SunWiz’s Luminate platform provides unique monthly visibility into these KPIs — offering brand-level insights into what’s driving growth, and which levers actually deliver long-term results.
The two multipliers behind market share
Market share doesn’t appear by magic — it’s the result of two measurable factors:
1. Installer Adoption Rate: What percentage of active installers are using your brand?
2. Share of Installer Portfolio: What portion of each installer’s total deployments are your products?
These two levers work together. Winning over more installers increases your exposure, but unless your product range aligns with their needs, it won’t translate into meaningful volume. Similarly, even loyal installers can’t grow your share if they only use your product occasionally.
This chart illustrates how brands like Sigenergy have rapidly increased both their installer base and volume share over the past 12 months — leaping from 12% of installers in mid-2024 to 44% by May 2025.
ESY is a more recent market entrant to Australia and is very competitively priced. Though not yet used by many installers, ESY has considerably increased its share-of-portfolio of installers that do use it. However, ESY’s share-of-installer-portfolio has fluctuated considerably, which may reflect a price-driven nature of its adoption. Meanwhile while Tesla was still being used by a significant number of installers, it occupied a declining percentage of each installer’s portfolio.
Why product-market fit still reigns supreme
One of the most important — yet often overlooked — determinants of share-of-wallet is product-market fit.
Brands offering a flexible range of battery sizes, particularly stackable systems, are best positioned to serve both retrofit and new PV plus ESS customers. This adaptability has become more critical since the introduction of the federal battery rebate, which encourages upsizing (e.g., moving from a 13 kWh to a 20 kWh-plus system without doubling the outlay).
In contrast, monolithic batteries face a challenge: their fixed sizing can make them a poor match for subsidy-driven consumers who are upsizing for maximum value.
As shown in the capacity distribution chart below, Tesla dominates the 13kWh and 27kWh categories, but lacks presence in the many intermediate sizes where other brands thrive.
Installer loyalty: The hidden moat
Even as Tesla’s share-of-wallet shrinks, it maintains a strong loyal base: 90% of its recent installs are from installers who purchase Tesla every single month.
The loyalty chart below underscores this: Tesla continues to benefit from recurring trade, though its growth comes more from repeat customers than from new installer adoption.
Meanwhile, newer players like ESY have fluctuated in wallet share, indicating a more price-sensitive, potentially volatile customer base — one that might disappear when rebate conditions or pricing shifts.
Pricing cuts alone won’t win the race
In May 2025, SunWiz observed aggressive price cuts by many leading brands. But brands chasing short-term market share through pricing alone risk compromising profitability and brand perception. Winning market share is not just about being the cheapest — it’s about being the most installable, the most scalable, and the most repeatable choice.
Final thought: Know your levers
The lesson is clear: pricing, while visible and reactive, is only one of many market share levers. The most successful brands track:
● Share of active installers
● Share of installer portfolio
● Product-market fit
● Installer loyalty
And they act on what these metrics reveal.
Author: Warwick Johnston, Managing Director, SunWiz
SunWiz’s Luminate platform enables brands to monitor these KPIs monthly — offering unparalleled intelligence on battery brand performance across Australia (and globally). With the federal rebate reshaping the ESS landscape, this is no time to fly blind. Track loyalty, adoption, churn, wallet share, and more — all in one place. This content is available for PV panels, inverters, and ESS, in most global markets.
The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.
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