Solar Hot Water

An Investment for Your Future

Water heating can account for around 30% of your whare’s power bill, which means there is a lot to save with a Solartive Hot Water System. Solar energy is free energy – so make the most of it!

Make the most of solar water heating

The benefits you get from solar water heating are very dependent on how well your system is set up and managed.

A solar hot water system normally produces more hot water in summer because the sun shines for longer and is higher in the sky.  Sometimes there will be plenty of hot water and sometimes not enough. This is where a supplementary booster system will ensure you have enough hot water for your needs.

To make the most of your system you should use:

  • Water-efficient taps, showerheads, and appliances
  • Hot water efficiently, especially in winter
  • A timer or programmable control to make sure your booster system isn’t heating water you won’t need. For example, use the time to make sure your supplementary heating isn’t heating after early morning use if you are not home during the day.

An Energy-Efficent Solution

Solar water heating is a great option for your whānau as it is energy-efficient, has low running costs (typical water heating costs may reduce up to 75% in summer and 25–45% in winter) and has low greenhouse gas emissions. For best performance, the systems must be designed to suit your needs and installed correctly – and that’s where we come in.

We help you to consider how big the system will need at your house and go through options for the panel and cylinder locations, as well as the type of system and cylinder you want to use. 

How big should the system be?

The size of your solar water heating system will depend on your demand for hot water as well as the size of the panels. The Solar Association of New Zealand recommends that the cylinder size is approximately 75L volume of hot water for every 1m² of collector area. Typically, you should have 1m2 of solar panel collectors for every person in the house.

These numbers are a rough guide only. The actual cylinder size and collector area you need will depend on your individual household situation, the system you choose and the way it is configured and this is something the Solartive team will discuss with you.

A word of advice from over 20 years of experience, it’s not a good idea to skimp. Choose a system that will meet your home’s needs in the foreseeable future. If your home has four bedrooms, it’s a good idea to have a system big enough for four to five people even if only two people live there now.

Booster Systems

Booster heating systems help to keep the water hot when the sun isn’t shining. This could be gas, which can either be in a hot water cylinder or in a separate instant hot water unit downstream from the cylinder. Or heat pump exchange coils within the cylinder or a separate electric instant hot water unit downstream from the cylinder. Wetbacks can be particularly effective in areas with low sunlight hours in winter reducing the need for alternative booster heating. Some wetback systems can supply hot water when the power is off.


A controller manages the use of booster gas or electric heating and controls the pump in a pump system. It has a significant effect on the overall performance of your solar water heating system, so it’s important that it is set up correctly.
There are two types of supplementary heating controllers: time trigger controllers and minimum temperature controllers.

Solar Panels

Solar panels for hot water heating should ideally face north, although directions between northeast and northwest are usually satisfactory. They should be tilted towards the sun, with an optimum angle equivalent to your latitude, which we will help you to work out as it depends on your location. There are either flat plate panels or evacuated tube panels to choose from which again will depend on your location as they are relative to the sun coverage at your property, which we will carefully consider before installing.

Korero mai, Let's talk solar together