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Water Heating 1 September 2016

Why Should I Switch to Mains Water Pressure?

If you’re timing your shower when someone isn’t using the kitchen tap to avoid an unwelcome blast of cold water, it’s likely your hot water supply is either low or unequal pressure (where the hot and cold taps are not of equal pressure).

Most New Zealand homes have an electric hot water cylinder and the ‘traditional’ New Zealand electric hot water system is what is known as ‘low pressure’. Low pressure (or unequal pressure) is when the hot water pressure is lower than the mains cold water pressure or between 10-50kPa.

Mains and Medium pressure are the other options. Medium pressure is where the hot water cylinder can be used at up to 120kPa. Mains pressure delivers up to 500kPa and provides water pressure that is about 6 times stronger than a low or unequal pressure alternative.

Most new homes are built with mains water pressure for hot and cold water, whereas a large number of homes over 20 years old use low pressure hot water.

How do you know if you’ve got a low pressure system?

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 your cylinder, then there are a few other ways to tell.

Firstly, if your cylinder is older than 20 years it’s most likely low pressure. If you have a very weak shower or significantly lower pressure at the hot taps compared to the cold, again, you probably have a low pressure cylinder. If you have a header tank in your roof cavity or a valve vent coming out the top of your roof, you have low pressure.

But if you have hot, powerful water blasting out of your shower, then you have mains pressure.

Why should you switch to mains pressure?

Today’s modern systems deliver much better performance. Here are five reasons for considering the change to a Mains Pressure Hot Water system:

1. Quick delivery of high pressure hot water. Once installed the flow of hot water will be similar to that of cold water; no longer the trickle that you may be currently experiencing. This means you can have multiple taps and showers running hot water simultaneously without a noticeable difference in flow.
2. Larger volumes of hot water. Older hot water cylinders tend to hold a smaller volume of hot water and are low pressure whereas modern hot water cylinders are high/mains pressure and most common sizes are 180 litres or larger.
3. Compatibility with modern mixers and taps. If you are looking to upgrade your home with modern or imported tapware, you may be left disappointed with your investment as low pressure systems won’t provide the best showering experience with unequal pressure.
4. Longer Warranty periods. Compared to Low pressure, Rinnai Mains pressure hot water cylinders are backed by a 20 year limited liability warranty (for Stainless Steel models) compared to just 5 years for a low pressure copper tank.

Can you upgrade your home from low to mains pressure?

Yes, and in most cases this is straightforward especially if it's a simple replacement of the existing hot water cylinder and valves for an equivalent mains pressure alternative. In some cases, you will also need to upgrade your tapware.

Now is the time to change.

If you’re considering a major renovation to your home, it’s a good time to consider moving to a mains pressure hot water system and enjoy the benefits of a strong, consistent flow of hot showers and avoid any nasty changes in temperature when someone else turns on the hot tap elsewhere in the house.

You can discuss your options with your plumber or explore our Hot Water Systems.