Yuki Hirayama

Monochrome

Joined as the 4th employee of a climate-tech startup developing solar, home-energy, and building-integrated hardware, bringing structure and execution to an ambiguous, fast-changing environment.

Led products end to end — from concept and prototyping through DFM/DFA, supplier sourcing, and production-ready specifications — with manufacturability and scale considered throughout. My role expanded into product management, including Japan market feasibility for Wall-1, ERP requirements definition and vendor evaluation for IPO readiness, new-product and partnership assessments, and selected marketing initiatives.

Three examples are shown below. Other work included a touch panel, a smart-breaker proof of concept, and UX/UI for an internal tool used for solar-panel layout and cost estimation.

Energy-1

Your home’s power. Reimagined.

Energy-1 device

Overview

  • Product design, concept development, prototyping, and QC requirements
  • Defined QC processes and disclosure requirements as part of the NDA framework
  • Production-ready 3D CAD and 2D/3D manufacturing drawings
  • Material and manufacturing-process selection with DFM/DFA considerations
  • User manual and packaging development
  • Factory sourcing, supplier selection, and price negotiation
  • Cost, schedule, and inventory management
  • Finalized production specifications and coordinated stakeholders through manufacturing readiness
Energy-1 advertisement layout
Energy-1 app screens

Results

Owned the development of Energy-1 end to end — from initial concept through production-ready manufacturing data.

Energy-1 in use

Design intention

Intentionally minimal. The physical design stays quiet, leaving room for the richness of the product’s functionality and user experience.

Decoration for its own sake would have conflicted with the company’s mission. Every additional material, finish, or manufacturing step carries an environmental cost — creating more waste for a product ultimately built around a more sustainable future.

Reducing unnecessary materials and processes also simplified production and significantly lowered manufacturing costs, helping the product meet environmental, operational, and business requirements.

Home-1 - Doorbell

One-off Pilot Installation

Wall-integrated doorbell: front and exploded view

Overview

One piece of hardware within the Home-1 system: a wall-integrated doorbell, built once as a pilot installation.

Scope

  • Product design, concept development, and prototyping
  • 3D CAD and manufacturing drawings
  • Material and process selection with DFM/DFA considerations
  • Supplier sourcing, fabrication coordination, and cost negotiation
  • Development through one-off fabrication and installation

Design intention

The design was intended to blend into the wall — quiet, unobtrusive, and visually restrained. The five concentric rings are a quiet use of the company’s identity.

Wall - 1

Walls. Powered by the Sun.

Wall-1 house in snow

Overview

Product management for Wall-1, a solar-powered wall system, on its Japan market feasibility. Worked across the company line: external testing facilities and partners for wind-pressure and water-tightness tests, overseas PV experts in recurring reviews, and press and marketing on how the product was presented. Internally, consolidated building regulations and construction constraints into a go / no-go framework and region-by-region rule tables for Sales and Architecture.

Results

Standardized how opportunities are qualified — faster proposals, less rework, and risks made visible through one set of decision criteria.

Selected Works