I have an energy efficient, air tight home (ICF construction). The HVAC vendor determined that an energy recovery ventilator (ERV) was needed. The did the entire installation and included an Aprilaire Model 8100 ERV. However, they did not include a controller - the ERV runs constantly. Yes, it pre-conditions the fresh air coming in, but it is not 100% efficient so I have to condition the fresh air that is replacing the exhausted stale air. The ERV should be running no more than 50%, not the 100% it is currently running.
The simplest solution is a timer, set to run the ERV 30 minutes of each hour. ERV has an input for a controller (currently not connected). Per the manual, the signal is 24 VAC, dry contact, normally open. I have a 24V transformer. My idea is to switch the 24 VAC using a relay. I could use a simple timer from WalMart, but I would rather control from HA, where I can adjust the algorithm as I wish.
My current thought is to use a wifi smart plug to connect to HA. The plug would be controlled by the HA algorithm, the output driving the 120 VAC coil of the relay that switches the 24 VAC to the ERV.
I am looking for comments and advice from the community. My questions:
Q1. What smart plug to buy? Amazon recommends Eightree, but based on reviews I have questions about its reliability. Kasa was recommended by a reviewer, but there are questions about whether an online account is required. I have a firewall on my network (pfSense) to keep out unwanted guests, and I want all the control of my IOT to be local.
Q2. Is wifi the best choice for a smart plug? I chose it because no additional hardware is needed. I looked into a relay with a 5 VDC coil that could just be wired to the Raspberry Pi running HA, but these seem to be considerably more expensive on Amazon. I checked Grainger (expensive) and Digikey but got lost in the Digikey catalog. The Amazon sourced relay I selected has reliability issues but it’s cheap and I am not switching a lot of power so I took the chance.
I am new to home automation and Home Assistant, so appreciate any insights.