Hot water recirculation pump: what it does and when it is worth fitting
A recirculation pump trades a long wait at the tap for extra heat loss and power use. Whether that is a good trade depends on your pipe run.
A hot water recirculation pump keeps hot water moving through your pipes so it is already warm when you open a tap. It cuts the wait. It does not cut your bills, and in most homes it raises them.
Most houses do not need one. The ones that do share a pattern: a long pipe run between the hot water system and the furthest bathroom or kitchen.
How does a recirculation pump work?
Without a pump, the water sitting in the pipe cools between uses. You run the tap until the cold slug clears and hot water arrives. With a pump, hot water circulates in a loop and returns to the system, so the pipe stays warm.
Some pumps run all the time. Others run on a timer, on a temperature sensor, or when you press a button.
Is a recirculation pump worth it?
Only if the wait is a real problem. Warm pipes lose heat to the walls and the roof space, and the system has to reheat that water. A pump that runs all day pays for that loss every hour.
A timer or an on-demand button cuts the loss a lot. A pump that runs all day, in a house where you shower at two fixed times, is hard to justify. We print no running costs because they vary by tariff and by state.
| Option | What it does | Trade-off |
|---|---|---|
| Continuous pump | Keeps the loop hot all day | Fastest hot water, most heat loss. |
| Timer pump | Runs at set times | Good if your routine is regular. |
| On-demand pump | Runs when you press a button or a sensor triggers | Least waste, a short wait remains. |
What are the cheaper alternatives?
Move the hot water system closer to where you use most hot water, if you are replacing it anyway. Insulate the hot pipes. Our guide to insulating your hot water system covers the tank and the pipes.
Fit a low flow shower head so the wait wastes less water. Catch the cold slug in a bucket for the garden if you want to cut the waste.
What does the installation involve?
A return line, or a bypass valve fitted at the furthest tap, plus a pump wired to power. It touches your plumbing and your electrical wiring, so you need a licensed plumber and, for the wiring, a licensed electrician.
Ask whether the maker of your system allows a recirculation loop at all. Some warranties do not cover one. Read our relief valve guide before you agree to anything that changes pressure in the loop.
How do you know if your wait is too long?
Time it. Open the tap furthest from the system, start a timer and stop it when the water runs hot. A wait of under a minute is normal in most houses and is not worth fixing with a pump.
Long waits come from long runs of wide pipe, because wide pipes hold more cold water. If your wait is several minutes, the pipe layout is the cause. And a plumber can tell you whether a loop, a smaller pipe or a relocated system is the sensible fix.
Will a pump make noise?
Most run quietly, but a pump close to a bedroom wall can hum. Ask for the pump to be sited away from sleeping areas and check whether it can run on a timer so it sleeps when you do.
This far you can go yourself
You can time how long your tap takes to run hot, measure the distance to the system and ask for quotes. You can also fit ordinary pipe lagging to accessible hot pipes where it is simple and safe.
The pump, the return line and the wiring are for licensed trades.
Frequently asked questions
What does a hot water recirculation pump do?
It circulates hot water through your pipes so it is already warm when you open a tap. This cuts the wait for hot water but increases heat loss and power use.
Does a recirculation pump save money?
Usually not. The pump uses power and warm pipes lose heat that the system must replace. It can save water that would otherwise run to waste while you wait.
Can I install a recirculation pump myself?
No. It involves hot water pipework and electrical wiring, both licensed work in every Australian state and territory. Use a licensed plumber and a licensed electrician.
What are the alternatives to a recirculation pump?
Insulate the hot pipes, place the hot water system closer to the taps you use most, and fit a low flow shower head. A timer or on-demand pump wastes less than one that runs all day.
Sources
What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.
- Australian Government, energy.gov.au. Hot water systems — types, installation and energy performance
- Australian Building Codes Board. National Construction Code — Volume Three (Plumbing Code of Australia)