Low-Pressure vs Mains Pressure Hot Water Systems

Electric hot water cylinders are the most common form of water heating in New Zealand. Until the 1970s, low pressure electric water heaters were the main option available to they are commonly found in older NZ homes and are also often a reality of rural living.

What is a Low-Pressure Cylinder?

Ever get blasted with cold water while taking a shower and someone opens the hot water tap in the kitchen? You may have a low-pressure hot water cylinder. These systems commonly struggle when hot water taps are being used in different areas of the house. This is because low-pressure cylinders (also known as equal-pressure cylinders) are categorised by the water pressure being lower than the mains cold water pressure.

Hot Water Cylinder

What is a Mains Pressure Cylinder?

New homes in New Zealand are mostly built with an equipped mains pressure hot water cylinder, providing high-pressure water as all as fast water heating. This type of cylinder is closed-vented, so you won’t find a vent pipe anywhere.

Lots of people make the switch from low/equal pressure to mains pressure cylinders for several reasons. Low-pressure systems can be inconvenient due to how long it can take for water to heat up (and it takes longer the further away the tap or shower is from the cylinder). Low-pressure can also be a pain for anyone who enjoys a powerful shower. People who like a full, hot shower, prefer a mains pressure system. With a mains pressure system, hot water is delivered to the entire house at the same pressure, so it’s less affected by multiple demands on water usage, such as simultaneous showers, running taps or washing machines.

Man in Shower Frustrated

Check your Hot Water System before buying new fixtures

If you’re looking to upgrade your bathroom or kitchen with modern or imported tapware, you may be left disappointed and limited in your choices if you have a low-pressure system.

Most modern taps, mixers and shower heads may not always work correctly with low-pressure systems. It is advisable that you check your hot water system before investing in new fixtures.

Shower Pressure

How do you know which system you have?

  • The easiest way to tell is to look at the hot water cylinder. If it’s not clearly marked ‘mains pressure’ on the side of the cylinder, then there are a few other ways to tell.
  • If your cylinder is older than 20 years it’s most likely a low-pressure cylinder.
  • If you have a weak shower or significantly lower pressure at the hot taps compared to cold, you probably have a low-pressure cylinder.
  • If you have a head tank in your roof cavity or a valve vent coming out the top of your roof, you have a low-pressure cylinder.
  • A low-pressure cylinder also has a large pressure reducing valve (that looks like a flying saucer) on the cold water inlet.
  • But, if you have hot, powerful water blasting out your shower, then you have a mains pressure system.

Reasons to upgrade to a Mains Pressure System

  • Quick delivery of high pressure hot water at the same time.
  • Larger volumes of hot water (most common sizes are 180 litres or larger)
  • Compatibility with modern mixers and taps
  • Longer warranty periods in some cases

Contact us for your hot water system upgrade

If you’re considering a renovation, it’s a good time to consider upgrading to a mains pressure hot water system. Contact JT Plumbing, Drainage & Gas to discuss your options.a