You've done the maths on long showers and worked out that flow rate alone won't fix it. The question now is narrower: which smart shower timer actually holds up across a rental portfolio, and does the return justify the spend? Here's a straight answer, with the numbers.
A consumer shower gadget and a portfolio-grade device are not the same purchase. For a rental you're not optimising one bathroom. You're deploying across many, for tenants who didn't buy it and don't pay the bill. That raises the bar to five things: DIY install with no plumber, a nudge tenants accept, per-unit data, payback under a year, and independent validation. We unpack those in the device comparison guide; this piece measures ShowerStar against them.
The core idea is behavioural. Long showers are a habit, and habits respond to cues in the moment, not to a bill 30 days later, which is why real-time feedback devices consistently cut shower use where signage doesn't (Tools of Change).
What you'll learn in this guide:
Key takeaway
For a bills-included rental, the right smart shower timer pays for itself in months by shortening showers automatically, and gives you the per-unit data to prove it.
ShowerStar is a DIY retrofit sensor that fits standard pipes in about two minutes, no plumber, no tools. It auto-detects water flow and starts a traffic-light nudge: green as the shower begins, amber as it runs on, red at the target time. There are no buttons to press and nothing for the tenant to remember.
Behind it sits the TouchGrid app, which configures the device and logs each shower, calculating water, energy and dollar savings using an independently validated methodology. That gives you the one thing signage and manual timers never provide: proof, per unit, per shower. It's the same feedback principle the research backs, a cue you see mid-shower, delivered in a form tenants accept rather than resent.
For a landlord, that data view is the difference-maker. You can see shower duration, water, energy and dollar savings per unit and per person, export it for reporting, and spot which bathrooms are trending the wrong way, all without setting foot on site. It turns a behavioural nudge into a manageable, auditable line in your operating numbers.
Auto-on, nudge, track, and pay back in under a year
Auto-on
Detects water flow and starts automatically
Nudge
Traffic-light cue to wrap up
Track
Logs water, energy and dollars per unit
Validated savings AUD $300-$785 per household per year; payback under 12 months in bills-included rentals.
The reason a coloured light changes behaviour where a bill does not comes down to timing. A utility bill is abstract, delayed and shared, so it exerts almost no pull on the person mid-shower. A cue you can see in the moment is immediate, personal and impossible to ignore, which is exactly the condition under which people adjust. Green, amber, red maps onto something everyone already understands without instruction: keep going, wrap up soon, time is up.
It also makes an invisible cost visible. Water and energy use are normally hidden until a bill arrives, long after the behaviour that caused them. By surfacing the cost of the shower while it is happening, the device closes the gap between action and consequence, which is one of the most reliable ways to shift a habit.
Crucially, the nudge is non-judgemental. It informs rather than scolds, which is what keeps tenants onside and the effect durable. That design is why real-time feedback devices report 20 to 30% reductions in shower use while signage and information alone fall flat (Nature, 2025; Tools of Change). ShowerStar's version was built and validated by an Emeritus Professor at the University of South Australia, so the four-minute target and the savings model rest on evidence rather than a round number that sounded good.
The economics are simple because the saving is per shower, every day. Reducing a 10-minute shower to around 4 minutes saves roughly $0.75 to $0.85 per shower on current Sydney water and NSW energy tariffs (Sydney Water; Electricity Provider). Here's how that scales.
| Occupied bathrooms | Showers / day | Est. annual saving |
| 1 unit | 3 | ~$820 |
| 5 units | 15 | ~$4,100 |
| 10 units | 30 | ~$8,200 |
| 20 units | 60 | ~$16,400 |
Sources: Sydney Water 2026-27, Electricity Provider (NSW gas). Illustrative, ~$0.75/shower saved reducing 10-min to 4-min; higher on electric hot water or in high-frequency housing.
Two factors move that number up. First, hot water type: electric storage systems cost more per minute to heat than gas, so the per-shower saving is closer to $0.85, and the annual figure rises accordingly. Second, shower frequency: student and co-living tenants often shower more than once a day, which lifts a 20-bathroom result well beyond $16,400. Against a device cost of roughly AUD $69, a single occupied bathroom typically returns its cost in well under a year, and the saving compounds as tariffs rise. Sydney Water alone lifted its drinking-water usage charge from $3.17 to $3.41 per kilolitre in a single year (Sydney Water).
There is a softer return as well. A property marketed as low-cost-to-run and sustainability-minded is easier to let and easier to hold, and shorter showers mean less pressure on hot water systems and lower maintenance risk over time. Neither shows up in the per-shower table, but both matter to an operator thinking about the full cost of ownership.
Run your own portfolio numbers with your tariffs and unit count.
