I called Chicago Heating & Cooling 1 Corp because my house did not have heat in the basement or in 3 out of 4 rooms of the second floor. Matt came to the house within the time range he said he would, called me before he arrived (excellent communications), and did a thorough check of the system including boiler and individual radiators. He did get the heat working again in the basement and diagnosed the problem, which could not be fixed then (from a practical standpoint) because of the excessively cold temperatures that day. He was very good and patient with showing me the issues and explaining clearly and thoroughly what was malfunctioning. I arranged for Matt to come back to do the repair a week later when it was warmer. Again, he worked industriously, discovered another part of the boiler system that was malfunctioning and fully explained the issue, showing me the malfunction, before obtaining the additional part from his distributor. Even with this unforeseen additional repair, the bill was well within his initial estimate. He does not charge an arm and a leg and he does explain charges/estimates before getting a commitment from his customers. I totally trust him and would recommend him to fix boilers and furnaces. He is very pleasant and works hard and is very knowledgeable of boilers and furnaces and hydronic heating systems.