HestiaPi ONE (Silent)

Overview

The HestiaPi ONE (Silent) is a fully open-source smart thermostat built around a Raspberry Pi Zero W (or Zero 2 W) and a custom PCB. It gives homeowners complete control over their heating, ventilation, and air conditioning systems without relying on any cloud service or surrendering personal data to third parties. The 3.5-inch resistive touchscreen provides an intuitive local interface, while WiFi connectivity enables remote access through a smartphone or web browser running the openHAB home automation platform.

What sets the Silent variant apart is its use of Panasonic AQG22205 solid-state relays instead of traditional mechanical relays. These SSRs switch loads with zero audible click, making the thermostat suitable for bedrooms and quiet living spaces. The unit supports 3 to 5 relay configurations for single-stage through three-stage HVAC systems, covering standard US 5-wire 24V AC setups as well as European 240V AC installations.

Both the hardware and software are released under the GPL-3.0 license, with KiCad PCB design files, Gerber manufacturing files, and the complete openHAB-based firmware available on GitHub. The onboard Bosch BME280 sensor measures temperature, humidity, and barometric pressure over I2C, while a Hi-Link HLK-PM01 AC-DC converter allows the thermostat to draw power directly from the HVAC common wire. For users without a C-wire, a 5V Micro-USB external power supply can be used instead. The device ships fully assembled in a 3D-printed case (black or white) with a pre-flashed SD card, ready for wall mounting.