Quantity   Component name
2 × Raspberry Pi 3 B+
6 × SainSmart Solid-State Relay 1x Quad & 1x Dual
1 × SenseHAT Used for temp/humidity/barometer, and maybe the LEDs as an alert signal
1 × PiFace Digital 2 To interface the SSRs to the Pi attached to the heatpump. I may also use one of the digital inputs to track when the condensation drainage pump runs, and may also add leakage detection.