Most homes have a hot water storage cylinder, but how often do we really think about it? Hardly ever—until something goes wrong. If you suddenly find yourself with inconsistent water temperature, leaks, or reduced efficiency, it may be time to upgrade or replace your hot water cylinder.
There are two main types of hot water cylinders found in homes today: vented and unvented systems. These cylinders are typically constructed from stainless steel, copper, or vitreous (porcelain) enamel-lined carbon steel. Popular brands in New Zealand include Rheem and Rinnai.
Unvented hot water systems operate at mains pressure and do not require a cold water storage tank. This results in stronger water flow and a more consistent shower and bath experience. Additionally, because they do not rely on gravity, unvented hot water cylinders can be installed in any location within the home.
However, the main drawback of an unvented system is that if the mains water supply is interrupted, you will be left without hot water. Additionally, unvented systems require safety components such as pressure relief valves and expansion vessels to manage pressure buildup.
A vented hot water system relies on gravity, with a cold water header tank usually located in the roof space. The pressure of the hot water is determined by the height of the storage tank. Homes with vented cylinders often require electric pumps to improve water pressure, especially for upstairs showers and taps.
Vented systems tend to be simpler and more cost-effective but can suffer from inconsistent water pressure, particularly in multi-story homes.
Hot water cylinders are categorized as either indirect or direct systems:
• Indirect Systems: These use an external heating source, such as a solar, thermal, or gas boiler, to heat the water. A copper coil inside the cylinder transfers heat to the stored water.
• Direct Systems: These feature an internal immersion heater that directly heats the water within the tank.
Hot water cylinders are designed to last for decades, but they will eventually need to be replaced due to age, wear, or damage. Here are some key signs that it might be time for a new cylinder:
• Leaks: If valves or pipes are leaking, repairs may be possible. However, if the tank itself is leaking, replacement is necessary.
• Rust or Corrosion: Over time, the interior of a water cylinder may corrode. Most modern cylinders feature an anode rod to slow corrosion, but this component must be inspected annually and replaced if necessary. If rust forms on the tank itself, replacement is required.
• Inefficiency: Older cylinders, especially those without adequate insulation, can result in increased energy bills. Upgrading to a modern, more efficient unit can significantly reduce heating costs.
• Age of the Cylinder: Copper or stainless steel cylinders typically last 20 to 40 years, while glass-lined steel models have a lifespan of 12 to 20 years. If your cylinder was installed before 2002, it is worth considering an upgrade.
Replacing or upgrading a hot water cylinder is a job that must be carried out by a licensed plumber. At Mount Maunganui Plumbing & Gas, we specialize in hot water cylinder installation and servicing in Tauranga, Mount Maunganui, and Papamoa. Whether you need to replace an aging cylinder, upgrade to a mains pressure system, or improve your hot water efficiency, we have the expertise to get the job done right.
If you’re experiencing issues with your hot water system or would like professional advice on the best cylinder for your home, contact Mount Maunganui Plumbing & Gas today. We’re here to ensure you have reliable, efficient hot water all year round.
Mount Maunganui Plumbing and Gas is a local, family run business, servicing customers in the Mount, Papamoa, Tauranga , Te Puke and wider Bay of Plenty.
