R&D Heating and Cooling is a very timely, professional company, and I am very happy with their service. I would rate them five stars, for sure, and I would be more than happy to recommend them to others. I have a contract with them, which is very nice, and I really appreciate how easy they are to work with, and how reliable they are about unit maintenance for both of my units. They're friendly and efficient and I've never had any problems, at all. Thank you, R&D Heating and Cooling!