Exploring Recirculating Pumps for Water Heaters: Why They are Important?

Do you find yourself waiting for hot water in your home? Whether it’s at the sink or in the shower, waiting for the water to heat up can be frustrating and wasteful.

Luckily, there’s a solution: hot water recirculating pumps. In this article, we’ll discuss how installing one can provide you with hot water faster and why it’s an important upgrade for your plumbing system.

In recent years, recirculating pumps for water heaters have become increasingly popular as homeowners seek to improve their home’s energy efficiency and reduce water waste. These pumps work by circulating hot water through the pipes, so it’s readily available when you turn on the tap, eliminating the need to wait for the water to heat up. This not only provides hot water on demand but also reduces the amount of water wasted while waiting for hot water to arrive.

In this article, we will explore the different types of recirculating pumps, how they work, the benefits of using them, and what factors to consider when choosing the best model.

Recirculating Pumps for Water Heaters: Do I Need One?

Recirculating Pumps for Water Heaters
Grundfos recirculating pump (photo: amazon.com)

Imagine waiting endlessly for hot water to finally make its way to your faucet, shower, or sink. That’s the reality for many homeowners with larger homes that have lengthy plumbing systems connecting their water heater or boiler to the delivery points.

As a result, users are often forced to let some water run down the drain before the warm water is finally delivered, leading to wastage of time, energy, and water, as well as unnecessary expenses.

This can be extremely frustrating since the first few minutes provide mostly uncomfortable showers and an unpleasant overall experience. Therefore, users naturally blame the water heater.

That’s why many homeowners decide to buy a hot water circulation pump and install it in the recirculation loop, shortening the wait time and reducing waste.

Although other options are available, such as installing a water heater booster or a tankless unit with an integrated pump or unit upgrade, the circulating pump seems to be the most efficient and cost-effective solution.

Hot water recirculating pumps are a great solution in domestic water heating systems because they guarantee fast water delivery, warm or hot, from the water heater, plumbing pipes, and fixtures. It can be said that hot water is delivered instantaneously, but it depends on the type of system.

This is done by circulating hot water through the pipes even when the tap is not open and there is no demand for hot water.

These systems are known as recirculation systems. With the installed pump comes a dedicated return line connecting the fixture and water heater. A dedicated return line is recommended due to its independence from the supply line, mainly in new homes, as its installation in an existing one can be expensive.

If the dedicated line is not a viable option, then the existing cold water line combined with the bypass valve can be utilized, where cold water is recycled back to the heater instead of going down the drain.

However, not all hot water circulating pumps are worth the money. Therefore, it’s essential to learn what to look for before buying one.

Types of Recirculating Pumps

The circulating pumps mentioned here belong to a group of centrifugal types, which are the most common type seen in home plumbing and heating. They utilize the mechanical force from a motor and transfer it to an impeller, increasing the water velocity.

In open systems such as water heating systems where fresh water is delivered regularly, cast iron pumps should not be used because when the iron is exposed to oxygen, it rusts quickly. Instead, choose pumps made of stainless steel or bronze.

Several types of circulating pumps are used in water heating systems, including continuous (ON/OFF), on-demand, temperature-controlled, and time-controlled pumps.

Continuous or ON/OFF Pumps

This is the simplest type. It runs non-stop (continuously), which results in additional stress, a shorter lifespan, and unnecessary energy consumption when hot water is not needed.

On-Demand Circulating Pump

On-demand models use either a motion sensor or a manual switch to activate them. When activated, they immediately deliver hot water to the fixture, providing an efficient and convenient solution for those who want to reduce energy consumption and water waste.

Time-Controlled Pumps

This type utilizes a timer to run, but only at the set time or when the demand for hot water is highest, such as during morning or evening routines. This ensures that hot water is readily available when needed, without wasting energy or water during periods of low demand.

Thermostatic Pump

The thermostatic type is a temperature-controlled pump that ensures that water at the desired temperature is always available at the fixture. Once the set temperature is achieved, the device turns off, and turns back on when the temperature drops.

This type can also be combined with a timer for even greater energy efficiency and convenience.

