When my hubby got to be 80, I grounded him from getting on the roof and have hired DCM to maintain our master cool cooler and a/c/heater unit. The technicians came 12/12 and I was impressed with the professionalism and knowledge . I asked questions and got good answers . In a short time they had checked the heater and shut down the cooler. I am glad to have peace of mind about the units. Betty Baughman, metrocenter area