Repaired where a repair is honest, replaced where it is not, and with the question nobody raises until the first bill raised before you order anything.
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A large proportion of the electric storage systems in this housing run on a controlled load, which most people know as off peak. It is a separate supply to that one appliance, switched on at set times, usually overnight, at a lower rate than general usage.
The whole design follows from that. The tank is large because it has to hold enough hot water to get a household through the day on one overnight heating cycle. That is why these units are the size they are, and it is why nobody thinks about them: they simply work in the background.
Change the system and that logic changes with it. A much smaller tank, or something that heats on demand rather than overnight, does not fit the same arrangement, and what the household pays to run hot water moves accordingly. Sometimes down, sometimes up, depending on the household and how it uses water.
We are not arguing against changing systems. We are arguing against discovering this afterwards. It is a five minute conversation before anything is ordered, and it is a genuinely unpleasant surprise in a first quarterly bill. What we will not do is quote you a running cost, because that requires knowing your tariff and we do not.
Ask about the tariff arrangement before the order goes in. It is five minutes and it is not a question anybody selling you a unit tends to raise.
A separate supply runs to the one appliance and is switched on at set times at a lower rate. The tank heats through the night and then coasts through the day on what it stored.
A lot of the housing here runs exactly that arrangement, because it was the sensible way to do electric hot water when these houses were built and it is still cheap to run.
It is worth knowing whether you are on it before you change anything, because it is the single biggest factor in what your hot water actually costs you.
It is large because it has to carry a household through a whole day on one heating cycle. That is the design, not overprovisioning.
So a 250 or 315 litre cylinder on a controlled load tariff is not an oversized tank. It is the right tank for the way it is being heated.
Which is why swapping it for something smaller on the assumption that bigger is wasteful gets people into trouble.
A smaller tank or an on-demand system does not fit the same logic, and moving off controlled load means moving onto your ordinary tariff for water heating.
That can still be the right decision. Continuous flow gas, or a heat pump on a normal supply, both have real arguments in their favour. But the running cost comparison has to include the tariff you are leaving.
Nobody mentions this when they quote a replacement, which is why people are occasionally surprised by the first bill afterwards.
It is on your electricity bill as a separate line with its own usage and its own rate. Two minutes with a bill tells you more about the decision than any amount of general advice.
If the controlled load rate is well below your general usage rate, an old electric tank can be cheaper to run than people assume.
We would rather you made the comparison than take our word for it, because the numbers differ by retailer and they change.
A controlled load tank has a finite amount of hot water and it is not being topped up during the day. Heavy use in the evening runs into the bottom of the cylinder.
Some retailers offer a boost, and some installations have a manual boost switch already fitted, which heats the tank outside the usual window when you need it.
That is worth asking about before concluding the tank has failed. A household that has grown is the most common reason this starts happening.
Sydney water is soft. Cylinders here do not silt up the way they do in hard-water regions, so hard-water advice found online does not describe a tank in this suburb.
What ends a cylinder here is corrosion, and the sacrificial anode exists to corrode instead of the steel. Once it is gone, the tank starts spending itself.
Renewing one costs a fraction of a replacement and buys years. On a tank around six or seven years old it is the best value item on this page.
Run the cold, then the hot. Clear cold with rusty or discoloured hot is the single most informative thing a hot water system will ever tell you, and it means the steel is corroding.
Rumbling as it heats is the other one, usually sediment sitting on the bottom of the cylinder.
Together they mean the unit is near the end of its useful life. Replacing on your own schedule is cheaper and far less disruptive than replacing on its.
Houses here get extended, and a bathroom added at the back is frequently a long way from a unit installed where the original one went. The cold water standing in that run has to be pushed out first.
That is pipe length rather than a failing heater, and no work on the unit shortens it. The honest options are a recirculation line or a small unit at that end.
The exception is a wait that has got noticeably longer than it used to be. A change is a symptom, where a constant is geometry.
A tank in a garage, an internal cupboard or a tight side passage narrows the options. Continuous flow needs an external wall and a flue path. A heat pump needs airflow, clearance and somewhere its noise is acceptable.
None of that rules out changing systems. It means working it out before ordering, because the cheapest unit that will not fit where the old one was is not cheap.
Getting the old one out is part of the job too, and on an internal cupboard that is a real part rather than an afterthought.
Water emerging from the body of the cylinder rather than from a fitting on it. That is the steel, and steel does not get patched.
