I somehow found out that a company I was considering is referred customers by Home Depot. Now, I figure that this company has to maintain a good level of service and try to not to get many unresolved complaints - thus, they need to be good at what they do or they jeopardize being the HVAC contractor that HD refers their customers to.
So, all things being equal, if they have been HD's HVAC contractor and HD is continuing the relationship, I would imagine they do good work and I should consider this greatly when choosing a contractor? BTW, they are also Factory authorized Carrier Dealers.
BTW, both Factory Authorized Carrier Dealers were not doing Manual J calcs - one said he knows based on experience and did a 550 per square foot method. Another one estimated the size of each room and was going to punch things into a computer - but didn't ask about insulation - doubt he looked at windows and orientation. So go figure.