Raspberry Pi Net Zero: How Pi Towers Swapped Gas for Pis

Raspberry Pi has published a detailed look at how its own Cambridge headquarters, Pi Towers, is heading for net zero, and the most satisfying detail for any maker is that the company is running a big chunk of the job on its own boards. When the building's 17-year-old management system failed, Raspberry Pi replaced it with Pi-based hardware for a fraction of the quoted price, and paired it with Home Assistant to watch every circuit in the building.

• Cost: a like-for-like replacement for the failed Trend 963 building management system was quoted at about £150,000; the Raspberry Pi-based replacement cost £7,800.
• Monitoring: Raspberry Pi 4 and Raspberry Pi 5 units run Home Assistant with Emporia clamps on every breaker and the main supplies.
• Gas off: the building's gas supply was switched off on June 25, 2026, making July and August 2026 the first fully gas-free months.
• Target: net zero by 2027, with an 85.5kW solar array already live and a 219kW solar carport proposed.

How Did a Raspberry Pi Replace a £150,000 Building System?

A building management system (BMS) is the brain that runs heating, ventilation and air handling in a commercial building. The old proprietary Trend 963 at Pi Towers gave out in early 2026. Rather than pay roughly £150,000 for a like-for-like swap, the team chose BASview and BASpi from Contemporary Controls, an open BACnet control platform built on Raspberry Pi hardware. The bill came to £7,800.

The savings are only half the story. According to Raspberry Pi, the new system adds weather compensation, ventilation driven by CO2 readings, solar integration, and far more granular data on temperature, air quality and energy use than the old controller could provide. That is a strong case for the single board computer as serious building infrastructure, not just a hobby platform.

Home Assistant Meets Every Breaker in the Building

Alongside the BMS, Raspberry Pi 4 and Raspberry Pi 5 boards run the open-source Home Assistant platform, with Emporia current clamps fitted to every breaker and the main high-level supplies. The result is circuit-level visibility of where electricity actually goes, which is the foundation for every efficiency decision that follows. If you have been weighing up hardware for a similar setup at home, our Home Assistant hardware guide compares the Raspberry Pi 5 with dedicated hubs and mini PCs.

The Solar, Heat Pump and EV Numbers

Raspberry Pi shared a full set of figures for the rest of the programme:

• Solar: an 85.5kW rooftop array went live in June 2024 and has generated 192,000kWh in 26 months, with payback expected in about 2.7 years.
• Expansion: a proposed 219kW solar carport would lift the site to 304kW, covering an estimated 63% of predicted summer electricity demand.
• Heat and air: a hot-water heat pump, server-room heat recovery, motion-sensor extractor fans and per-floor damper controls save about 130,000kWh a year.
• Transport: 24 Easee EV chargers were installed in August 2024, a second bank of 24 is planned, and nearly 60 staff passes have been issued, up from 11 electric vehicles before the scheme.

What Is Left Before Net Zero in 2027?

The company describes its roadmap in three stages. Stage 1 is complete, Stage 2 is under way, and Stage 3 targets 2027. The biggest remaining job is heating: Raspberry Pi estimates the building needs 150 to 250kW of heat output and about 300,000kWh of heating a year, which now has to come from low-carbon sources since the gas boilers are off.

Why This Matters for Makers and Small Businesses

The lesson here scales down nicely. Open protocols like BACnet, open software like Home Assistant and inexpensive ARM boards can now do work that used to require expensive proprietary controllers. A small office, school or workshop could follow the same pattern: measure every circuit first, then automate what the data shows. For more projects like this, browse our mini computer and Raspberry Pi coverage.

Sources: Raspberry Pi — Net zero at Pi Towers: how we're doing it — October 8, 2026; Hackster.io — Raspberry Pi dogfoods its boards, connected to Home Assistant, as it plans a path to net zero — October 9, 2026.