If you receive potable hot water instantly after opening a tap, it means that a hot water recirculation system is installed in your house. Let's take a closer look.

Using a return pipe and a special pump, the hot water recirculation system circulates hot water between the pipework and the water heater, maintaining the water temperature when all taps are closed.

In a house without a hot water recirculation system, the freshly heated water… will eventually cool down if it has not been used for a while. The next time a resident needs hot water, they will have to wait until all the cooled water is poured out and replaced with the new, freshly heated water.
Typically, in a single-family house, it can take up to two minutes to wait for hot water. That’s up to 10,000 gallons or 37,850 litres wasted annually.
Stagnating warm water also raises hygiene concerns. Legionella bacteria are known to thrive in such conditions… and the periodical circulation of high-temperature water is a comprehensive way to prevent this from happening.

This is why many countries have established regulations mandating buildings to have hot water recirculation systems… as it solves these problems.
For hot water recirculation to work correctly, the system needs the right pump. The COMFORT pumps developed by Grundfos feature everything needed to ensure safe, reliable, and energy-efficient circulation, and are approved for drinking water. The parts in contact with water are made of corrosion-resistant materials such as brass and stainless steel to protect the potable water from chemical reactions.
The pumps work silently thanks to the permanent magnet motor and the unique “shaftless” design of the rotor. This also enables the ability to operate in water of any hardness. The hydraulic performance of the COMFORT pumps is tailored for private homes and will ensure hot water is available at any time, while consuming no more than 7W.

To minimise both the electrical energy and heat energy consumption of your water heater, the COMFORT pumps have four smart control modes for optimising operating time without sacrificing resident comfort.

The COMFORT pump can work constantly, 24 hours a day, 7 days a week, but it would make the water heater spend the maximum amount of energy resources to maintain the highest temperature in the loop at all times. The temperature control mode of COMFORT T will reduce energy losses, turning on the circulation only when the water temperature in the loop falls below a certain value. It may reduce energy resources by around 25%. The combined timer and temperature control mode of COMFORT TDT may reduce heat energy losses even further by eliminating hot water circulation in periods when there is no need for it, such as at night or when the house occupants are at work.

The highest reduction in heat energy can be provided by the AUTOADAPT control mode of COMFORT TA. The pump quickly learns usage patterns throughout the day, differentiating between mornings, evenings, and periods of inactivity such as vacations. On average, it may reduce heat losses by around 67% in comparison with constant circulation.

Let’s sum up the benefits - the COMFORT hot water recirculation pumps help to:
Save up to 2 minutes when waiting for hot water
Save up to 10,000 gallons or 37,850 litres of water annually
And prevent rust and Legionella growth in the water… while minimising energy consumption.