How to Choose a Recirculating Pump

When selecting a recirculating pump for plumbing or water heating, there is a list of features you should consider. Although they may seem simple and straightforward, some features can significantly impact your experience during installation and use. These features include:

Connection Size

When discussing size, we’re not referring to the physical size of the device, but rather the size of the connections. These can range from 1/2 inch to 3/4 inch or more. Knowing the size of the connections is important as it will indicate whether the pump is compatible with your home’s pipe system, and what modifications may be required for installation.


One of the most useful features in hot water circulation pumps is a timer. With a timer, users can set the pump to operate according to their regular water usage routines, making it more convenient and efficient. Many models come equipped with a 24-hour timer, which makes them easy to use and further improves their energy efficiency.

Flow Rate

Recirculating pumps are designed to deliver hot water faster than average, but the flow rate, measured in GPM (gallons per minute), is what determines how quickly the device can do so. Most models provide GPM measures ranging from 0 to 9, but the necessary GPM will ultimately depend on the length of your pipe system. In general, the longer the pipes, the more GPM will be required to achieve fast hot water delivery.


A high-quality water pump can help users save a significant amount of water per year. An efficient model can save anywhere from 12,000 to 30,000 or more gallons, which translates to 30 to 100 gallons per day. The efficiency of the product directly correlates to the amount of water and money saved in the long run.

The features of these pumps will vary depending on the model and type of device. To help you find the right model, here are some interesting options to consider.

Top-Selling Water Circulating Pumps

Grundfos Comfort Series Circulating Pump

With a single-phase 115v motor and a maintenance-free design, the Grundfos provides a fantastic performance when it comes to recirculating water. It comes with stainless steel construction, which makes it much more durable than others. Works with a low-watt connection and can help you save up to 38,000 gallons of water per year.

It also boasts a 24-hour timer which allows users to use it according to their needs. What’s more, it is effortless to install near the water heater in under 2 hours and will help increase the effectiveness of home appliances without problems.

Watts Recirculating Hot Water System with Built-In Time

The 50800 circulating pump model from Watts helps to save up to 15,000 gallons of water per year thanks to its 10% efficiency-wise design. Its installation is entirely straightforward, where a professional can do it in an hour or so. The device comes with a 10 ft. power cord and a 24-hour timer for more convenience.

It only works with tank-type water heaters, yet it provides superior performance than most, thanks to its excellent GPM. It is maintenance-free and includes two additional 12-inches supply lines for productive use.

Laing AutoCirc ACT E1

Designed with an ECM/PM technology, it is highly efficient and easy to use. It’s perfect for recirculation and doesn’t require an additional recirculating pipe to use. It comes with an adjustable 24-hour timer and a 6-foot power cord for easy installation. It can be installed under the sink, far from the water heater.

It works by automatically turning on when the water is 89 F or below, heating it up until it meets 95 F when it automatically turns off again. It goes better with tankless water heaters. It works with only 14 watts and can save up to 17,000 gallons of water a year.

Advantages of Using Recirculating Pumps


Using a recirculation pump immediately provides a boost to hot water efficiency and comfort. No more complaints that it takes too long for hot water to reach the shower. No cold water splashes. Hot water is there almost instantaneously, as soon as you open the tap. They save you time and money.

Water Conservation

Without a circulating pump, water heating systems tend to make users waste water before delivering hot water to the tap. And when installed, spending water inefficiently is a thing of the past.

Easy and Fast Installation & Use

Most recirculating pumps are a lot easier to install than other similar-purpose systems, demanding only an hour or so for the installation. Moreover, most of them work automatically without human interaction. There are no special permits needed for the installation. Once installed, there is no maintenance required.


Waiting for hot water to reach your faucet can be frustrating, but a recirculation pump can provide an efficient solution to this problem. By investing in a high-quality model and having it professionally installed, you can enjoy energy and water savings, as well as increased comfort and convenience. Keep in mind that the best models, such as the one reviewed above, may come at a higher price point, typically a few hundred dollars. However, the long-term benefits make it a worthwhile investment for many homeowners.

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