Mark and his crew arrived in the morning and did not leave until the job was done properly and to code. They had some tricky situations with the venting due to the location of the tankless waterheater and also had to upgrade the gas piping, but they figured it out and got it hooked up. Mark was very knowledgeable and answered all of my questions. I would definitely recommend Mark and his crew to anyone. My main concern is safety and code and they addressed them both.