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What size hot water cylinder do I need?

Which hot water cylinder size is best for me?

There are three main sizes of hot water cylinders: 180ltr, 250ltr, 300ltr. Picking the right hot water cylinder depends on how many people live in the house. Here’s an easy hot water cylinder size guide:

  • 180ltr: 2-3 people household
  • 250ltr: 2-5 people household
  • 300ltr: 3-5 people household

Top tip: the average person will use 50ltr of hot water a day.

But there are more factors to consider when choosing the right hot water cylinder size. These include: 

What size hot water cylinder?

1. How much space do you have?

How much space you have will determine the size of hot water cylinder you can install. Some types of hot water cylinders can be installed outside, saving you valuable indoor space.

If you have the space for it, it’s usually wise to make use of this and opt for the biggest cylinder you can get. That’s because your energy efficiency increases when you’re able to store more water. You won’t be using more energy, and temperature loss is minimal, but you’ll be heating more water that’s ready to use.

Having a bigger Solar Ready hot water cylinder also helps future proof your system. If you want to switch to a cheaper, alternative form of energy later on, a bigger cylinder will help you out. When using alternative energy sources, you want to heat as much water as possible during certain hours, e.g. when the sun is shining - so more storage is your friend. If you can afford the price difference now, we say go for it.

Top tip: Hot water cylinder prices vary between sizes. Typically, a 300ltr cylinder will cost you $300 more than a 180ltr one.


2. How much water do you use?

Are you someone who can’t live without a nice, long shower before bedtime? While most people use 50ltr of water a day, this increases if you’re frequently in hot water – and we mean this literally.

Above-average warm water usage includes: 

  • Taking long showers ‒ shower heads dispense up to 20ltr of water per minute.
  • Using the dishwasher often ‒ the average dishwasher uses 10 to 12 litres of water per wash.
  • Often washing clothes in warm water ‒ this can use up to 10 times as much energy as a cold wash.

Top tip: If you find your household using above-average hot water daily, then it’s best to opt for a 250ltr or 300ltr hot water cylinder.

How much Hot Water?

3. What time are you home?

No one likes getting stuck in a cold shower. That’s why when choosing your hot water cylinder size, you should always consider the time of day you’re typically home. This will be when the showering, dishwashing and laundry happens ‒ all activities that require hot water.

With these numbers in mind, you might find it helpful to use the government’s EECA Energywise calculator that allows you to calculate which hot water cylinder will work best for your household.

Top tip: If everyone in your household uses the hot water at peak times, a larger hot water cylinder is best. Simply put, the bigger the cylinder, the less likely you’ll be stuck in a cold shower!


Call us to talk about a budget that suits you

Looking for help picking the right hot water cylinder size? Or do you want to compare hot water cylinder prices? AllGo Plumbing’s helpful and experienced 24hr plumbing team is always happy to answer all your hot water cylinder queries.


Give us a call on 0800 255 758 or fill in our contact form and get a free quote and assessment now.


Tags: Hot Water Cylinder Size Hot Water Cylinder

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Master Plumber Auckland
Rheem and HJ Cooper