the faucet farthest from the water heater.
NEW 2019 model replaces Grundfos 595916 with 99452459 UP15-10SU7P/LC Instant Hot Water Comfort Recirculation System 9H with NEW Digital Timer

This circulation pump manufactured by Grundfos even has a battery back-up in the event there's a power outage.

Retrofitting Your Plumbing with a Circulation Pump

When a home is constructed with a circulation pump it is plumbed with a dedicated return line which circulates the hot water back to the water heater. Even if don't have the luxury of a dedicated return line, there's an easy way to retrofit your plumbing that'll allow you to install a pump on an existing house using the Time and Temperature Circulation Pump.

A crossover valve is typically installed below the sink that is the furthest distance from the water heater. When the circulation pump is running, hot water will run through the trunk lines of your plumbing. The crossover valve is temperature-actuated and will open when the water in the hot water line falls below 95° Fahrenheit.

Once the valve opens, it'll allow the "cooling hot water" to flow into the cold water line. As the "cooling hot water" is directed into the cold water line, the temperature in the hot water line will rise until a set temperature is reached (usually around 105° Fahrenheit). Once the water reaches the designated temperature, the crossover valve will close.

Watch the Video

It's worth noting that when the crossover valve is open and allowing warm water to run into the cold water line, the cold water may be warmer than expected. Particularly when the circulation pump is running.

The convenience of the Time and Temperature system is hard to deny, however, an On-Demand system has many advantages when retrofitting your home. In fact, it may be slightly easier to install and if used properly, can be extremely energy efficient.

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