If you don't hire these guys you're an idiot!
We have a home that is situated in a way that it gets sun on one side in the morning and the other side in the afternoon, so different parts of the house are hot or cold within a day. Other companies have tried altering ducts, changing the placement of thermostats, etc, but Guthrie & Sons Heating and Air was the first success for us.
They installed a zoning system for ventilation and maintained our filtration system to even out the temperature within the house.
This company is incredible. It is family owned, and I have gotten to work with all 3 brothers. They are sweet, professional and ethical and I would recommend them to anyone!