OneEnergy

Hot water is one of the largest energy expenses for New Zealand households, typically accounting for 30–50% of electricity use. For the 700,000 households with constrained incomes, these bills can be a major burden. Many of these homes still rely on traditional electric hot water cylinders, which are both costly and carbon intensive when powered 100% by conventional mains electricity.

OneEnergy.nz has a clear mission: to bring affordable energy to all Kiwis, rapidly. With support from Ara Ake, the company trialled its innovative solar electric hot water system in eight homes cross Auckland and Christchurch, including two community housing units. The aim was to test performance, savings, and user experience in real-world conditions, with a particular focus on low-income households where the impact could be most profound.

Impact unlocked

The system uses a minimum of six solar panels per home to heat water directly, avoiding the complexity of exporting power back to the grid. Mains electricity provides backup when sunshine is low, allowing households to use most of their solar energy for water heating. Designed to integrate seamlessly with existing hot water cylinders, the system requires minimal installation effort and is expected to pay for itself within five years. During the trial, homes of varying sizes and usage patterns took part, and early feedback guided refinements to the heating algorithm to ensure hot water was always available in the evenings.

Households reported lower power bills, reliable hot water and high satisfaction, rating the system 5 out of 5 for recommending it to others. Even in winter, solar supplemented with mains boosting met households' hot water needs, and households with higher use identified the potential benefits of slightly larger setups. Initially aimed at addressing energy hardship, the pilot also attracted households seeking affordable solar options, greater energy independence, solutions for limited roof space, and alternatives to heat pump systems.

Ara Ake contribution

Ara Ake supported OneEnergy.nz by facilitating the pilot and enabling collaboration with participating households. This partnership is helping demonstrate a practical, rapidly scalable, affordable pathway for households to access solar energy - reducing costs, lowering emissions, and addressing energy hardship across Aotearoa.

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“We’re delighted to have Ara Ake’s support. The value in removing most of a household’s water heating load from their energy bill is not just a big win for the household, but an even bigger win for grid flexibility as we scale this into thousands of homes. We’re seeing all walks of life adopt our solution, particularly those that aren’t ready to make the more substantial investment into grid-tied battery systems, and are happy to start their solar journey with a simpler yet effective solution.” Steve Hooker, CEO, OneEnergy.nz

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www.oneenergy.nz

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