An end-to-end PM case study: problem framing, sourced UK market and regulatory research, three personas, synthetic user interviews, an ICE-prioritized roadmap, and a working interactive viability-check prototype.
A working, coded viability-check calculator: postcode and segment (rooftop or plug-in) selection, self-reported consumption/tariff/occupancy inputs, and a green/amber/red result with the assumptions behind it shown openly. Built as a desktop web tool rather than a mobile app, so it's shown here on a laptop rather than in a phone frame.
The calculator is a full working tool. Open it full-screen for the real experience on your phone.
Quote opacity, sales pressure, and a shifting plug-in solar regulatory timeline, and where SunnySideUp sits against the UK's lead-gen comparison sites.
Three personas across both segments, synthetic interviews, and the cross-persona trust themes that shaped the roadmap.
ICE-prioritized Now/Next/Later, with the reasoning behind every score.
A working viability-check calculator covering rooftop and plug-in solar.
SunnySideUp doesn't sell, install, or take referral fees from installers. It's an independent viability check used at two moments: before any sales conversation, to set a baseline, or after receiving a quote, to get an unbiased second opinion. The closest real analog is Energy Saving Trust, a government/private-funded impartial-advice body, but even it defers the final personalized number back to the installer being evaluated. SunnySideUp gives that specific, personalized read directly.
No single figure captures the plug-in category's size yet since it's too new to measure, but two forward-looking signals and one comparable-market analog suggest real scale.
Government target for installed solar capacity by 2030, up from ~19GW in May 2025, roughly 2.5x growth in five years, with rooftop prioritized.1
English renters (~8.8M, ONS) plus owner-occupied leaseholders (~2.6M, MHCLG), the plug-in category's addressable population.2
Germany's comparable balcony-solar market, 2023 to mid-2025, growth accelerating after renters gained an explicit legal right to install in 2024.3
grounding-research.md §UK solar capacity trajectory.grounding-research.md §No-roof-access population size.grounding-research.md §Balkonkraftwerke growth in Germany.| Company | Model | Gap SunnySideUp targets |
|---|---|---|
| CompareMySolar, Solar Selections, Easy PV | Lead-generation / referral-fee | Paid per lead, incentivized to maximize quotes, not clarity |
| Uswitch solar comparison | Referral-fee comparison site | Same conflict of interest, general-comparison brand extension |
| Renewable Energy Hub, Solar Planet, Solar PV Quotes Compare | Lead-generation | Same referral-fee model across the board |
| Energy Saving Trust | Government/private-funded impartial advice | Closest structurally-independent analog, but its own calculator uses generic assumptions and defers the final number back to an installer |
No independently-funded platform identified in research gives a direct, personalized viability read without routing the user back to an installer. That gap is SunnySideUp's bet.
"I don't want a salesman doing my sums for me before I've even worked out if this makes sense."
An independent read on his specific financial case before any installer contacts him.
Pre-conversation viability check
"Two companies, two numbers four thousand pounds apart, and neither one explains why."
An independent check on whether a quote's price and system size are reasonable before signing.
Post-quote second-opinion check
"Everyone online says I can just plug it in. No two of them agree on whether that's actually still true."
A clear, unbiased read on both legality and value for a plug-and-play setup, calibrated to her own skills.
Plug-in viability + legal-status check, with an honest "still unresolved" flag
All three personas were interviewed with the same guide (AI-generated, in-character, grounded strictly in each persona's brief and real UK research, explicitly flagged as synthetic). Cross-persona themes directly shaped the roadmap:
All three trust conditions center on non-referral independence, and, for Aisha, a willingness to say "this part is genuinely unclear."
All three would accept an unfavorable result and change their behavior, specifically because of the non-referral positioning.
All three said they'd tell someone specific, a neighbour, a sister, a renters' Facebook group, rather than post publicly.
Her ceiling is structurally lower than the rooftop segment's for as long as the tenancy-consent question stays legally unresolved, independent of what SunnySideUp itself does well.
The plug-in calculator's Confidence score (6) is deliberately the lowest in Now. Aisha's segment is the newly-legal, most differentiated part of the pitch, but grounding-research.md itself flags plug-in cost and generation figures as its weakest-sourced section, and that caveat ships inside the tool's own output to real users, carried through to launch rather than dropped along the way.
Industry commentary on AI-assisted prototypes in 2025-2026 converges on one point: a polished demo and a shippable product are different things, and it's easy to mistake one for the other. A few of the gaps commonly named by product practitioners, applied honestly to SunnySideUp:
For anyone interested in documents on product development, platform and technical integration, growth, or product analytics, get in touch.