Hot water system electrical work
Off-peak circuits, element and thermostat faults, and heat pump changeovers — the electrical side of hot water.
What's ours and what's the plumber's
Hot water sits across two trades and it's worth knowing the line.
Ours: the circuit feeding the unit, the isolation switch, off-peak and controlled-load wiring, elements and thermostats on electric storage units, and the circuit changes a heat pump conversion needs.
The plumber's: the tank itself, water connections, tempering valve, relief valve and drainage.
For a straight like-for-like electric storage replacement, both trades are usually involved — plumber for the tank, us for the connection. For a fault where you have no hot water, it's worth diagnosing which side it's on before calling anyone, because "no hot water" is about equally likely to be a failed element as a plumbing problem.
No hot water — where to start
No hot water at all, suddenly
On an electric storage system, most often a failed element or thermostat, or the off-peak circuit has tripped. Check whether the circuit breaker for hot water has tripped before assuming the tank has failed.
Call 0422 253 379Hot water runs out much faster than it used to
On a dual-element tank, commonly the lower element has failed and only the top of the tank is heating. The system half-works, which is why it takes people a while to notice.
Call 0422 253 379Hot water only in the evening, or not until late
That's off-peak working as designed — controlled load tariffs heat overnight. If your usage has changed, a boost or a tariff change may suit better.
Call 0422 253 379The circuit trips whenever hot water comes on
Usually an element that has failed to earth. The RCD is doing exactly its job. Don't keep resetting it.
Call 0422 253 379Water is scalding hot or wildly inconsistent
A thermostat fault, or a tempering valve problem on the plumbing side. Worth diagnosing rather than adjusting.
Turn it off at the board and call 0422 253 379Heat pump changeovers
Heat pump hot water is growing quickly, and there are rebates available that make the sums considerably more attractive than they used to be. From an electrical point of view, a changeover from conventional electric storage isn't a like-for-like swap.
A heat pump draws far less power but runs for much longer, and it usually wants to run during the day — particularly if you have solar and want to heat water with your own generation rather than exporting it. That often means moving off a controlled-load off-peak circuit onto a normal circuit, which is a metering and wiring change rather than just a new cable.
Getting that decision right is most of the value. A heat pump left on an overnight controlled-load tariff while you export solar all day is a missed opportunity, and it's a common one.
What hot water electrical work costs
Sydney, 2026. Electrical work only — the unit and plumbing are separate.
| The job | Price |
|---|---|
| Diagnose a hot water faultElement and thermostat testing, circuit check | $180 – $350 |
| Replace an element or thermostatWhere the tank itself is sound | $250 – $500 |
| Connect a replacement electric storage unitTo an existing suitable circuit | $200 – $450 |
| New circuit for a hot water systemWhere none exists or the existing is unsuitable | $450 – $900 |
| Heat pump changeover — circuit and tariff changeMoving off controlled load to a daytime circuit | $500 – $1,200 |
| Off-peak / controlled load rewiringMetering changes involve your retailer | ask |
These are indicative market ranges for Sydney in 2026, not a quote. What you pay depends on your switchboard, access and what we find. We confirm a fixed price before starting, and it doesn't move.
Hot water questions
I have no hot water. Is it electrical or plumbing?
On an electric storage system it's about equally likely to be either. Check first whether the hot water circuit breaker has tripped. If it has, and it trips again on reset, that's an electrical fault — most often an element failed to earth. If the breaker is fine, it may still be a failed element, or a plumbing issue.
Why does my hot water run out so quickly now?
On a dual-element tank, usually the lower element has failed. Only the top portion of the tank heats, so you get some hot water but far less than you used to.
Is a heat pump worth it?
For most households, yes on running cost, particularly with rebates and especially if you have solar and can run it during the day. The electrical change isn't trivial though — it often means moving off a controlled-load circuit, so factor that in.
What is a controlled load or off-peak circuit?
A separately metered circuit that only energises during off-peak periods, at a cheaper rate. Traditional electric storage systems run on it and heat overnight. It's a good arrangement for storage and often the wrong one for a heat pump.
Can I switch my hot water from off-peak to normal supply?
Yes, but it involves your electricity retailer as well as wiring, because it's a metering change. Worth doing when converting to a heat pump; rarely worth doing otherwise.
Do you supply hot water units?
We do the electrical side. Tank supply and plumbing is a plumber's work, and we're happy to coordinate so you're not managing two trades yourself.
What customers say
Jason was great! One call and less than an hour later, he was here to save the day. Five stars for the prompt and reliable service.
Fantastic service! Friendly, efficient and well priced. Highly recommend. Thank you for swiftly fixing our switches.
Jason onsite quickly and completed the work on the spot, giving us a good price and was very polite. Would highly recommend.
These are Google reviews for our team at Cync Electrical & Automation — the licensed contractor behind Hills Electrician. 5.0 from 20 reviews. — see the profile
No hot water?
Check whether the hot water breaker has tripped, then call 0422 253 379 and tell us what you found.
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