Embedded Software Engineer (Firmware)

Nusku is leading the energy transition by developing an innovative connected heating system designed to make the move away from gas boilers more affordable, practical and straightforward. Our mission is to reduce the carbon emissions associated with heating the UK’s approximately 29 million households, while reshaping how people think about home heating.

We combine innovation with practical engineering to develop products that are efficient, reliable and designed to integrate into everyday homes. By improving comfort for our customers and lowering energy costs, we aim to accelerate the UK’s journey to net zero.

Who you are

You are a hands-on embedded engineer who enjoys working where software meets electronics and physical systems. You care about writing clear, maintainable C, but you are equally motivated by what the code makes happen: controlling real equipment, interpreting sensors, communicating reliably between devices and keeping a complex system operating safely.

You are curious, analytical and comfortable moving between architecture, implementation, bench debugging and whole-system testing. You explain your reasoning, collaborate well across disciplines and take ownership of turning prototypes into robust products for use in people's homes.

What the job involves

Initially, you will take ownership of the embedded software for a core controller within our heating product. The software coordinates multiple electrical and electromechanical subsystems, processes sensor data, communicates across a distributed embedded system and makes active safety‑related decisions about product operation. It must remain deterministic, diagnosable and resilient in real‑world operating and fault conditions.

Your responsibilities will include:

• Owning and developing production embedded C software for a core product controller, including its requirements, architecture, interfaces and coding standards.
• Designing deterministic control logic, state machines, interlocks, fault handling and safe‑state behaviour.
• Integrating sensors, actuators and hardware interfaces into a reliable embedded system.
• Implementing robust wired, wireless and industrial communications, including diagnostics and recovery from communication faults.
• Creating automated unit, integration and hardware‑in‑the‑loop tests, including fault‑injection tests for safety‑related behaviours.
• Debugging firmware and system issues on the bench, during product verification and in field trials, and translating findings into durable product improvements.
• Working closely with our software team, electronics development partners and colleagues across mechanical design, systems, test, manufacturing and compliance engineering to support board bring‑up, validation and the transition into manufacture.
• Over time, extending a common embedded C platform across connected in‑home products, supporting secure communications and remote product capabilities.

How we work

We are a committed team, driven to improve the heat pump experience for our customers and reduce the carbon emissions of home heating. We expect you to share these values and contribute actively to the mission.

This is a predominantly site‑based role in Bristol because close access to the electronics, test equipment and complete heating system is central to the work. There is scope for some home working when it fits the development and test schedule.

You will have meaningful ownership in a small, fast‑moving engineering team. We value practical experimentation, evidence‑led decisions, open technical discussion and the discipline required to turn ambitious ideas into safe, dependable products.

What we’re looking for

Must-haves:

• Strong experience developing and debugging production embedded C for microcontrollers and resource‑constrained systems, using bare‑metal firmware, an RTOS or both, with a sound understanding of embedded architecture, state machines, interrupts and timing.
• Experience integrating embedded software with sensors, actuators, communications interfaces and real hardware, using tools such as JTAG/SWD debuggers, oscilloscopes and logic analysers.
• Practical experience with industrial or device communications protocols, together with the ability to diagnose communication problems across a complete embedded system.
• A rigorous approach to automated testing, code review, version control, traceability and documentation, with thoughtful use of modern tools including AI‑assisted development.
• Sound judgement when developing software that controls physical equipment, including clear thinking about hazards, failure modes, interlocks and safe states.
• Strong collaboration and communication skills, including the ability to work effectively with electronics engineers and external development partners.

Nice-to-haves:

• Experience with wired and wireless networking for connected embedded products.
• Experience developing connected devices, including bootloaders, over‑the‑air updates, remote diagnostics and embedded cybersecurity.
• Experience with STM32 or ESP32 microcontroller architectures.
• Experience of hardware‑in‑the‑loop testing, fault injection, system simulation or test automation for embedded products.
• Experience of board bring‑up and close collaboration with outsourced electronics design or manufacturing partners.
• Experience developing high‑reliability or safety‑related embedded systems, ideally within HVAC, heat pumps, energy, industrial controls, connected products, domestic appliances or other products that control physical equipment or mains‑powered loads.

At Nusku, we believe in building an inclusive and supportive workplace where every team member can thrive.

We encourage collaboration, curiosity and continuous learning. As part of our team, you’ll enjoy:

• Being part of a mission‑driven company tackling one of the UK’s biggest sustainability challenges.
• The chance to work with a dynamic and supportive engineering team.
• Flexible working arrangements to balance work and life.
• Opportunities for professional development and career progression as we grow.
• 25 days of holiday each year, plus your birthday off as an extra treat.
• Comprehensive group insurance cover, including life insurance, income protection, and critical illness insurance (subject to standard eligibility criteria).
• Access to a virtual GP service and an employee assistance program for health and wellbeing support.
• A contributory company pension scheme (subject to scheme rules).
• A cycle‑to‑work scheme to support your health and sustainability goals.

Join us on our journey to transform home heating in the UK and play your part in building a greener, more sustainable future.

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