What has to exist before a savings number goes in an ad

You write “cut your power bill by 70%” into a retrofit ad. Somebody asks where the number came from. What you can put in front of them is the whole question, and the law is specific about it.

This post is about a savings number: a bill reduction, a payback period, a return. Not about whether a battery is a good idea. Two duties apply, they apply at different moments, and most writing on this topic runs them together.

As on the other posts in this cluster: everything with a clause number is NETCC and binds signatories. Everything with a section number, or attributed to the ACCC, reaches you either way. Inside a quoted clause, “we” is the signatory and “you” is the homeowner.

The ad duty and the quote duty are not the same duty

The ad. If you are a NETCC signatory, clause 3(g) requires you to “ensure that any claims relating to performance and energy cost savings of our New Energy Tech are reasonably based and where available, based on reputable sources”. That is the standard for what goes in the ad.

The quote. Clause 15 triggers on something narrower and asks for far more. If the quote claims the customer is likely to achieve a favourable return on investment, the quote must include an ROI calculation “based on reasonable assumptions and where available from reputable sources”, setting out the assumptions behind it.

Clause 15 also closes with a requirement people miss:

We will also clearly state that our calculation is an estimate only and that if our assumptions prove not to be correct you may not achieve the estimated return.

So the estimate statement is not a courtesy or a lawyer’s habit. For a signatory, it is part of the clause.

Clause 13 runs alongside clause 15. The quote “will specify the total value of any discounts, regulatory certificates, incentives or rebates (government and non-government) or government relief schemes and how and when these may or may not apply”.

So an ad can be perfectly compliant and still leave a quote duty unmet, because the quote is written a fortnight later by a different person with a different template. That is the gap this post exists to close.

The Australian Consumer Law sits underneath both and does not care whether you signed anything.

What “reasonably based” means under the statute

A saving, a payback period or a return is a statement about the future. The Australian Consumer Law treats those differently from statements about the present.

Under section 4 of the Australian Consumer Law — Schedule 2 to the Competition and Consumer Act 2010 (Cth) — a representation about a future matter is taken to be misleading if the person who made it does not adduce evidence that they had reasonable grounds for making it. Where that evidence is not put forward, they are taken not to have had reasonable grounds.

Read that slowly, because it is written up wrong more often than it is written up right.

• It does not say you have to prove the claim was true. A forecast that turns out wrong is not, by itself, a breach.
• It does not place a legal onus on you to prove you had reasonable grounds.
• What it does is put an evidentiary burden on you. Evidence has to go on the table. If nothing goes on the table, the claim is treated as misleading without anyone having to demonstrate that it was.

The practical translation is short. The working has to exist at the time you make the claim. Not be assembled afterwards if somebody asks.

Two other things from the ACCC belong next to that. On intent: “It makes no difference whether a business intends to mislead or not.” On evidence: “A business must be able to prove any claim they advertise.” And the mechanism behind the second sentence is a substantiation notice — the ACCC can require a business to produce evidence supporting a claim, and the business has 21 days to respond.

Twenty-one days is not enough time to build a savings model from nothing. That is the whole argument for doing it first.

The assumption list, taken from clause 15

Clause 15 names the categories a quote-stage ROI calculation has to set out its assumptions on. They make a serviceable checklist for any savings number, including one in an ad, even though the clause itself is a quote-stage duty.

Assumption	What “reasonably based” looks like for a battery retrofit
System design and output	The specification of the battery actually being installed — usable capacity, not nominal, since the certificate calculation runs on usable capacity. Not a figure carried over from a different model.
Financial incentives	The certificate rate that applies on the installation date, and the capacity band it applies at. Not last period’s rate, and not a flat rate applied across the whole battery.
Energy prices and usage	The customer’s own bill data, or a stated assumption with its source named. An unnamed “average household” is the weakest link in most savings models.
Financing costs	If there is a finance offer attached, its cost is part of the return and belongs in the working.
Maintenance costs	Whatever the product and your own warranty position actually imply over the period.
End-of-life costs	Named explicitly in the clause. It is the assumption most often left out entirely.

The clause requires the assumptions to be set out, not hidden. A calculation with stated assumptions is defensible even if the outcome disappoints. A number with no assumptions behind it is not defensible at all, and it is also useless to the customer.

Worked example: a bill-reduction number

Take “cut your power bill by 70%.”

To make that reasonably based, something like the following has to already exist, in writing, before it runs:

1. A stated consumption assumption — how much electricity the household uses and when. A battery only pays where load and solar generation are out of step, so the shape of the usage matters as much as the total.
2. A stated tariff assumption, with the retailer and plan named, and the date it was current.
3. The actual usable capacity of the battery being sold, and what proportion of the evening load it covers.
4. A stated self-consumption or cycling assumption, and where it came from.
5. A statement that the figure is an estimate and the customer’s result may differ.

If all five exist, “70%” is a claim with grounds. If two exist, it is a number somebody liked the look of.

There is a shortcut worth naming, because it is the one most often taken: quoting the top of the range and describing it as typical. Clause 3(c) reaches that directly. It prohibits misleading claims about “the price, value, quality, capacity, output or other performance characteristic”, including “through selective advertising, exaggeration or misleading focus on one or a few aspects only”. A number that is true for one customer, presented as what customers get, is exactly that.

Worked example: an incentive number

The rebate figure is the other number in every retrofit ad, and it substantiates differently. The problem there is rarely arithmetic. It is currency and specificity.

Four things have to be true before a rebate figure goes anywhere.

It has to be the rate for the installation date. The Clean Energy Regulator states it directly: “Rebates are determined by the installation date, not when a contract is signed.” A customer signing before a step-down and installing after it lands on the later rate.

It has to account for capacity. The certificate rate is not applied flat across the whole battery. Above a published capacity band it tapers. A per-kWh figure that is correct for a small battery overstates the rebate on a large one, which puts it under clause 3(c) again.

It has to be described as the mechanism it is. The scheme creates small-scale technology certificates against usable capacity. Those certificate rights are assigned to a registered agent and come off the price at the point of sale. “The government pays you” is a description of a different thing that does not happen, and it will not survive a customer reading their own invoice.

A dollar figure has to state what it assumes. The Clean Energy Regulator publishes the certificate rate. It does not publish a dollar-per-kWh rebate. The dollar value is the rate multiplied by what a certificate is worth on the market on the day, less the agent’s margin and costs. Any dollar figure is therefore an assumption about a market price, and it goes stale in a way the certificate rate does not. If you use one, say the price it assumes and the capacity it applies to, in the same sentence — not in a footnote, which clause 3(j) would have something to say about anyway.

That is how we handle it on this site. The rate and the dates it applies from are published on the page about battery retrofit campaigns to an existing customer list, with the source and the date it was last checked, and no dollar rate is printed as though it were a government figure.

When the assumptions turn out wrong

They will, sometimes. A customer changes retailer, works from home, buys an electric car, or has a mild summer.

The protection is not that the forecast was right. It is that the estimate was reasonable when it was made, its assumptions were written down, and it was presented as an estimate. That is what section 4 asks about and what clause 15 asks you to record.

Which means the discipline pays twice. The same document that makes the claim defensible is the document that lets a salesperson explain, a year later, exactly why the number came out where it did.

Where this fits

The advertising side of this — what clause 3 prohibits, and the separate rules for direct marketing — is in what NETCC clause 3 actually prohibits in a battery ad.

Applied to a real database campaign, step by step, it is what a compliant battery retrofit campaign looks like.