How to choose the best solar hot water tank

Tanks come in a range of sizes designed to suit different houses and household requirements. Solar system tanks have a larger storage capacity than conventional hot water systems. They also have thicker insulation ensuring complete compliance with the stringent Australian Standards for Solar Hot Water Systems.

There are two types of material used in the manufacture of solar tanks; Vitreous Enamel & Stainless Steel. Keep reading for a few points and tips that will help you to select the right type of tank for your home.

When it comes to Vitreous Enamel, they are also known as glass lined tanks. They are solar rated and generally use a much thicker vitreous enamel lining than the standard main’s pressure hot water heater. This helps with the much higher solar temperatures experienced from the return line. 

Vitreous Enamel tanks are built to withstand very high pressures and water temperatures from hot to boiling. To protect the glass (enamel) lining an anode is placed down the centre of the tank. Called a ‘Sacrificial Anode’ it helps prevent corrosion and premature failure of the tank.
A magnesium anode is standard but aluminium versions are also used for areas with high Total Dissolvable Solids (TDS).

These tanks generally come with a 5 year warranty.

Stainless Steel is another popular choice. Australian made SS tanks come with a 10 – 15 year warranty. Although they have a slightly higher cost than a glass lined version, they do not require an anode and have significantly lower maintenance costs.

Although perfectly suited to most areas SS tanks are best used when water quality is good to high. In areas with lower water quality the impurities can eat away at the silver contained in the tank’s seam welds. This can lead to pinhole leaking and eventual failure. 

While SS tanks come with a longer standard warranty many manufacturers will not honour the warranty if the TDS of the water is above 600ppm (parts per million).