I did the same thing several years ago.  After getting several quotes, I selected Tony Beck Heating and Air located on Hwy 78 near Rosebud.  His proposal was the most logical for equipment and recommended duct changes, as well as his pricing.  His employees are very courteous and didn't mind answering any question and even provided insight as to why they were modifying the system. This has to be one of my better decisions that I've made.   Last but not least, Tony is a hometown business.

Tony Beck Heating
& Air Conditioning
 
845 Athens Highway, Loganville, GA
(770) 466-2924

Google Map location