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If this role excites you, get in touch ([email protected], LinkedIn) with your CV and a link to something you've shipped.

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🎯 About us

At Havenwise, we're making energy cheaper and easier for people. To do so, we’re building the hardware and software platform for home energy starting with the heating system, the single biggest energy load in most homes. We've already built and launched a software product that connects to heat pumps and cuts energy bills by ~40%.

We're now taking it further with our own hardware products: a smart hub and thermostat. The architecture is taking shape - a hub in the home that talks to the heat pump, communicates with the cloud, and connects to a wireless thermostat - but the key technical decisions are being made now. You'll help shape them, not just implement a spec.

With full control over the tech stack, you'll build the firmware foundation for the optimisation logic for electrified homes that measurably reduces energy bills. We’re backed by top VCs and angels who backed and founded the likes of Blueground, Huspy, Aikido, and many more. We have a strong network of installers to bring the new products to market in the next 12 months.

🔍 Your role

You'll be our first embedded engineer, owning the firmware and hardware integration delivery across two physical products: a mains-powered hub and a battery-powered wireless thermostat.

You'll work directly with the CTO and a small team of 3 engineers. This is a high-ownership role where your work ships to real homes.

Your responsibilities

• Own the full embedded stack: firmware architecture, hardware module selection, connectivity, and device lifecycle (provisioning, OTA, secure boot, watchdog).
• Build the communication layer between the controller and heat pump (Modbus RTU) and between the controller and cloud (MQTT).
• Design and implement the wireless link between hub and thermostat, optimising for battery life (12+ month target).
• Implement the thermostat screen UI in an embedded graphics framework. V1 is minimal - status, setpoint, boost - but it must look good, not just work.
• Build robust offline behaviour: the hub continues operating when internet drops.
• Build safety limits into the firmware so the device stays within safe operational boundaries at all times.
• Select and integrate off-the-shelf compute modules, radios, and transceivers.

What we're looking for

• You've shipped a consumer product with an MCU.
• Strong C. Comfortable with LVGL or equivalent embedded graphics.
• Experience with serial protocols (Modbus, UART, SPI) and MQTT.