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Solar hot water

Installing a solar hot water system is a sustainable and cost-effective option for water heating.

How it works

Solar hot water systems use the sun to directly heat water and store it in a water cylinder.

They can either be installed as flat panels or evacuated tube panels, and can have the cylinder placed on the roof or in an internal hot water cupboard.

You'll also need a booster system (usually electric) to make sure you have enough hot water when solar is reduced, for example in winter and at night.

Sizing and costs

Solar hot water systems can cost between $4,000 and $9,000 depending on the size of the system, hot water cylinder and installation.

It's important to have a large enough hot water cylinder to maximise efficiency.

In general:

  • a relatively water-efficient household will have a system size of 75-100 litres per person
  • a typical solar hot water panel is 2 square metres and will supply 150 litres
  • So, a typical 3-4 person family will need a system sized at 300 litres which has 2 panels.

Find out more: Smart Homes - Solar water heating options

Before you buy and install

You need to think about:

  • what size system you need
  • what type of collector system
  • what hot water cylinder you want to use
  • the location of the panels and cylinder.

If you're installing a system that has the cylinder on the roof, you should consider weight and roof structure. These types of systems are generally more suited to climates with milder winters.

All solar water heating systems must be installed by a qualified and experienced plumber.

Check if you need building or resource consents