They came when promised and called a half hour before arriving. Andriy took the dryer apart, cleaned it and then determined that although we had attempted to clean the vent system by ourselves we had not reached the upper portion. He went up into the attic and took apart the vent and cleaned it completely. He found the last section with the flap had been installed incorrectly by the builder not allowing air to flow out of the house. Thorough, on-time, and charged what they quoted!