GMC Heating and Cooling were the ones who installed our AC and heater units 15 years ago. Whenever we have any heating or cooling issues we call them every time. I have always been pleased with the service, and I am also pleased with the units they have installed. They are still working 15 years later, and we have only had to call GMC twice for maintenance issues. Their response time is generally pretty quick. The last time I called about an issue they were able to come out the next day. They are professional, courteous, and very friendly. I have no complaints with this company.