> There are several items missing here

Already accounted for. But if an installer cares to detail actual costs for a ducts and loop already in place 4 ton geo install, please do so.

You are not likely to attract those details.

Why?

Because every job has so many unique characteristics that it isn't feasible to nail down every last detail during the proposal phase. To wit: I'm on a 2 system, 5 zone beachfront project right now where the plumber, electrician, and interior framer got in before me and forced a total rework of my duct plan. Much of what I bought for the job will get exchanged for different components. Fortunately I knew going into this job that the constraints imposed by a very thin steel joist system were going to cause me headaches, so I factored that into my thinking about the job. That said there is no way I'd get into those details with the client. Rather, I've applied a mental "PITA factor" to the job, and if the money isn't there to deal with that then it is an excellent opportunity for one of my competitors...let him die trying to take that hill...

+1 Curt,

I have adopted the attitude that the best gift that I can give my competition is a job they can not succeed at with out substantial monetary pain on thier part. Everyone applies a pita factor to jobs that warrant it.

What has always bothered me about the "cost" question, is that it begins with the flawed on-looker opinion that there is no more cost to a job than material and labor.......the road to bankruptcy is paved with the bones of contractors who thought the same.
Frankly the biggest failing of most contractors is undervaluing their time/over estimating what they make once all the overhead is paid.
The internet age and ability of consumers to discover the cost of equipment, has tempted a few customers to try to nit pik my estimates. Those who ask generally are well paid for jobs with less individual responsibility and often have less time at their craft. They also do not expect to be bothered by phone calls from their employers on evenings or weekends. Yet they defend their pay rates and challange mine (usually on evenings or weekends when we run the bulk of our free estimates).
joe

I'm in the process of quantifying for myself what Joe describes above. The cost in time, mileage, and sheer aggravation involved in determining. listing and acquiring all the ducts, boots, cables, registers etc needed for a given job is astounding. Then there is the oversight responsibility in ensuring that all is installed in a rational, code-compliant manner despite endless constraints and roadblocks imposed by plumbing, wiring, framing etc. placed in the way of ductwork.

The materials are quite cheap relative to the cost of getting them properly deployed, and I expect to profit from making it happen properly. If I can't derive enough profit from the process to keep me in some steak and beer then it needs to be someone else's project.