A quote you can compare shows five things: the unit, the labour, the tempering valve, removal of the old tank, and any rebate on its own line. If those are rolled into one figure, you cannot tell a good price from a thin one.
Hot water almost always gets replaced in a hurry. The tank goes on a Tuesday, someone is showering at a neighbour's place by Wednesday, and the first plumber who can come out gets the job. That urgency is exactly why quotes for this work are so often one line long.
The unit is not the job
The most common confusion is between what a system costs to buy and what it costs to have working. A heat pump unit on its own runs $2,800–$5,200↗. Installed, the same type of system runs $3,000–$5,200↗. Electric storage shows the same gap.
Installer-reported ranges for Australia in 2026, before any state rebate. Each figure is sourced below.
Show these figures as a table
| Item | From | To |
|---|---|---|
| Heat pump, unit only | $2,800 | $5,200 |
| Heat pump, installed | $3,000 | $5,200 |
| Electric, unit only | $550 | $2,100 |
| Electric, installed | $800 | $2,500 |
When two quotes look far apart, this is usually why. One is quoting the box, the other is quoting the box plus a licensed plumber, brackets, valves, fittings, and a trip to the tip.
Labour: ask for the rate and the hours
Plumbers charge $80–$120 per hour↗ for this work, and a straightforward like-for-like swap takes 2–4 hours↗. Those two numbers multiplied together are a sanity check, not a price. A tank in a roof space, a narrow side path, or a switch from gas to electric all push the hours up, and the gas-to-electric case often brings an electrician along as well.
The tempering valve line
New heated water plumbing has to deliver no more than 50 °C↗ to bathroom fixtures, so a tempering valve is part of the work, not an optional extra. A quote that does not mention it is either assuming the existing valve is fine or has not looked. Ask which. The rule is explained here.
Removal and disposal
Someone has to take the old tank away, and a full one is heavy. Reputable quotes include removal and disposal. It is a small line, but it is the one that turns into an argument on the day if nobody wrote it down.
Where the rebate should appear
Federal small-scale technology certificates are already in your price: Your installer's quoted price already includes the federal STC discount↗. State programs differ. In NSW the Energy Savings Scheme comes to you as an upfront discount↗, so it should be visible as its own line rather than folded silently into the total. In Victoria two separate reductions apply in a set order, which is worth seeing worked through.
If a quote shows a big discount but no scheme name, ask which program it comes from. The answer tells you whether it is a real incentive or just a sale price.
Four questions that sort out most quotes
- Is this price supply and install, or supply only?
- What brand, model and capacity, and is it on the approved list for the rebate you are claiming?
- Does it include a tempering valve, removal of the old unit, and any electrical work?
- Which rebate is in this price, and what is the figure before it comes off?
Prices here are ranges reported by industry guides, not fixed quotes. They are useful for spotting an outlier, not for predicting your own job. Check the source and date under each figure.