Smart electric hot water, Maroubra

This was a hot water replacement in Maroubra that started, as most of them do, with a damp patch. The existing system was an electric storage tank, roughly ten years old, and it had begun leaking underneath. A tank that has started to weep from the base is not a repair job, so the conversation moved straight to what to put in its place.

What went in was a Thermann Smart Electric storage tank, installed in the home's side passage. Filled, tested, no leaks, and the hot water was back on. The interesting part of this job is not the tank, though. It is the controller on the front of it, because that is where the running cost actually changes.

Why a ten year old electric tank starts leaking

An electric storage tank is a steel cylinder holding hot water under mains pressure, and it is protected from the inside by a sacrificial anode. The anode corrodes so the cylinder does not. Once it is spent, the tank lining starts going instead, and the first sign is usually damp underneath rather than anything dramatic.

Ten years is a fair innings for an electric tank in Sydney's Eastern Suburbs. It is not a fault so much as the end of the service life, and there is no repair for a cylinder that has corroded through. The reason it is worth knowing the difference is that a leak from the base means replacement, while water appearing higher up, at a valve or a fitting, very often does not.

What makes the Smart Electric different from a standard electric tank

Mechanically, very little. It is a conventional electric storage tank with a resistive element, so it heats water the same way the old one did and it plumbs in the same way. Sizing, pressure and pipework are all familiar. What it adds is a WiFi controller and a built in timer, which turn a dumb tank into one you can schedule.

The controller runs four modes. Manual works the way any old tank did. Schedule lets you set when the element is allowed to heat. Holiday shuts it down remotely when the house is empty, which is the one people underestimate. Eco uses the unit's own usage tracking to learn when the household actually draws hot water, then keeps heating to the minimum needed to cover it.

The tank carries a 10 year warranty. There is general guidance on the trade offs between the different hot water types on the Australian Government energy site if you are weighing electric storage against a heat pump.

Where the saving actually comes from

Not from the tank. A resistive element uses very close to the same energy to heat the same volume of water whichever tank it is bolted into. The saving comes from moving when that heating happens.

There are two versions of that. If the house is on a controlled load tariff, the heating gets scheduled overnight, when the rate is lower. If the house has solar, the better move is usually the opposite: heat through the middle of the day and use your own generation rather than exporting it and buying power back at night. The tank becomes somewhere to store the solar you are already making.

Which of those applies depends on the tariff and whether there are panels on the roof, and it is worth getting right at install rather than a year later. Once the schedule is set to suit the house, the unit is left alone. This is a different lever to the one a heat pump install pulls, where the saving comes from the efficiency of the appliance itself rather than the timing of when it runs.

Running out of hot water mid shower is usually not the tank

This is the part worth passing on, because it is the most common electric hot water call and the most commonly misdiagnosed. If your electric hot water runs out partway through a shower, that is usually a failing element or thermostat rather than the tank itself.

The logic is straightforward. A tank that is structurally fine but heating poorly gives you less hot water than it should, and it gives it to you inconsistently. Elements scale up and lose output, and thermostats drift or fail. Both are replaceable parts on an otherwise sound cylinder. It is worth having looked at at that stage, because the same tank left alone long enough becomes a leak, and a leak is a replacement. We have written more on the early checks before calling a plumber.

What to look for at your own hot water system

• Damp or staining underneath the cylinder, particularly on a slab or in a side passage where it dries between rain and is easy to miss. Water from the base points at the tank.
• Hot water running out earlier than it used to, or going lukewarm partway through a shower. That pattern points at the element or thermostat, not the cylinder.
• An electric tank at or past ten years with no record of the anode ever being checked. Age plus an unchecked anode is the combination that ends in a leak.
• Rusty water at the hot taps when the cold runs clear. That is the inside of the cylinder, and it is a replacement conversation.
• No timer or schedule on an electric tank. If the element is free to heat whenever the thermostat asks, you are paying whatever the rate happens to be at that moment.

How to reach Norton Plumbing

Norton Plumbing has worked in Maroubra and across the Eastern Suburbs since 2019, on hot water replacements and repairs, blocked drains, leak detection and general maintenance. I hold NSW plumbing licence 397768C and did this install myself. The team works out of 10/11a-15 Berwick St, Coogee. If your electric hot water is leaking or running short, see our hot water page, our Maroubra plumber page, or call 0477 858 951. Quotes are free across the Eastern Suburbs.