Do I need a timer on my pool heater?

The provision, and why it is a building requirement rather than advice

This sits in the energy efficiency part of the National Construction Code, not in the pool safety part, which is why it is so easy to miss when you are researching heating.

VBA Practice Note 05-2018 restates it: BCA Volume One J7.3 and J7.4, and BCA Volume Two Part 3.12.5.7 and 3.12.5.8, specify the energy efficiency requirements for swimming pools and spas. Within those, the practice note quotes the operative sentence: ‘Where the heating is by a gas heater or heat pump, the swimming pool must be provided with a cover and a time switch to control the operation of the heater.’

The quotable version: if your pool is gas or heat pump heated, the cover is not a saving you might make — it is part of the compliance of the installation.

The Code also lists what the heating may be: a solar heater (not boosted by electric resistance heating), a gas heater, a heat pump, a heater using reclaimed energy, or a combination of these. A spa pool sharing a reticulation system with a swimming pool can be heated by one or a combination of the same methods.

Our comparison of solar, gas and heat pump pool heating covers how the three compare on capital and running cost; this page is about what the Code adds on top of that choice.

What it means for your quote and your budget

Two practical consequences, and they point in opposite directions.

The cost consequence. If you are comparing a gas heater against a solar system on installed price alone, the gas option carries a cover with it as a requirement. That is a real line item that belongs in the comparison rather than in a later conversation. Our page on pool cover cost and payback sets out the published price ranges and the payback arithmetic.

The saving consequence. The reason the Code pairs them is that they work together. A cover suppresses evaporative heat loss, which is the dominant loss path on a heated outdoor pool; a time switch stops the heater running when nobody will swim. A requirement that lowers your running cost is an unusual kind of requirement, and this is one.

The spa rule is separate and easy to trip over. A spa pool with a capacity of 680 litres or more must have a time switch on the circulation pump — that is about the pump, not the heater, and it applies regardless of how the spa is heated. Many domestic spas sit near that threshold, so the capacity figure is worth checking on the compliance plate rather than estimating.

If you are pricing the equipment side of a pool, annual pool running costs puts heating in context against pumping, chemicals and water.

Who is responsible for it, and when it is checked

The requirement attaches to the building work, which means it is a matter for the building permit and the relevant building surveyor rather than something you retrofit at leisure.

The practice note is written for building surveyors and is a restatement of NCC provisions, so the enforcement point is the permit and the inspection regime around it. The practical implication: if heating is in the scope of the pool build, the cover and timer belong in the documentation, not on a shopping list for later.

Where heating is added to an existing pool afterwards, the position is less crisp, because whether a building permit is required depends on the work and the state. We could not verify a single national rule for retrofitted heating, so we are not stating one. The safe course is to ask the installer whether the installation requires a permit and, if it does, whether the cover and time switch are in the documented scope.

A related Victorian point worth knowing if you are altering an existing pool at the same time: the VBA material makes clear that where work is undertaken on an existing pool, spa or barrier, the pool, spa or barrier needs to be brought into compliance with current Regulations. Heating work that coincides with barrier work can therefore drag the barrier into scope — see Victorian registration and barrier compliance.

The honest version of the running-cost question

People search for this rule because they want to know whether a timer will save them money, so here is the method rather than a promise.

A heater's running cost is driven by three things you control: how warm you keep the water, how long the heater is permitted to run, and how much heat the pool loses when nobody is in it. A time switch addresses the second. A cover addresses the third. Neither addresses the first, which is usually the largest.

Work it yourself: take the heater's input rating from the compliance plate, multiply by the hours you currently allow it to run, and compare that against the hours a timer would allow. The difference is the ceiling on what a timer can save you — not the saving, the ceiling. Then ask the same question about the set temperature, because a degree of water temperature is a permanent cost in a way that an hour of run time is not.

We do not publish an average saving, because the honest range across household patterns is too wide for an average to be useful, and the figures circulating on vendor pages are not independently verified. What the Code settles is not how much you will save. It is that on a gas or heat pump pool, you do not get to choose whether to have the cover and the timer at all.

If you are still choosing a builder and want the heating scope priced properly, get a quote and ask each builder to show the cover and time switch as named line items.

Common questions

Sources

• VBA Practice Note 05-2018 — Swimming Pool and Spa Safety (council-published copy)
• Australian Building Codes Board — National Construction Code

General information only, current at 2026-09-22. Pool rules differ by state and by council, and penalty amounts are updated regularly. Confirm your own obligations with your council or a registered inspector before acting.