I had used Air Quality Control Agency for mitigation of Radon in my house. They did a very bad job with the installation. They didn't clamp the external venting pipe properly which kept banging on the wall on windy days and ultimately cracked my stucco. It took some months before we could realize where the noise was coming in from and on request to repair, they would charge $149 to fix something that was their fault. Their customer service is very bad and unresponsive. I am very disappointed with their service and wouldn't use them in future nor will recommend to any friends.