I had a furnace install they show me how the old furnace (7 years old and 8 months) was installed incorrectly. It had not been converted to propane gas there was no low pressure switch on it which cause the furnace to soot up and damage it.
The technicians were very professional helpful to answer any question that I had. They did a excellent job and clean up after all their work was done. I would highly recommend them to anyone who wants to have work done right the first time.