Open the Shower Savings Calculator| Feature | Basic timer | ShowerStar |
| Starts automatically | No | Yes, flow-detected |
| Real-time nudge | No | Traffic-light cue |
| Per-shower data | No | Yes, in the app |
| Install | Varies | 2-min DIY, no plumber |
| Independently validated | No | Yes |
Behavioural feedback devices show ~20 to 22% energy and ~10 to 15% water savings in field trials: Tools of Change (Amphiro).
"Our teens went from 20 to 30 minute showers to mostly 4 minutes. The change was surprisingly easy."
Katherine S, ShowerStar customer"Installed in about a minute. We've seen shower times reduce by more than half."
Andre B, ShowerStar customerEvery operator asks the same handful of questions before rolling anything out across occupied units. Here are the honest answers.
"Won't tenants push back?"
A traffic-light nudge is a prompt, not a shut-off or a surveillance feed. It reads as helpful, and interactive feedback is the approach the evidence supports over rules or signage (Nature, 2025).
"I have limited access to the plumbing."
None needed. ShowerStar clips onto a standard pipe in about two minutes with no tools, so a property manager or the tenant can fit it without a trades visit.
"Is it going to need constant maintenance?"
It runs on a rechargeable battery that lasts months between charges, so there is no wiring and no ongoing service call per unit.
"What about the numbers being real?"
Savings are logged per unit in the app on an independently validated methodology, so you are reporting measured data, not a marketing estimate.
"What if a tenant unplugs or ignores it?"
The device sits on the shower fitting and works passively, so there is nothing to switch off, and the nudge is visible whether or not a tenant engages with it. Because it logs data per unit, you can see which bathrooms are performing and follow up only where needed.
Start with a sample
Fit ShowerStar in a handful of units, a representative 10 to 20% of your bathrooms. Each install takes about two minutes, and a quick note to tenants framing it as a cost-of-living and sustainability measure smooths adoption.
Track for 60 to 90 days
Let the app log shower duration and savings per unit, and watch how tenants respond to the nudge. A full billing cycle or two gives you a clean before-and-after.
Validate the numbers
Compare measured savings against your utility bills. This is your evidence base for a wider rollout and for ESG or NABERS reporting.
Roll out with confidence
Scale across the portfolio once the pilot confirms the payback. The per-unit data travels straight into your reporting and your next budget.
The mistake to avoid
Rolling out with no measurement. Without per-unit data you can't prove savings to yourself, your tenants or an ESG assessor, and you lose the strongest argument for scaling. Pilot, measure, then commit.
Yes, and for a portfolio decision that matters. ShowerStar's savings methodology was developed and reviewed by an Emeritus Professor at the University of South Australia, and the product holds a Smart Drop Certified Excellence Award (read the award announcement). That independent grounding is what separates a measured behavioural device from a marketing claim.
It is also why the approach underpins TouchGrid's work with water and energy utilities running efficiency programs, where savings have to be verifiable to count. For a landlord, the same rigour means the numbers you present to a lender, an assessor or a co-owner will stand up.
Prioritise automatic operation, a tenant-friendly nudge, per-unit data and DIY install. ShowerStar meets all four and adds independent validation, cutting the average shower by 3.2 minutes. See how it stacks up against alternatives in our device comparison.
The device is around AUD $69. In a bills-included rental saving roughly $0.75 to $0.85 per shower, a single occupied bathroom usually pays that back in well under a year. Model your figure with the Shower Savings Calculator.
No. ShowerStar is a DIY retrofit that clips onto standard pipes in about two minutes with no tools, so you can fit a whole portfolio without booking trades per unit.
It runs on a rechargeable battery that lasts months between charges, with no wiring and no per-unit service call, which keeps the running cost near zero across a portfolio.
A traffic-light nudge reads as a gentle prompt rather than surveillance, so acceptance is high. Behaviourally designed feedback consistently outperforms rules and signage, which tenants tend to ignore or resent (Nature, 2025).
Yes. The app logs water and energy savings per unit, giving exportable evidence for cost reporting and for NABERS energy and water ratings. Start by understanding how much water and energy showers really use.
It fits standard shower pipes and works alongside gas, electric or solar hot water, since it targets shower duration rather than the heating system. That makes it straightforward to standardise across a mixed portfolio.
The rechargeable battery lasts several months between charges, so there is no wiring and minimal upkeep across many units. You recharge it occasionally rather than servicing it per bathroom.
Pilot ShowerStar across your properties
Fit a sample of units, track savings per unit for 60 to 90 days, and see the payback before you scale. Two-minute DIY install, validated savings of AUD $300 to $785 a year per household.
Request a portfolio pilot