I would like to let you know how really appreciative we are of your excellent service in trouble shooting the HVAC air flow problem behind all the drywall in our home: from the start you were very quick to respond, you came and delivered a thorough inspection with your nifty gadget and your confidence in utilizing it, and you communicated and explained all findings clearly. You have helped us zero in on the area we need to concentrate on, which would have been impossible without your assistance. We have now found the problem, and heat starts to once again flow upstairs to my son’s room. Thanks again! We would certainly recommend Sigma for anyone requiring infrared inspections.