Recent Review: Superb. In my 66 years of life, I would only give an A + rating to a handful of vendors. Professional Radon Systems gets an A+. I did a ton of research including talking with the state of Illinois director who oversees the accreditation of radon mitigation contractors. I had 5 radon mitigation contractors provide estimates for the work needed. I had a very difficult situation. 1950 built house, slab, no basement or crawl. Red clay drain tiles are laid under the slab as HVAC ducts. These clay tiles could potentially be barriers to the radon mitigation system air flow. 4 out of the 5 contractors said 1) I had to seal these clay HVAC ducts with concrete and 2) Put in a whole new furnace and HVAC duct system through the attic before they would only guarantee a 3.9 pci/l. Total cost of the radon mitigation system and new heating system close to $20,000. Professional Radon Systems provided a 2.0 pci/l or lower guarantee for $3,900 with no changes to the HVAC system. You will probably not have this kind of situation or cost. Professional Radon Systems: 1) Was on time, 2) Finished the work in less time then was projected. 3) Friendly and highly professional. 4) Constructed a radon mitigation system that is concealed, meaning visitors don't see it, and quiet. 5) I am extremely neat. I had hand washed the attic. Some saw dust was left after their work. I could have cleaned it up in less than a minute, but I am a stickler for customer service. I asked for Professional Radon Systems to come back and clean it up. It was done within a couple of days. I had this service done in April 2017. Today, April 2019, my radon test shows 0.3 pci/l, significantly lower than the 2.0 pci/l guarantee. Everything is perfect.