How Big Should Your Hot Water Cylinder Be for a Large Family in Wellington?

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If your household regularly runs out of hot water, the issue is usually not pressure — it’s capacity and recovery speed.

In many Wellington homes, the standard 180L cylinder is simply too small for modern family use. Multiple bathrooms, mains pressure systems, and back-to-back showers mean higher demand than older systems were designed for.

This guide explains what larger households should consider when upgrading.

Why 180L Is Often Not Enough

A 180-litre cylinder has long been the default in New Zealand homes. For smaller households, it can work well.

For larger families, it often leads to:

  • Hot water running out after 2–3 showers

  • Pressure drops during peak use

  • Waiting hours for the cylinder to recover

If you have:

  • 5+ people in the home

  • Teenagers taking long or multiple showers

  • Two or more bathrooms

  • A bath used regularly

You likely need a larger capacity system.

Larger Residential Cylinder Sizes (215L–340L)

For Wellington homes with higher demand, residential electric cylinders are available in larger capacities:

  • 215L

  • 250L

  • 275L
  • 28oL

  • 300L

  • 340L

The right size depends on:

  • Number of people in the home

  • Layout (distance between cylinder and bathrooms)

  • Mains pressure vs low pressure

  • Water-use habits

A rough rule of thumb is to allow 60 litres per person. However, a family of five with short showers will have very different needs compared to a family of five with two teens taking long showers morning and night.

There is no one-size-fits-all answer. Proper assessment matters.

Worried that a large cylinder won’t fit inside a cupboard in the house? There are models that can be installed outside, made to withstand the wild weather conditions here in Wellington.

Dual Element Cylinders: Faster Recovery

Most standard cylinders have one heating element.

There are also dual element cylinders, which contain two heating elements instead of one.

Benefits of dual element systems:

  • Faster water reheating

  • Better suited to high-demand households

  • Reduced likelihood of running out during peak times

In larger homes, recovery speed can matter as much as overall size. A dual element 300L cylinder can perform significantly better than a single-element unit under heavy use.

Large Homes: When Two Cylinders Make Sense

For some bigger Wellington homes — especially those with bathrooms at opposite ends of the house — installing two cylinders can be more efficient than one very large unit.

Advantages:

  • Hot water reaches taps faster

  • Less heat loss through long pipe runs

  • Lower electricity usage in some layouts

  • Better performance during peak demand

Water doesn’t have to travel the length of the house, which reduces both delay and wasted energy.

This setup isn’t necessary for every home, but in larger floor plans it can be a practical long-term solution.

Electric vs Gas in Wellington

While gas systems are available, we generally suggest electric hot water cylinders for Wellington homes.

Reasons include:

  • Ongoing uncertainty around gas supply

  • Rising gas pricing

  • Simpler servicing and maintenance

  • Strong performance from modern electric mains-pressure systems

For most large households, a properly sized electric system provides reliable, predictable hot water without fuel supply concerns.

Brands We Install: Rheem and Rinnai

We install and recommend:

Both manufacturers offer high-quality electric cylinders in a range of capacities suitable for larger homes, including dual element options.

They are well supported in New Zealand, with solid warranty backing and reliable performance.

Signs It’s Time to Upgrade Your Cylinder

  • Your household regularly runs out of hot water

  • The cylinder is 15+ years old

  • You’ve renovated or added another bathroom

  • You’ve switched to mains pressure

  • Your family size has increased

If your usage has changed, your cylinder should change with it.

Choosing the Right Size for Your Wellington Home

The correct solution depends on:

  • Household size

  • Bathroom count

  • Layout

  • Peak usage patterns

  • Available space

In some homes, a 215L upgrade is enough. In others, 300–340L or a dual cylinder system is more appropriate.

If you’re unsure, we can assess your current setup and recommend a properly sized electric system that suits your home long-term.

Need Advice on Upgrading Your Hot Water Cylinder?

If you’re in Wellington and your large household is running out of hot water, we can help determine:

  • Whether you need a larger cylinder

  • Whether a dual element system would improve recovery

  • Whether two cylinders would be more efficient

  • Which size and brand will suit your layout and your family’s usage

Contact us to discuss your home and get clear advice before replacing your system.

Earthquake-Ready Plumbing Checklist: How to Protect Your Home from Damage

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Although we don’t like to think too much about it, we live on a faultline so our city is seismically active and earthquakes are frequent. Even seemingly small rumbles can compromise your home’s plumbing. With this in mind, it’s worth performing a few checks that could reduce the chance of water damage and increase the chance of having a usable plumbing system after an earthquake.

We recommend doing the following checks at least annually as well as after any significant shake.

Earthquake Plumbing Checklist
  • Pipework – check all visible pipes (including under the house and in the ceiling if accessible) for leaks/cracks.
  • Hot water cylinder – are there any leaks?  Is it securely strapped?  Does it have an overflow tray?
  • Water toby – do you know where it is and how to turn it off? Is it working properly? (See our post about water tobies here for more helpful information)
Emergency Water Supply

We have installed an emergency rainwater tank outside our own house. We wrote a post about it, which you can read here to learn more about how they work.   It’s reassuring to know we have 200 litres of water stored if we need it.

When using water from a tank to drink or brush your teeth, the usual precautions are recommended – either boil the water or add a few drops of household bleach. Rainwater tanks can be strapped to protect your extra water supply in earthquakes.

You won’t regret taking a little time to go through the checklist above. Attending to each point will reduce the plumbing issues you experience after an earthquake. There’s peace of mind knowing that you’ve done what you can to be prepared. If you spot something that you would like to have checked/fixed or you would like a rainwater tank installed at your place, please get in touch.  Craig would be very happy to help.

Fix Weak Water Pressure & Enjoy Your Morning Shower!

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The most common complaint people who have a low pressure hot water system make is that they have weak water pressure at the tap. They want to luxuriate under a decent spray for their morning shower, not shiver under a dribble. Another problem some experience is difficulty controlling water temperature with mixers.

Read more

Save Money on your Power Bill!

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Winter is officially here!  It has certainly made its presence felt in Wellington over the past week. As we dig out our warm coats, turn on heaters and stay an extra few minutes under the shower to warm up, we also brace ourselves for a hike in our power bills.

On average, heating of hot water accounts for 1/3 of your power bill! There are a number of ways to make your hot water system run more efficiently and reduce costs. Craig can check over your system and make power-saving suggestions that fit your budget.

Some of the affordable measures Craig can take are to:
  • insulate hot water pipes with lagging to reduce heat loss.
  • install flow restrictors in showerheads and taps to reduce the amount of water used.
  • adjust the settings of the thermostat and tempering valve on your hot water cylinder so it’s not heating more than it needs to.

In recent years, plumbers have switched to a new system for running water pipes from the hot water cylinder to taps and showerheads. Using 12mm pipe to run water to each tap directly from the hot water cylinder saves 2/3 of the hot water consumed by the old way of doing things (which was to use one 20mm pipe to serve all taps and showerheads in an area).  Using the new method, less water has to be drained from the pipes before hot water arrives at the tap. This might be worth considering if your pipes are accessible (such as under the house or in the ceiling space), need replacing anyway due to a burst or other problem or you are renovating.

You might want to consider installing a hot water heat pump as we have done recently in our family home. Manufacturers guarantee they save 2/3 of your water heating costs, making heat pumps a good option for those who intend on staying in their current house for many years to come.  Your existing hot water cylinder may able to be used with a new heat pump.

Craig would be very happy to pay you a visit and make opening your power bill an easier task!

Keep warm this Winter,
Craig & Julie