How Does On-Demand Recirculation Work?

Most conventional recirculation pumps run for hours during the day, even at times when nobody is using hot water. When this happens, energy is lost and your water heater must continue to fire up and reheat unused water, resulting in high gas/electricity use. On-demand recirculation systems, such as AutoHot, only operate when two conditions are met:

There is a demand for hot water (as detected by a sensor or switch)
There is no hot water presently in the line (as detected by a temperature sensor)

In other words, when there is no hot water demand, such as when you’re at work, on vacation, sleeping, or just hanging around the house, the system stays off. When hot water is in the line, such as when it’s coming out of the faucet, or just recently used, the system stays off, even if it continues to sense demand. Operating in this manner usually results in pump run time of less than 15 minutes per day total, and can achieve upwards of 10,000 gallons of water savings per year at a cost of less than $2.00 in energy to operate the system. Compare this with timer/temperature based systems that sees hours of run time per day, needlessly running and turning on your water heater

AutoHot works in any plumbing system, whether you have a dedicate return line or just standard plumbing, and works with any tank, tankless, or heat pump water heater.

Download Documents

Go to Shop

How to Order

For Standard Plumbing Systems,

Under Sink Kit Available

For Plumbing with Dedicated Return Lines

Product selection

Determining the correct AutoHot® System for your home is simple. AutoHot® system is easily configurable to match any situation. Follow the steps below, and if you need help, don’t hesitate to contact us.

choose the right system in 3 simple steps



Determine Ideal Pump Size



Identify Install Location



Select Activation Options

Product selection

Determining the correct AutoHot® System for your home is simple. AutoHot® system is easily configurable to match any situation. Follow the steps below, and if you need help, don’t hesitate to contact us.

choose the right system in 3 simple steps

Determine Ideal Pump size

Identify Install Location

Select Activation Options

Determine ideal pump size

Multiple Pump Sizes Available

The pump size will affect the speed at which the water moves through the pipes. The larger the house or the more lineal feet of piping, the bigger the pump size you would want to be able to get hot water throughout the house quickly.

55 Series Pump – Most common size, fits on most homes that are 2200sq ft or smaller, or if you have tankless water heater and less than 150 lineal feet between the heater and the furthest fixture
99 Series Pump – For larger homes, or when you have a tankless system with more than 150 lineal feet of pipe between the heater and the furthest fixture.
150 Series Pump – Oversized pump used for special applications, contact us for suitability.

identify install location

Retrofit into any home

Are you installing your AutoHot® System on a return line or under the sink at the furthest fixture from the water heater? The install location determines whether you need the “Under Sink Kit (-USK).”

Use a system with “-USK” in the model number if:

You do not have a dedicated return line
Retrofitting a house without an existing circulator pump
You are installing at the end of a “dead-leg” branch line or riser

Do not choose a model number with “-USK” if:

If you have dedicated return line
You are not installing under a sink, but are installing by the water heater
You have an existing circulator pump

select activation options

Wired/Wireless - Button/Motion

Select the way in which you will activate the system when you want hot water delivered throughout the house. The AutoHot® System comes standard with one wired stainless steel button, but you may add additional activators and mix and match different activation styles to suit your needs.

Wired Decora Rocker Switch (White)
Wired Pushbutton (Chrome)
Wired Motion Sensor (Ceiling mount or wall recessed versions)

Wireless Push Button (Up to 1000 ft. range)
Wireless Motion Sensor (Up to 500 ft. range)

AutoHot® Residential On-Demand Recirculation Systems (Base Models)

Part No.	Image	Description
DR000A (Gen 2)		Residential AutoHot demand control (Gen2), no pump
DR055A (Gen 2)		Residential AutoHot, 55 series pump, wired and wireless button activator
DR055A-USK (Gen 2)		Residential AutoHot, 55 series pump, Under Sink Kit, wired and wireless button
DR099A (Gen 2)		Residential AutoHot, 99 series pump, wired and wireless button activator
DR099A-USK (Gen 2)		Residential AutoHot, 99 series pump, Under Sink Kit, wired and wireless button
DR150A (Gen 2)		Residential AutoHot, 150 series pump, wired and wireless button activator
DR150A-USK (Gen 2)		Residential AutoHot, 150 series pump, Under Sink Kit, wired and wireless button

Accessories (for homes, order separately)

Part No.	Image	Description
WR-16A (only needed for Gen 1 controllers)		Wireless receiver (for 1st generation models only)
WB-S-16A		Wireless Button Activator: Works up to 1000 ft away in open air
WM-S-16A		Wireless motion sensor
HR-S-17W		Hardwired rocker switch activator
HB-S-13A		Hardwired push button activator
MBKT-19A		Pump wall mounting bracket, set, for 55, 99, and 150 pump
HR-S-17LED		Hardwired LED lighted rocker switch
HB-S-20LED		Hardwired LED lighted button