Electric Water Heater Installation and Replacement

There are legitimate cases. Apartments and units with no external wall, courtyard or service area cannot physically take a heat pump, since it needs airflow and produces noise and condensate. Some owners corporations will not approve an external unit. Internal cupboard installations and roof space tanks are the same story.

The other case is timing. When a tank fails on a Friday and there are three people in the house, a same day electric storage replacement is a reasonable decision. We will still tell you what the heat pump comparison looks like, but nobody should be pressured into a bigger decision while showering at a neighbour house.

Electric storage holds a tank of heated water and reheats it as it is used. Sizing matters because when the tank is empty you wait, and it is why undersized tanks generate complaints and correctly sized ones are invisible. As a guide, 125 to 160 litres suits one or two people, 250 litres suits three or four, and 315 litres or larger suits five or more.

Electric instantaneous heats water on demand with no tank, which suits a single outlet or a small flat, but the electrical load is very high. Whole of house electric instantaneous is generally impractical in domestic supplies because of the current it draws, and the switchboard and supply usually rule it out. We check the supply before recommending it at all.

Traditionally electric tanks were wired to a controlled load tariff that heats overnight at a lower rate. That still works, but for a household with solar it is often no longer the best arrangement, because energy exported during the day earns very little while the overnight electricity is bought at whatever the controlled rate happens to be.

Switching the tank to heat during the middle of the day lets it soak up your own generation instead. Whether that is worth doing depends on your tariff, your export rate and how much surplus your system actually produces. It is a wiring and metering change, so it needs an electrician, and it is worth modelling on your own bill before committing.

A tempering valve limits the temperature delivered to bathroom outlets, which is a scald protection requirement and is particularly relevant with children or elderly residents in the house. Tanks are stored at a higher temperature than that for hygiene reasons, so the valve is what makes the two compatible.

The pressure and temperature relief valve is the other one. It should be discharged briefly every six months and replaced when it weeps or fails to reseat. A relief valve that has been left to corrode shut is a genuine hazard, not a maintenance nicety. Electrically, the tank needs its own circuit and isolation, and any work we do is certified with a Certificate of Electrical Safety.

Elements and thermostats are routine replacements and worth doing on a tank under about eight years old. A leaking tank is not repairable, because the leak means the cylinder itself has corroded through, and at that point replacement is the only option.

The maintenance item that genuinely extends life is the sacrificial anode. It corrodes so the tank does not, and replacing it at around five years can add years to the cylinder. Most people have never heard of it and most tanks never get it changed, which is a reasonable part of why they fail when they do.