Air & Heat Hospital come out twice a year to service our AC in the spring, and check the heating system in the fall. They make sure that everything is operational and that the units are working properly. They are thorough and always do a good job. In one instance we had to use them for a service call outside of the semi-annual checkups. We needed to have our 510 unit replaced, and that went very smoothly. Their team is professional and they work with their customers. Their prices are comparable, and probably cheaper than a lot of others. We will continue our service with them.