A leak at a valve or a connection is ordinary work and frequently cheap. Confusing the two costs people a great deal.
Isolate it, cut its power or gas, and book the replacement. Waiting adds flooring and plaster to a bill that was only ever going to be a hot water system.
We will not invent a running cost for you, because that needs your tariff. What we can set out is how each type behaves, which is the part that is the same for everybody.
| Type | When it heats | Expected span | The trade-off |
|---|---|---|---|
| Electric storage on controlled load | Overnight, in one cycle | About 8 to 12 years | Cheap to run per unit, but it must be large enough to last the day |
| Electric storage on general supply | Whenever the thermostat calls | About 8 to 12 years | Recovers any time, at the general usage rate |
| Gas storage | Whenever the thermostat calls | About 8 to 12 years | Faster recovery, and it needs gas and flue clearances |
| Continuous flow | On demand, storing nothing | About 15 to 20 years | Cannot run out, and nothing is kept hot between uses |
| Heat pump | On a cycle, moving ambient warmth into the tank | About 10 to 15 years | Lowest running cost of the electric options, needs airflow |
A starting point rather than a rule. Storage is judged on how much can be drawn before it empties, so the number that counts is how many people want hot water inside one hour.
| Occupants | Electric storage | Gas storage | Continuous flow |
|---|---|---|---|
| One or two | 125 to 160 L | 90 to 135 L | 16 L/min |
| Three to four | 250 to 315 L | 135 to 170 L | 20 L/min |
| Five or more | 315 to 400 L | 170 L or twin | 26 L/min |
| Two bathrooms at once | Size up a step | Size up a step | 26 L/min |
Fixed price agreed before anything starts. These are indicative 2026 ranges.
Taken off the repair in full if you ask us to carry it out.
The most common electric fault, and the reason a cold tank is not automatically a dead one.
Cheap insurance on a cylinder with years left in it.
Unit, install and removal of the old one, in a single figure.
Subject to gas at the property and a wall that meets the flue clearances.
Plenty of large electric storage through this housing, gas where a property is connected for it, and continuous flow wherever a cylinder had to come off the floor. These are the makes behind it.
We service and replace these systems as an independent licensed plumber. We are not an agent for, or endorsed by, any of these manufacturers.
Type, age, and whether the electricity to it is a controlled load. That last answer shapes the whole replacement conversation.
Every unit carries a compliance plate with a date, and we read it out, because a real age turns repair or replace into arithmetic.
Anode, element, thermostat or valve where that genuinely solves it. Nothing gets changed over while it has life left.
We run it, check the delivered temperature, take the old unit away and leave you the paperwork.
A licensed plumber answers directly. Repairs are usually same-day and plenty of changeovers are too.
Call 1300 381 569A controlled load, often called off peak, is a separate electricity supply to a single appliance that is switched on at set times, usually overnight, at a lower rate than general usage. Electric storage hot water is the classic appliance on one. If your tank is large and the water is hot in the morning but you have never thought about when it heats, there is a reasonable chance yours is on one.
Because the arrangement is tied to the appliance. A tank sized to heat overnight assumes it holds enough to get the household through the day. Move to a much smaller unit, or to a system that heats on demand, and that logic no longer applies, and what you pay to run it changes with it. Whether it changes for better or worse depends on the household.
Not at all, and we are not arguing against one. We are arguing against finding out about it afterwards. It is a five minute conversation before the order, and it is a very unpleasant surprise in the first quarterly bill.
Not to the dollar, and anyone who says otherwise is guessing at your tariff. What we can do is tell you plainly how each system behaves, so you can put that against your own bill rather than against somebody's example.
Soft water is why they fail this particular way. In hard-water places a tank silts up with scale. Sydney's supply is not like that, so instead the sacrificial anode is consumed protecting the steel and the tank starts corroding once it is gone, or an element burns out.
Replace. Water from the body of the cylinder means the steel has gone and there is no patch for that. Shut it off and ring, because the damage compounds daily.
Diagnosis is $120 to $250 and comes off the repair. An element or thermostat is $250 to $550. An anode is $300 to $600. A storage replacement is $1,400 to $2,800, and a continuous flow changeover $2,000 to $3,800.
Tell us the type, roughly the age, and whether it runs on a controlled load. If you are not sure about the last one, we can tell you at the property in a minute.
Kept if it can be kept, replaced if it cannot, with the tariff question raised first.
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