We've used SSI at our home for the last seven years. We have three zones in a 15 year old home. SSI has done a great job of replacing two of the old systems that were 13 and 14 years old. We have a maintenance contract with SSI. They do annual maintenance on the cooling systems in the spring and the heating systems in the fall. They respond quickly when we have a maintenance problem. One technican, Drew, has been assigned to our account since we started with SSI. He is superb. SSI service has been excellent in every respect, and we have no hesitation in recommending them. Marie and John Lane