I had One Hour Heating & Air Conditioning come out and install a heater for me, and that was the first time I ever used them. Since then, they just do the service calls, and routine preventative maintenance on the unit. Their employees are very careful to show up when they say they will, and also very friendly and polite. They are just really, really nice people, and they do a good job. They totally impressed me the way they came back out after the installation to make sure that my heater was working properly. Another time when they were here, they said my air flow was not putting out enough air, and they replaced it with a new one, and didn't even charge me! I really appreciated One Hour Heating & Air Conditioning for doing that for me!