The difference, the pros and cons, and what to take into consideration before making the switch!
First up! What’s the difference?
Low-Pressure Cylinder:
Traditional New Zealand homes are usually equipt with a ‘low-pressure’ hot water system, which is an electric hot water cylinder.
Low-pressure cylinders are also known as ‘equal-pressure’ cylinders and are categorised by the water pressure being lower than the mains cold water pressure.
Water pressure is measured and expressed in a measurement called kilopascals (kPa) and metres head (m head), and therefore low/equal pressure cylinders provide water pressure between 10-15k PA.


Mains Pressure Cylinder:
New homes in New Zealand are mostly built with an equipped mains pressure hot water cylinder, providing high-pressure water as well as fast water heating. Mains pressure can deliver up to 500kPA, which is starkly different from the force delivered by a low or equal pressure cylinder.
Lots of people make the switch from low/equal pressure to mains pressure cylinders for several reasons, although there are advantages to having a low-pressure hot water system as well! In modern households where several people share a home, 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.)
The lower water pressure delivered can also be a pain for anyone who enjoys a powerful shower. People who like a full, hot shower – quickly, want a mains pressure system. The advantages of a low-pressure cylinder are the longevity of them as well as the simplicity, so for a home that only has to cater for one or two people, or as a holiday home, they are perfectly acceptable choices.
How Do I Find Out What Kind Of Hot Water Cylinder I Have In My Home?
The most direct way for you to find out if you have a low-pressure or mains pressure hot water system in your house is actually to look at the cylinder itself. Typically, somewhere on the label, it will be stated what kind of system it is, but if you can’t find any indication – no worries – there are other ways to find out!
- If you know how old your cylinder is, it is most likely to be a low-pressure cylinder if it is more than 20 years old!
- If the pressure coming out of your shower or hot taps are particularly weak, then the cylinder is probably a low-pressure hot water cylinder.
- If you experience in a high-pressure shower, then you have a mains pressure hot water cylinder.
So which hot water cylinder is better?
From a strictly performance-based review, mains pressure systems tick more boxes than low-pressure systems. If you live in a household with more than two people sharing the hot water or needing showers at the same time, low-pressure systems are going to probably be more a hindrance than a help. Again, if you are in a couple or a smaller flatting situation where you need to shower and get ready at the same time for work, depending on your low-pressure system, you may be waiting longer for hot water to make it to your shower or having to take turns.
Mains pressure cylinders also deliver a larger volume of hot water, with most modern sizes holding 180 litres or more – so is suitable for families, taking baths and high-level hot water use. There is also the quick delivery of hot water to be considered. If you need regular, fast, hot water to accommodate your lifestyle, then a mains pressure cylinder delivers hot water a lot faster than a low-pressure one.
As previously stated, the further away the shower is from the low-pressure cylinder, the longer the hot water will take to reach it. With a mains pressure cylinder, you can easily use multiple showers and taps at the same time without a big difference in the flow of hot water, which is ideal in families or for multiple people getting ready to leave the house in a hurry.
Modern taps, mixers and shower heads also may not work correctly with low-pressure systems, which can leave you disappointed in your purchase as you get a showering experience that doesn’t match what you bought the new head or mixer for.
Low-pressure systems struggle to keep up with the demands of a modern mixer, so make sure you know what kind of water system you have before investing in new fixtures.
Let’s recap the pros and cons super quick!
– Mains pressure delivers a lot of hot water fast and reliably to multiple fixtures at the same time. In contrast, low-pressure systems are slower to provide hot water and can struggle with that demand and dip in pressure and temperature across the house.
– Mains pressure is suitable for all new mixers, showerheads or fixtures whereas low-pressure systems may not be able to cope with the demand so the new fixture may not function as designed.
How a low-pressure hot water cylinder will save you money!
While mains pressure hot water cylinders are the new norm and preferred modern addition to any household, there is still something to be said for the simplicity and low maintenance of a low-pressure system. Depending on your household, you can decide which option is right for you!
Check out the Hot Water Shop’s comprehensive range of low-pressure, mains and outdoor cylinders and hot water systems here to find your perfect fit!
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