There's a lot of fear over things like black mold in the states. It's extremely rare but it can be life threatening, and it's one of those things that people see and get nervous about when they see that for instance their HVAC vent has mold spots, that they are breathing toxic air. 9 times out of 10, it's totally fine. This method mentioned above gives homeowners the peace of mind that they aren't poisoning their families accidentally for an extremely affordable price. The alternative of calling mold remediation experts in is going to be extremely pricey, and those people cannot be trusted to be upfront on whether your mold problem is 1. actually a problem and 2. actually dangerous - because they make money on selling expensive remediation solutions.