Product Design
Research
2021 ∙ NZHL
New Zealand

New Zealand Home Loans (NZHL) has been helping New Zealanders manage their home loans for over 28 years. Their offset mortgage structure links everyday accounts to the home loan, so customers pay interest only on the net balance. It’s a model that can shave years off a mortgage, but only if customers understand how to use it.

Their digital platform had barely changed since the late 2000s. It was powerful but advisor-dependent, visually dense, and closer to a spreadsheet than a product. Most customers couldn’t self-serve. NZHL needed a modern tool that gave customers clear visibility and control while keeping advisors central to the experience.

I joined mid-discovery as the sole product designer, leading UX strategy, usability research, and all design from concept to production-ready handoff.

Understanding the problem

The team had already run a competitor audit of the top five New Zealand banks and mortgage brokers before I joined. I came in at the research stage, working with two groups: first home buyers and refinancing switchers.

Three issues kept coming up. Customers had no real-time insight into how daily spending affected their mortgage. The offset structure felt opaque — even advisors struggled to explain it. And most customers avoided calling their advisor for small questions out of fear of wasting their time.

Design

Three hard constraints shape the work:

1. We had to follow a brand style set by another agency six months prior.

2. We needed seamless visual transitions between the website, app, and email, because trust is critical in financial services.

3. We had to maximise existing APIs rather than rebuild the legacy backend.

The design challenge was: how might we make complex mortgage mechanics understandable to non-experts, so customers can see the impact of their choices and advisors can guide them faster?

We explored several directions before converging. One early prototype explored a vertical timeline of future mortgage milestones — visually interesting, but too ambitious for the available data and confusing in testing. Another direction surfaced full financial breakdowns upfront, which recreated the same overwhelming feeling as the legacy tool. Each round of testing pushed us to strip back rather than add.

We gradually focused on what advisors told us clients actually ask about most: monthly expenses, regular repayments, and one-off lump sums. By the time we reached the final design, the interface had become significantly simpler than where we started — which is usually a sign the hard design work has been done.

The final solution centred on three elements:

1. Projection graph — shows the current payoff date, a comparison against a standard bank mortgage, and the compounding effect of NZHL's offset structure over time. Users consistently reacted with surprise at how much earlier they could be debt-free with relatively small changes.

2. "What if" panel — three simple levers covering expenses, repayments, and lump sums that instantly update the graph and key numbers like payoff date and interest saved. Customers and advisors can explore strategies together without leaving the screen.

3. Goals integration — personal goals like "Trip to Europe" or "New car" sit beside the graph, making trade-offs concrete rather than abstract. A more complex Goals and Budget feature was prototyped but removed after testing showed users didn't engage with it. It was preserved for in-person advisor sessions instead.

Advisors weren't just research subjects at the start — we kept them involved throughout, using design reviews and scenario walkthroughs to pressure-test decisions and make sure the tool worked for the way they actually run client sessions. We also ran structured usability tests comparing the final prototype against the legacy tool, with the development partner Deloitte Digital and the IT team present as observers. Their involvement built trust in the proposed solutions and helped resolve feasibility concerns early, which smoothed the handoff considerably.

Beyond the core brief, I explored two directions for future releases: an income and expense summary with spending by category, and a Debt Navigator AI tips feature to surface personalised suggestions. These weren’t part of the initial scope but felt like natural next steps — and sharing them early helped align the team on where the product could go.

Results

Not a number I measured myself — the project ended at handoff, and NZHL reported this after launch. The compounding-effect visualisation seems to have done its job: prospective buyers could finally see why the offset structure was worth acting on.

Advisors ran client sessions faster and with more confidence. Live scenario modelling and the "what if" panel let them answer questions in the session itself, rather than following up later with separate calculations.

Indigo Design Award

Gold Indigo Design Awards in Digital Tools & Utilities and Interactive Design. Bronze Indigo Award in UX, Interface & Navigation.

Reflection

Working across time zones with a New Zealand product team while being based in the UK meant I had limited involvement in the early stakeholder discovery. I had to get up to speed quickly, trust the groundwork done before I joined, and focus my energy where I could add the most value: shaping the research approach, running usability sessions, and driving design from concept to handoff.

The subject matter added another layer of complexity. Offset mortgages involve compound effects that most people don't think about intuitively, and designing something that felt simple without being misleading required many rounds of iteration. Every label, number, and visual had to earn its place.

London, UK