after being told that they recommended my getting a specialty fan to preview CO2 poisoning with my air seal, they replaced it 2x before they realized it was supposed to run 24/7, which was strange to me. I called the fan company, who told me it was just a simple bathroom fan. What a scam. I already had a bathroom fan, which they knew. For $500 they had put in another bathroom fan, which I didn't even need.